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Contact InfoJournal Highlights
Articles from across all AGU journals that have been selected by Editors because of their significant import to the geosciences.
Small dams need better management (31 January 2012)
Many small dams around the world are poorly maintained and represent a safety hazard, according to Pisaniello et al. (2012). Better oversight of small dams is needed, the authors argue. The researchers reviewed literature, conducted case studies in four... (Water Resources Research) [more]
Estimating sediment transport in rivers using seismic detections (28 January 2012)
Rocks and sand carried in a river's flows, which bump, grind, and scrape against the riverbed, are an important force in driving topographic change by controlling riverbed erosion and incision rates over long time scales. Sediment transport observations collec... (Geophysical Research Letters) [more]
Improving forecasts of volcanic ash concentrations (27 January 2012)
Volcanic ash can severely damage airplanes, and eruptions such as the 2010 Eyjafjallajokull eruption may result in major disruption to air travel. Improved forecasting of ash cloud locations and concentrations could benefit the aviation industry and reduce del... (Journal of Geophysical Research - Atmospheres) [more]
Vertical swimming helps bioluminescent phytoplankton avoid being carried by currents (25 January 2012)
Observations of an upwelling event in Monterey Bay, California, show that nonbioluminescent phytoplankton from the northern part of the bay are carried with the southward flowing currents along the entrance to the bay, but many bioluminescent dinoflagellates a... (Journal of Geophysical Research - Oceans) [more]
Tracking meltwater retention in Greenland (25 January 2012)
In Greenland, surface melt has increased significantly in area and intensity in recent years. Melting has increased in the accumulation area, normally a region of snow accumulation. This increase in meltwater can affect the ice sheet's mass balance and ice flo... (Journal of Geophysical Research - Earth Surface) [more]
Effects of sea spray geoengineering (25 January 2012)
Anthropogenic climate warming is leading to consideration of options for geoengineering to offset rising carbon dioxide levels. One potential technique involves injecting artificial sea spray into the atmosphere. The sea salt particles would affect Earth's rad... (Journal of Geophysical Research - Atmospheres) [more]
Magnetospheric source of auroras tracked down by satellite fleet (25 January 2012)
Prebreakup arcs (PBAs), thin, faint tendrils of glowing gas stretching thousands of kilometers in either direction, are very different from the multicolored lights typically associated with auroras. PBAs develop a few minutes before the onset of the full displ... (Journal of Geophysical Research - Space Physics) [more]
Passive margin earthquakes: Reviewing knowledge and challenges (24 January 2012)
Earthquakes that occur on "passive" continental margins, such as the August 2011 magnitude 5.8 Mineral, Virginia, earthquake, surprise people because they expect earthquakes to occur only on plate boundaries. But, in fact, large and damaging intraplate earthqu... (Geophysical Research Letters) [more]
New details on magma chamber beneath Soufrière Hills volcano (20 January 2012)
Assessing volcano hazard and forecasting eruptions require knowledge of the geometry and properties of a volcano's magma chamber. However, there are few high-resolution seismic imagery studies of magma chambers. Paulatto et al. (2012) used seismic tomog... (Geochemistry, Geophysics, Geosystems) [more]
Capsizing icebergs release earthquake-sized energies (20 January 2012)
A large iceberg can carry a large amount of gravitational potential energy. While all icebergs float with the bulk of their mass submerged beneath the water's surface, some drift around with precarious orientations—they are temporarily stable, but an out... (Journal of Geophysical Research - Earth Surface) [more]
In Japan, seismic waves slower after rain, large earthquakes (20 January 2012)
An earthquake is first detected by the abrupt side-to-side jolt of a passing primary wave. Lagging only slightly behind are shear waves, which radiate out from the earthquake's epicenter and are seen at the surface as a rolling wave of vertical motion. Also kn... (Journal of Geophysical Research - Solid Earth) [more]
Martian carbon dioxide clouds tied to atmospheric gravity waves (20 January 2012)
On 4 March 1997 the Mars Pathfinder lander fell through the thin Martian atmosphere. During its descent, instrumentation aboard the lander recorded the changing atmospheric temperature, pressure, and density. Within this atmospheric profile, researchers identi... (Geophysical Research Letters) [more]
Revealing the structure of a terrane in southern Alaska (19 January 2012)
In southern Alaska, multiple terranes—slabs that have broken off from larger tectonic plates and shuffled around—create a complex patchwork that makes it challenging for scientists to untangle the tectonic history and structure of the region. One o... (Journal of Geophysical Research - Solid Earth) [more]
Photochemical reactions a sink for dissolved organic carbon (19 January 2012)
Dissolved organic matter is transported from inland sources through rivers to seas, where it provides a major source of carbon and nitrogen in aquatic ecosystems. Solar radiation can break down dissolved organic matter into a form that is more readily used by ... (Journal of Geophysical Research - Biogeosciences) [more]
Earthquake-triggered avalanche altered glacier flow (18 January 2012)
Landslides are common in areas with mountain glaciers and could affect the movement of glaciers. Shugar et al. (2012) used satellite radar imagery and numerical modeling to investigate the effects of earthquake-triggered avalanches on the Black Rapids G... (Journal of Geophysical Research - Earth Surface) [more]
Abrupt decline in East African long rains (18 January 2012)
In 2010–2011 the East African region suffered a severe drought that affected millions of people. The drought was a consequence of the failure of both the seasonal "short rains," which typically run from October to December, and the following "long rains,... (Geophysical Research Letters) [more]
New record of climate history in central Asia (13 January 2012)
The climate in Central Asia, currently a semiarid region, has varied over the past 500,000 years. An accurate record of the past climate can help scientists understand current climate and better predict how the climate may change in the future. Previous studie... (Geophysical Research Letters) [more]
No trend in Antarctic snowmelt volume (13 January 2012)
A new study that measured Antarctic snowmelt volume found no significant trend over the past 31 years. Kuipers Munneke et al. (2012) used satellite microwave sensors, which can detect meltwater, combined with a regional climate model that includes snow ... (Geophysical Research Letters) [more]
Information flow in a landscape has a direction (12 January 2012)
Sediment flux and other properties in a landscape are often influenced by landscape properties at points away from the point of interest. How does information flow from these distant points to the point of interest? Voller et al. (2012) developed a math... (Geophysical Research Letters) [more]
Continuous observations of North Atlantic heat transport (11 January 2012)
The Atlantic meridional overturning circulation (AMOC), which transports warm water northward and cold water back southward, is important in transferring heat to the North Atlantic Ocean. Some models predict that AMOC will slow down as Earth's temperatures ris... (Journal of Geophysical Research - Oceans) [more]
Io's volcanism influences Jupiter's magnetosphere (11 January 2012)
Volcanic emissions from Jupiter's moon Io supply plasma to the planet's magnetosphere and lead to its main auroral emissions. New observations show that the main auroral oval expanded and outer emissions brightened in spring 2007. Some studies have suggested t... (Geophysical Research Letters) [more]
Arctic sea ice surface ponds due to saltwater impurities (5 January 2012)
During the summer melt season the white surface of Arctic sea ice turns to a mixture of grays and blues as meltwater ponds come to dot the landscape. Rising temperatures in late spring melt ice and snow, and the meltwater pools in depressions left by drifting ... (Journal of Geophysical Research - Oceans) [more]
Observing noctilucent clouds from space and ground (5 January 2012)
Noctilucent clouds, which form from ice particles at high altitudes (about 83 km) and enhance sky brightness after sunset, can be used to trace processes in the atmosphere—the wavy forms of the clouds can give clues about the dynamical processes in the a... (Geophysical Research Letters) [more]
Fine aspherical ash source of Eyjafjallajökull volcano's influence (4 January 2012)
The 2010 eruption of Eyjafjallajökull volcano was not a large event. Over months of volcanic activity the ash plume never pushed above 10 km, and the mass flows peaked at 1 million kg s-1, feeble amounts compared to some other volcanic eruption... (Journal of Geophysical Research - Solid Earth) [more]
Quantifying ice sheet flow characteristics (31 December 2011)
Advances have been made in describing ice sheet motion, but in situ rheology (characteristics that affect the flow) of the ice has been hard to measure in the field. Gillet-Chaulet et al. (2011) show that they can measure ice rheology and strain rates i... (Geophysical Research Letters) [more]
Lunar images alter understanding of impact history (31 December 2011)
New images of the Moon from the Lunar Reconnaissance Orbiter could change our view of the history of impacts on the Moon. In 1972 the Apollo 17 mission took samples from the region of the Serenitatis impact basin. Scientists believed that the impact that creat... (Journal of Geophysical Research - Planets) [more]
Massive salp swarm tilts ocean's chemical balance (31 December 2011)
A surge of nutrients to the warm waters off the southeastern coast of Australia during the highly productive austral spring can spark an explosion in the phytoplankton population. Where phytoplankton bloom, so do the predators that feed on them. Some, like the... (Journal of Geophysical Research - Oceans) [more]
Record Arctic ozone depletion could occur again (30 December 2011)
In the winter of 2010–2011, ozone levels above the Arctic declined to record lows, creating the first Arctic ozone hole, similar to the well-known Antarctic ozone hole. Scientists believe the ozone depletion was due partly to unusually cold temperatures ... (Geophysical Research Letters) [more]
Geological evidence for past earthquakes in Tokyo region (30 December 2011)
In 1923 a magnitude 7.9 earthquake devastated the Tokyo area, resulting in more than 100,000 deaths. About 200 years earlier, in 1703 a magnitude 8.2 earthquake struck the same region, causing more than 10,000 deaths. These earthquakes, which occurred just sou... (Journal of Geophysical Research - Solid Earth) [more]
Estimating hyperconcentrated flow discharge (28 December 2011)
Estimating flow discharge in torrential mountain floods can help in managing flood risk. However, standard methods of estimating discharge have significant uncertainties. To reduce these uncertainties, Bodoque et al. (2011) developed an iterative method... (Water Resources Research) [more]
Pairing simple and complex models could improve predictions (28 December 2011)
Environmental management often relies on complex numerical models. Such models can represent complex natural processes in detail but generally take a lot of computational time to run and even greater computational effort to calibrate. Associating uncertainties... (Water Resources Research) [more]
Traveling supraglacial lakes observed on Antarctic ice shelf (28 December 2011)
A sequence of lakes on top of the George VI ice shelf in Antarctica has been observed to move along the boundary of the ice shelf with Alexander Island. LaBarbera and MacAyeal (2011) analyzed satellite images of the George VI ice shelf in Antarctica tak... (Geophysical Research Letters) [more]
Moored instruments show decadal drop in strength of AMOC (24 December 2011)
The Atlantic branch of the global thermohaline circulation, known as the Atlantic meridional overturning circulation (AMOC), carries warm surface waters to the north and cold water southward along the seafloor, redistributing energy throughout the ocean basin.... (Geophysical Research Letters) [more]
Internal tides measured with multisatellite altimetry (24 December 2011)
Ocean tides flowing over rough topography generate internal tides, which may transport the tidal energy more than 2000 km away from the generation sites. Eventual breaking of these waves produces turbulence and influences the mixing of heat and chemicals, ocea... (Journal of Geophysical Research - Oceans) [more]
Bark beetle outbreaks affect regional carbon cycle (23 December 2011)
Bark beetle outbreaks can kill a large number of trees—in fact, insect outbreaks affect an area similar in size to that affected by forest fires annually across North America. Trees absorb carbon dioxide, so bark beetle outbreaks can significantly affect... (Journal of Geophysical Research - Biogeosciences) [more]
Waste recycling primary source of energy in deep ocean (23 December 2011)
In the dark reaches of the deep ocean, far from the photosynthesizing plants and plankton that fuel life in the surface waters, ecosystems survive on chemical energy. Decades of research on the life that clusters around deep-sea hydrothermal vents has hinted a... (Geophysical Research Letters) [more]
Flows in polar cap ionosphere could trigger auroral substorms (21 December 2011)
Auroral substorms, in which aurora dramatically brighten and become highly dynamic, occur often and seem to be triggered by electric currents in the ionosphere at high latitude. However, scientists do not know the details of how auroral substorms begin and wh... (Journal of Geophysical Research - Space Physics) [more]
Dusty plasma around Enceladus affects Saturn's magnetosphere (20 December 2011)
Scientists have been puzzled by periodic bursts of radiation, known as the Saturn kilometric radiation (SKR), that occur in the planet's magnetosphere. These emissions occur at a rate that is close to, but not quite the same as, the rate at which the planet ro... (Journal of Geophysical Research - Space Physics) [more]
Central California's warm waves a clue to changing coastal currents (20 December 2011)
A quarter of the way up the crest of the California coast, a giant L-shaped headland reaches out to a peak at Point Conception. To the north of the headland, winds blowing off the Pacific Ocean induce strong coastal upwelling, bringing cold ocean water to the ... (Journal of Geophysical Research - Oceans) [more]
Climate has minor influence on mountain river runoff ratios (20 December 2011)
Attempts to predict future water availability are muddled by the tendency of the hydrologic system's key drivers, weather and watershed topography, to change across space and time. Interannual climate variability, land use change, and watershed shape alter how... (Water Resources Research) [more]
Continued volcanic inflation at the Three Sisters (17 December 2011)
As early as the summer of 1996, a 20 × 30 km patch of earth lying just west of the South Sister Volcano started to rise. Joined by the North and Middle sisters, the Three Sisters volcanoes are the most prominent peaks in the central Oregon stretch of the ... (Geochemistry, Geophysics, Geosystems) [more]
Greenland's pronounced glacier retreat not irreversible (16 December 2011)
In recent decades, the combined forces of climate warming and short-term variability have forced the massive glaciers that blanket Greenland into retreat, with some scientists worrying that deglaciation could become irreversible. The short history of detailed ... (Geophysical Research Letters) [more]
Evaluating the global energy balance of Titan (15 December 2011)
To understand the weather and climate on Earth as well as on other planets and their moons, scientists need to know the global energy balance, the balance between energy coming in from solar radiation and thermal energy radiated back out of the planet. The ene... (Geophysical Research Letters) [more]
Methane exceeds nitrous oxide in rivers' contribution to warming (15 December 2011)
Nitrous oxide (N2O) emissions have been the leading area of concern for scientists investigating the role of streams and rivers in global climate change for the past decade. A potent greenhouse gas, nitrous oxide is produced in riverbed sediments th... (Journal of Geophysical Research - Biogeosciences) [more]
Interacting ocean waves explain powerful seafloor canyon flows (14 December 2011)
Off the southwestern coast of Taiwan the Gaoping Submarine Canyon meanders in a giant backwards "S" as it stretches southwestward toward the South China Sea. In the canyon, a 200-m-deep cut into the seafloor that lies 300 m below the sea's surface, the waters ... (Journal of Geophysical Research - Oceans) [more]
Changing Chilean coastal currents could drive aquatic evolution (10 December 2011)
For invertebrate and fish species that spend most of their lives in rich coastal waters rather than migrating freely throughout the open ocean, the formation of island populations and the associated risk of genetic diversity loss are threats to long-term popul... (Journal of Geophysical Research - Biogeosciences) [more]
Internal tides observed to be coherent in shelf sea (10 December 2011)
Internal tides, waves with tidal frequencies below the ocean's surface, contribute to ocean mixing. They are common in shelf seas, shallow marginal seas located on the continental shelf. These tides are believed to be coherent over hundreds of kilometers befor... (Geophysical Research Letters) [more]
Measuring the electron density of the magnetosphere (10 December 2011)
Researchers have demonstrated the potential use of a new way to measure properties of Earth's magnetosphere, the magnetic bubble that surrounds the planet. Zhai et al. (2011) used a property known as Faraday rotation for radio tomographic imaging of the... (Journal of Geophysical Research - Space Physics) [more]
Conflicting accounts of plasmaspheric hiss reconciled (10 December 2011)
Arcing from pole to pole, the Van Allen radiation belts are formed from a large number of protons or electrons trapped high above the Earth, the high-energy particles locked in paths dictated by the terrestrial magnetic field. Separating the outer electron Van... (Journal of Geophysical Research - Space Physics) [more]
Preventing coral bleaching, one hurricane at a time (3 December 2011)
In recent decades, sea surface temperatures, and the occurrence of heat stress in coral communities, have soared. High surface water temperatures lead coral populations to evict their symbiotic, and colorful, algal residents. The photosynthesizing algae are wh... (Geophysical Research Letters) [more]
Using Loch Ness to track the tilt of the world (30 November 2011)
That the rise and fall of the tide is primarily driven by the gravitational pull of the Moon and the Sun is common knowledge, but not all tides are controlled by such a standard mechanism. Researchers working on Loch Ness in Scotland found that rather than Loc... (Journal of Geophysical Research - Oceans) [more]
Expanding shrub range slows Alaskan erosion (30 November 2011)
The relationship between permafrost, Arctic vegetation, soil erosion, and changing air temperatures is complicated at best. For instance, rising temperatures melt surface permafrost layers and increase shrub growth. These shrubs can catch drifting snow, insula... (Journal of Geophysical Research - Biogeosciences) [more]
Reconstructing ocean properties from seismic data (29 November 2011)
Ocean temperature, density, and salinity change with depth on fine scales. Some scientists are beginning to use acoustic images to reconstruct these water column properties. In this technique, acoustic waves are generated in the ocean by an active seismic sour... (Journal of Geophysical Research - Oceans) [more]
Operational seismic network estimates rock slide properties (24 November 2011)
During the spring of 1991, near Randa, Switzerland, two subsequent landslides dropped 30,000,000 m3 of debris on the town below. The rocks dammed the Vispa River, a temporary reservoir that would have failed catastrophically had the army not carved ... (Journal of Geophysical Research - Earth Surface) [more]
New global map of forest canopy height (19 November 2011)
Just how tall are forests around the world? A new global map shows forest canopy height at 1-km spatial resolution. Simard et al. (2011) used satellite data from the Geoscience Laser Altimeter System aboard the Ice, Cloud, and land Elevation Satellite (... (Journal of Geophysical Research - Biogeosciences) [more]
Rhythmic seismic events triggered by ocean noise (19 November 2011)
Seismic events are often detected near volcanoes, but their timing is usually irregular. Stich et al. (2011) detected swarms of regularly repeating long period events at the Deception Island volcano in Antarctica during May–October 2009. Such unu... (Geophysical Research Letters) [more]
Sea ice controls variability in microseismicity (19 November 2011)
When an ocean wave swells, the sudden change in water column mass sends a pressure wave down to the ocean bottom. If the wave lasts long enough to strike the shore, its kinetic energy is transferred to the rock. Both processes induce microseismicity—low-... (Geophysical Research Letters) [more]
Stratospheric ozone affects mesospheric temperature trends (19 November 2011)
Since 1961, temperatures in the summer mesosphere have gone through a series of reversals. From 1961 to 1979 the atmospheric layer that stretches from roughly 50- to 100-km altitude cooled by 0.5 K per decade. In the subsequent 2 decades the rate of cooling es... (Geophysical Research Letters) [more]
When will Antarctic ozone begin to recover? (18 November 2011)
Emissions of ozone-depleting substances have declined over recent decades, but it takes time for the ozone layer to recover. Regular measurements of ozone levels above the South Pole now stretch back 25 years. Hassler et al. (2011) analyzed this recorde... (Journal of Geophysical Research - Atmospheres) [more]
Gravity's effect on landslides: A strike against Martian water (17 November 2011)
A pile of sand, gravel, or other granular material takes on a familiar conical shape, with the slope of the pile's walls coming to rest at the static angle of repose. If the material exceeds this angle, it will trigger an avalanche, tumbling down until it come... (Journal of Geophysical Research - Planets) [more]
Observing volcanic ash plumes and ballistics using Doppler radar (16 November 2011)
When volcanoes erupt, they often emit coarse rocks with ballistic trajectories that fall onto the slopes of the volcano, as well as a plume of fine ash that drifts into the atmosphere. It can be challenging to monitor both simultaneously and discriminate betwe... (Geophysical Research Letters) [more]
Waves triggered by lightning leak out of Earth's atmosphere (16 November 2011)
Lightning flashes can generate electromagnetic waves in the atmosphere. When these waves have a particular frequency, they can resonate in the cavity formed by the Earth's surface and the bottom of the ionosphere. This phenomenon, known as a Schuman resonance,... (Geophysical Research Letters) [more]
Groundwater nitrate pollution in intensively farmed regions (12 November 2011)
Intensified agricultural practices that have developed during the past century have helped improve food security for many people but have also added to nitrate pollution in water supply. Balancing the needs for agriculture and clean groundwater for drinking re... (Water Resources Research) [more]
Pulling regional weather from the climate record (11 November 2011)
At its core, weather is fuelled by the redistribution of energy, and the medium for this regional shuffling is the surface atmosphere. Adjacent air masses are characterized by different physical properties, with atmospheric fronts demarcating the boundaries be... (Geophysical Research Letters) [more]
Scaling law describes Earth's electromagnetic environment (8 November 2011)
The electromagnetic environment surrounding Earth, including the geomagnetic field and atmospheric electric fields, varies on all time scales, but this frequency dependence has not been well studied. Analyzing observations compiled from several published sourc... (Geophysical Research Letters) [more]
Postfire debris flows occur quickly after rainfall starts (5 November 2011)
Areas damaged by forest fires can be vulnerable to debris flows because vegetation is no longer holding dirt and rocks in place, and debris flows in burnt areas can be triggered by much less rainfall than would be needed to trigger a debris flow in an unburned... (Journal of Geophysical Research - Earth Surface) [more]
Identifying sources of methane in the Arctic (5 November 2011)
Methane, a potent greenhouse gas that contributes to climate change, enters the atmosphere from a variety of sources—it can leak from industrial gas fields or pipelines, escape from submarine hydrates that decompose with warming temperatures, or be relea... (Geophysical Research Letters) [more]
Intensifying Pacific trade winds drive regional sea level trends (5 November 2011)
Sea level in the western tropical Pacific Ocean has been increasing at a rate about three times the global average rate of sea level rise, as observed from satellite altimetry and tide gauges. Why are sea level trends so much different in this region? Previous... (Geophysical Research Letters) [more]
Arabian Sea eddies promote seasonal phytoplankton blooms (5 November 2011)
In the Arabian Sea, two phytoplankton blooming periods occur each year, one during the winter northeast monsoon and one during the summer southwest monsoon. It has been established that on the large scale the spatial distribution of the seasonal blooms is driv... (Journal of Geophysical Research - Oceans) [more]
Arctic Ocean tides measured by satellite (4 November 2011)
The Gravity Recovery and Climate Experiment (GRACE) measures Earth's gravity field by gauging the acceleration of two satellites that travel about 220 kilometers apart—slight differences in acceleration between the two satellites provide information abou... (Journal of Geophysical Research - Oceans) [more]
How did Martian polar gullies form? (4 November 2011)
Gullies on Mars have been pointed to as evidence for the presence of flowing liquid water. However, gullies also exist in Mars' polar regions, where temperatures are too low to support liquid water. Other processes have been proposed to explain the origin of g... (Geophysical Research Letters) [more]
Modeling ice stream flow (4 November 2011)
Ice flow speed within an ice sheet can vary from a few meters to thousands of meters per year. Fast flowing ice streams can affect sea level, and their flow variation is one factor that determines whether an ice sheet is gaining or losing mass. But different i... (Journal of Geophysical Research - Earth Surface) [more]
Protactinium-thorium ratio as a proxy for ocean circulation (29 October 2011)
The Atlantic meridional overturning circulation (AMOC) transports water and heat over long distances in the Atlantic Ocean and is believed to have an important effect on Earth's climate. Knowing how strong the AMOC was in the past is essential to understanding... (Geophysical Research Letters) [more]
Forest carbon uptake recovers from modest tree losses (29 October 2011)
By some accounts, forests are currently seeing the highest rates of disturbance since the recession of the Pleistocene glaciers over 10,000 years ago. In recent decades the global extent of forest-disrupting events has increased, yet their intensity has been o... (Journal of Geophysical Research - Biogeosciences) [more]
Glyoxal contribution to aerosols over Los Angeles (28 October 2011)
Laboratory and field studies have indicated that glyoxal (chemical formula OCHCHO), an atmospheric oxidation product of isoprene and aromatic compounds, may contribute to secondary organic aerosols in the atmosphere, which can block sunlight and affect atmosph... (Journal of Geophysical Research - Atmospheres) [more]
Reconciling late Miocene climate and carbon dioxide levels (27 October 2011)
The Miocene epoch, about 23–5 million years ago, was warmer than today. However, reconstructions indicate that it also had levels of atmospheric carbon dioxide (CO2) similar to preindustrial values. Scientists have had difficulty reconciling t... (Geophysical Research Letters) [more]
Subsurface structure affects landslide susceptibility (22 October 2011)
The likelihood of landslides on an exposed bedrock hill is dependent on both the strength of the bedrock and the slope of the hill. In general, stronger rocks provide increased resilience against landslides and are capable of supporting steeper slopes. But for... (Journal of Geophysical Research - Earth Surface) [more]
Measuring carbon uptake by karsts in southwestern China (22 October 2011)
Uptake of carbon (C) by karsts, a type of landscape shaped as water dissolves carbonate bedrock, can be a significant factor in carbon budgets. Yan et al. (2011) measured carbon uptake by karsts in the Houzhai Basin in southwestern China from 1986 to 20... (Journal of Geophysical Research - Biogeosciences) [more]
Winds drive dune movement on Mars (22 October 2011)
Sand dunes, a common feature on the surface of Mars, can provide a record of recent and past changes. Some dunes near Mars' polar areas have been observed to move recently due to carbon dioxide ice sublimation, but it has not been confirmed whether dunes are s... (Geophysical Research Letters) [more]
New map of surface water isotope variation (22 October 2011)
The isotopic composition of hydrogen and oxygen in water varies in waters of different sources, and isotopic composition changes through mixing of water masses and through processes such as evaporation. For instance, the isotope composition in surface water is... (Journal of Geophysical Research - Biogeosciences) [more]
Validating magnetic reconnection model for the magnetopause (22 October 2011)
Originating in the Sun's million-degree corona, the solar wind flows at supersonic speeds into interplanetary space, carrying with it the solar magnetic field. As the solar wind reaches Earth's orbit, its interaction with the geomagnetic field forms the magnet... (Journal of Geophysical Research - Space Physics) [more]
Fractures on curved surfaces: A classic problem solved (20 October 2011)
Sheeting joints, large fractures parallel to a curved rock surface, are common in many locations on Earth, such as the iconic Half Dome in Yosemite National Park in California. Explaining how these fractures form has been a classic unsolved problem in geology.... (Geophysical Research Letters) [more]
Measuring carbon dioxide released from an Amazon lake (20 October 2011)
Lakes in the Amazon basin contain large amounts of organic carbon derived from primary production in the lakes and on land bordering them. Biological oxidation of this organic carbon leads to waters supersaturated in carbon dioxide (CO2) and evasion... (Journal of Geophysical Research - Biogeosciences) [more]
Turbulent diapycnal mixing in the northwestern Pacific (19 October 2011)
Nearly vertical mixing in the oceans across surfaces of constant density (isopycnals), known as diapycnal mixing, transports heat, modifies water masses, and maintains stratification. This mixing needs to be included in models of large-scale ocean circulation ... (Journal of Geophysical Research - Oceans) [more]
Siberian shelf methane emissions not tied to modern warming (19 October 2011)
Eight thousand years ago, a rising sea inundated the vast permafrost regions off the northern coast of Siberia. Comprising the modern east Siberian shelf, the region holds enormous quantities of methane hydrates bottled up in remnant subterranean permafrost zo... (Journal of Geophysical Research - Oceans) [more]
New detail on auroral processes (18 October 2011)
High-resolution imaging from spacecraft is revealing new detail on structures in bright, dynamic auroras. In the auroral regions where particles are accelerated to high energies, dynamic structures evolve on time scales of seconds or less, though the processes... (Geophysical Research Letters) [more]
Using cosmogenic nuclides to quantify pebble abrasion in rivers (15 October 2011)
Sediment transport drives channel erosion and shaping of rivers, so understanding sediment dynamics is a key factor in understanding landscape evolution. Rates of river bedrock erosion depend on the properties of sediment transport, including the grain size di... (Journal of Geophysical Research - Earth Surface) [more]
Seismic quiescence before the 2003 Tokachi-oki earthquake (15 October 2011)
Some studies have found evidence of seismic quiescence, periods with fewer small earthquakes than normal, before the occurrence of some large earthquakes. In a new case study, Katsumata (2011) reexamined data from an earthquake catalog to study seismic ... (Journal of Geophysical Research - Solid Earth) [more]
Freshwater floods drive salt into arid region aquifers (15 October 2011)
For people living in arid ecosystems, groundwater replenished during seasonal flooding is typically their most important source of freshwater. Yet these same floods may also be responsible for temporarily increasing the salinity of the vital freshwater stores,... (Water Resources Research) [more]
Origin of a tidal structure in the thermospheric O/N2 ratio (14 October 2011)
One recently recognized way of studying the ionospheric and thermospheric structure is through measurements of the column number density ratio of atomic oxygen to molecular nitrogen (O/N2). Data from the Global Ultraviolet Imager on board the Thermo... (Geophysical Research Letters) [more]
Heat played key role in Amazon droughts (12 October 2011)
In 2005, the Amazon region suffered a major drought in which a shortage of precipitation affected 2.5 million km2 of land, resulting in significant tree loss. An even more widespread drought hit the region in 2010, affecting 3.2 million m2Geophysical Research Letters) [more]
Color measurements unveil systemic differences in ocean properties (4 October 2011)
Determining the level of biological activity in the ocean is a task not readily suited to satellite-based remote sensing techniques. After all, many important markers of ocean ecosystem health, like nutrient concentrations or population counts of indicator spe... (Journal of Geophysical Research - Oceans) [more]
Clouds not an important control of short-term surface temperatures (1 October 2011)
In two recent papers, R. W. Spencer and W. D. Braswell (Remote Sens., 3(8), 1603–1613, doi:10.3390/rs3081603, 2011) (SB) and R. S. Lindzen and Y.-S. Choi (Asia Pac. J. Atmos. Sci., 47,(4), 377–390, doi:10.1007/s13143-011-0023-x, 2011)... (Geophysical Research Letters) [more]
Models fail to capture Arctic ice thinning, drift trends (29 September 2011)
Observations have shown that Arctic sea ice extent has declined over the past several decades and that this decline has accelerated in recent years. However, climate models used in the Intergovernmental Panel on Climate Change (IPCC) fourth assessment report u... (Journal of Geophysical Research - Oceans) [more]
Small-scale turbulence detected in Mercury's magnetic field (29 September 2011)
With its closest approach a mere 46 million kilometres from the Sun the blast of the solar wind was supposed to wash away any chance that Mercury could hold on to a magnetic field—an idea rejected by the observations of the Mariner 10 spacecraft in 1974.... (Journal of Geophysical Research - Space Physics) [more]
New method improves estimation of subdaily rainfall statistics (24 September 2011)
Daily rainfall data are readily available, but in many locations there are few rain gauges that provide subdaily rainfall data. Hydrologic models often deal with this problem by generating synthetic hourly rainfall series by assuming a temporal scaling behavio... (Water Resources Research) [more]
Small-scale structures observed in Saturn's aurora (22 September 2011)
Observations from the Ultraviolet Imaging Spectrograph Subsystem on NASA's Cassini spacecraft provide new detail on Saturn's aurora. The measurements, reported by Grodent et al. (2011), were made in August 2008 when the spacecraft was only 5 RS<... (Journal of Geophysical Research - Space Physics) [more]
Earthquake data visualization shows ground motion in real time (22 September 2011)
On 11 March 2011 a magnitude 9.0 earthquake shattered the seabed off the eastern coast of Japan's Honshu Island. Visualizations of scientific data showing the peaks of a seismograph or maps overlain with the locations and magnitudes of the earthquake and its n... (Geophysical Research Letters) [more]
Sudden stratospheric warming did not cool the thermosphere (21 September 2011)
In January 2009 a sudden stratospheric warming event occurred, in which temperatures in the stratosphere increased by 70 K. A previous study indicated that this sudden stratospheric warming led to strong cooling higher up in the atmosphere, in the upper thermo... (Geophysical Research Letters) [more]
Thermokarst lakes expand and drain laterally as permafrost degrades (20 September 2011)
In Arctic regions, thermokarst lakes form and expand from thawing permafrost or melting of ice. However, as lakes expand they have a tendency to drain laterally. Jones et al. (2011) surveyed the extent of thermokarst lakes in the continuous permafrost z... (Journal of Geophysical Research - Biogeosciences) [more]
Channel cross-section geometry affects basin response (20 September 2011)
In river networks the shape of a cross section affects streamflow characteristics. Mejia and Reed (2011) developed an analytical framework to study the role of channel and floodplain cross-section geometry in basin-scale hydrologic response. They applie... (Water Resources Research) [more]
Changing climate increases biological productivity in the Arctic (20 September 2011)
Climate change is leading to increased biological productivity in the coastal Arctic. As ice melts and recedes far from land, winds interact with open waters to increase the upwelling of nutrient-rich deep water and stimulate biological productivity. Trembl... (Geophysical Research Letters) [more]
Lakes an important source of carbon emissions (16 September 2011)
Around the world, vast detector networks track the transfer of carbon as it flows through the ecosystem, moving among the atmosphere, terrestrial surface, and organic matter. These carbon flux measurements are integral to understanding the role of various ecos... (Geophysical Research Letters) [more]
Observations improve understanding of the heliosphere (16 September 2011)
The outer regions of the heliosphere, a giant bubble around the solar system created by solar wind, are difficult to study directly. The Interstellar Boundary Explorer (IBEX) mission, which maps emission of energetic neutral atoms from the boundary between the... (Geophysical Research Letters) [more]
Revisiting sea level and energy budgets (16 September 2011)
Various factors contribute to sea level rise, including changing groundwater storage, thermal expansion of the oceans, and melting glaciers and ice sheets. However, studies that add up the observed contributions from these effects have not been able to account... (Geophysical Research Letters) [more]
Finding rates of incorporation of windblown dust into soils (15 September 2011)
As winds blow dust around, a significant amount settles back into terrestrial soils, providing minerals to the soils and affecting soil chemistry and erosion rates. However, the rate at which dust is incorporated into regolith, the loose soil and rock on surfa... (Journal of Geophysical Research - Earth Surface) [more]
An ionospheric precursor to the Tohoku earthquake (15 September 2011)
Most scientists believe that earthquakes are inherently unpredictable, and reports of various kinds of earthquake precursor signals have been difficult to verify. However, in a new study, Heki (2011) reports a possible ionospheric precursor to the devas... (Geophysical Research Letters) [more]
High-resolution peatland photos show change with global warming (15 September 2011)
As global average temperatures rise, vast tracks of peatland currently encased in permafrost will be affected. As the ground thaws, peatlands will evolve in either of two directions. Along one path, land that was previously propped up by supportive permafrost ... (Journal of Geophysical Research - Biogeosciences) [more]
Atmospheric waves break on the Moon's shadow (14 September 2011)
During a solar eclipse the Moon's passage overhead blocks out the majority of the Sun's light, casting a wide swath of the Earth into darkness. The land under the Moon's shadow receives less incoming energy than the surrounding regions, causing it to cool. In ... (Geophysical Research Letters) [more]
Climate model's historical accuracy no guarantee of future success (10 September 2011)
To validate and rank the abilities of complex general circulation models (GCMs), emphasis has been placed on ensuring that they accurately reproduce the global climate of the past century. But because multiple paths can be taken to produce a given result, a mo... (Journal of Geophysical Research - Atmospheres) [more]
Linking Arctic amplification and local feedbacks (10 September 2011)
Climate simulations show that as the Earth warms, the Arctic warms more than the average global warming. However, models differ on how much more the Arctic warms, and although scientists have proposed a variety of mechanisms to explain the Arctic warming ampli... (Geophysical Research Letters) [more]
Maximum entropy method helps study multifractal processes (10 September 2011)
Many natural phenomena exhibit scaling behavior, in which parts of the system resemble the whole. Topography is one example—in some landscapes, shapes seen on a small scale look similar to shapes seen at larger scales. Some processes with scaling behavio... (Geophysical Research Letters) [more]
Predicting interannual variability in evapotranspiration rates (10 September 2011)
The amount of evapotranspiration (ET), the sum of all the water that evaporates from the surface or is drawn up through plants and vented as vapor, is a strong controlling factor for the amount of water left over for other purposes, such as groundwater recharg... (Water Resources Research) [more]
Planktonic foraminifera shells record seasonal temperature changes (9 September 2011)
When planktonic foraminifera calcify, the magnesium to calcium (Mg/Ca) ratios in their shells are sensitive to water temperature. This has enabled paleoceanographers to use Mg/Ca ratios measured from multiple fossil foraminifera shells in sediments as a proxy ... (Paleoceanography) [more]
Building an empirical model of global carbon flux (3 September 2011)
Predicting the behavior of a complex system, like the one that explains the exchange of carbon between the Earth's surface and the atmosphere, by trying to produce theoretical formulations of every environmental process is a daunting challenge. Likewise, the a... (Journal of Geophysical Research - Biogeosciences) [more]
Groundwater depletion's contribution to sea level rise increasing (2 September 2011)
Since the turn of the twentieth century, industrial-scale redistribution of water from landlocked aquifers to the ocean has driven up the global average sea level by over 12 cm. Between 1900 and 2008, roughly 4500 km3 of water was drawn from the gro... (Geophysical Research Letters) [more]
Putting bounds on the drivers of turbulence (30 August 2011)
When fluids with different or continuously varying properties flow next to one another, turbulent flow can emerge. At its most basic, turbulence takes the form of swirling vortices that occur along the flow direction; these vortices are known as a Kelvin-Helmh... (Geophysical Research Letters) [more]
The Last Glacial Maximum's effect on the Walker circulation (26 August 2011)
Over the tropical Pacific Ocean the Walker circulation is an atmospheric flow pattern that runs parallel to the equator, with ascending motion over the western Pacific and a horizontal tropospheric return flow that carries air back to the east. Scientists pred... (Paleoceanography) [more]
Using an artificial brain to interpret Adriatic surface currents (26 August 2011)
Lying between the Italian peninsula and the northwestern Balkan nations, and separated from the Mediterranean Sea by the Strait of Otranto, the Adriatic Sea is largely cut off from global-scale ocean circulation patterns. As a whole, the Adriatic has a permane... (Journal of Geophysical Research - Oceans) [more]
Geomagnetic storms could alter near-Earth radiation environment (25 August 2011)
Potentially hazardous space weather could affect satellites traversing the inner radiation zone, closer to Earth than previously thought, a new study shows. The Earth's radiation belts have a two-layer structure, and it had been thought that most geomagnetic ... (Space Weather) [more]
What controls methanol emissions from grassland? (25 August 2011)
Emission of volatile organic compounds, including methanol (CH3OH), from plants can affect atmospheric chemistry and climate. Seasonal variations such as changes in leaf growth result in changes in atmospheric methanol concentrations. Hörtna... (Journal of Geophysical Research - Biogeosciences) [more]
Arctic air may become cleaner as temperatures rise (24 August 2011)
The air in the Arctic is cleaner during summer than during winter. Previous studies have shown that for light-scattering pollutants, this seasonal cycle is due mainly to summer precipitation removing pollutants from the air during atmospheric transport from mi... (Geophysical Research Letters) [more]
Earthquake-generated landslides are an important control of riverbed erosion (24 August 2011)
River erosion is a powerful shaper of topography, cutting through bedrock and over time converting smooth terrain to rolling hills or jagged cliffs. The rate of bedrock incision is influenced by the stream's slope and width, the water's flow rate, and the p... (Journal of Geophysical Research - Earth Surface) [more]
Observing changes in atmospheric heat content (23 August 2011)
Globally, air temperatures near the surface over land have been rising in recent decades, and this has been presented as solid evidence of global warming. However, some scientists have argued that total heat content (energy), rather than temperature, should be... (Geophysical Research Letters) [more]
How ocean ridges affect large-scale ocean circulation (23 August 2011)
Driving the flow of heat and nutrients around the ocean is the meridional overturning circulation, a large-scale current system that in the Atlantic Ocean carries warm surface waters northward and cold, dense water to the south along the bottom of the ocean. A... (Journal of Geophysical Research - Oceans) [more]
Study suggests Arctic sea ice loss is not irreversible (20 August 2011)
The Arctic has been losing sea ice as Earth's climate warms, and some studies have suggested that the Arctic could reach a tipping point, beyond which ice would not recover even if global temperatures cool down again. However, a new study by Armour et alGeophysical Research Letters) [more]
Predicting space climate change (19 August 2011)
Galactic cosmic rays and solar energetic particles can be hazardous to humans in space, damage spacecraft and satellites, pose threats to aircraft electronics, and expose aircrew and passengers to radiation. A new study shows that these threats are likely to i... (Geophysical Research Letters) [more]
All channel networks share some properties (18 August 2011)
Channel networks transport water through a catchment and play a key role in hydrology. Understanding the network properties can be useful, so Moussa et al. (2011) developed a model to calculate the morphometric properties of catchments. They found some ... (Water Resources Research) [more]
Carbonate reefs may have triggered a bout of global cooling (17 August 2011)
Earth's history shows a steady stream of extreme climatic change, spanning everything from planet-engulfing glaciers to tropical conditions near high latitudes. These large climate shifts are often attributed to permanent changes: the opening of a new waterway... (Paleoceanography) [more]
Estimating adsorbed water film thickness in unsaturated soil (17 August 2011)
In saturated soil, water fills every crack and crevice between the individual grains of dirt. As the water evaporates or drains away, some water can become trapped between soil particles by capillary pressure or be adsorbed onto the surface of the grains in ex... (Water Resources Research) [more]
UV solar irradiance was low during recent solar minimum (16 August 2011)
Solar irradiance, which varies with the 11-year solar cycle and on longer time scales, can affect temperature and winds in the atmosphere, influencing Earth's climate. As the Sun currently wakes up from a period of low sunspot activity, researchers want to kno... (Journal of Geophysical Research - Atmospheres) [more]
Magnetic field data suggest thin atmosphere on Saturn's moon Dione (12 August 2011)
A new study indicates that one of Saturn's moons, Dione, probably has a tenuous atmosphere. NASA's Cassini spacecraft has conducted only two close flybys of Dione. Magnetic field observations from one of those flybys, described by Simon et al., (2011) s... (Geophysical Research Letters) [more]
Ultraviolet and infrared observations of Saturn's auroral oval (10 August 2011)
New observations of Saturn's southern auroral oval made simultaneously in ultraviolet (UV) and infrared (IR) wavelengths show how complex and dynamic the auroral oval is. Melin et al. (2011) present high-spatial-resolution observations from the Cassini ... (Geophysical Research Letters) [more]
Dikes provide insight into early history of Mars (5 August 2011)
New observations from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) show the presence of multiple magmatic intrusions in the Valles Marineris canyon on Mars. Flahaut et al. (2011) determined the composition of these dikes using CRISM ... (Geophysical Research Letters) [more]
Observations of abyssal flow and mixing (5 August 2011)
Scientists once thought the abyssal ocean, near the ocean bottom, was nearly stagnant, but recent observations show it is quite dynamic, and abyssal mixing plays an important role in the general circulation. Contributing to understanding of abyssal flow, Al... (Geophysical Research Letters) [more]
"Great Calcite Belt" encircles Southern Ocean (4 August 2011)
Coccolithophores, a type of single-celled phytoplankton, produce 2-μm-diameter carbonate shells known as coccoliths. The distribution of coccolithophores is influenced by nutrient availability and physical stratification of the ocean. Moreover, their abil... (Journal of Geophysical Research - Oceans) [more]
Was ocean acidification responsible for history's greatest extinction? (2 August 2011)
Two hundred and fifty million years ago, the world suffered the greatest recorded extinction of all time. More than 90% of marine animals and a majority of terrestrial species disappeared, yet the cause of the Permian-Triassic boundary (PTB) die-off remains un... (Paleoceanography) [more]
Farmers' past choices enhance mitigation potential of reforestation (2 August 2011)
Land cover changes such as clearing forests to create farmland influence climate not only by changing the amount of carbon dioxide (CO2) absorbed by the vegetation but also by changing the albedo, the fraction of sunlight reflected back to space. Th... (Geophysical Research Letters) [more]
Examining nitrogen isotope ratios as a paleoproxy (2 August 2011)
The relative consumption of nutrients by diatoms in the ocean, with regard to both supply and demand of nitrate, affects the nitrogen isotope composition of diatoms. Sedimentary nitrogen isotope ratios are often used as a proxy for past conditions. However, th... (Paleoceanography) [more]
Potential solution to the cool tropics paradox (30 July 2011)
The "cool tropics paradox" has been a thorn in the side of paleoclimate researchers, who draw on diverse techniques to improve their estimates of ancient climates. For the early Paleogene, between approximately 56 and 49 million years ago, atmospheric reconstr... (Paleoceanography) [more]
First map of sea ice production in Arctic coastal polynyas (29 July 2011)
In Arctic coastal polynyas, persistent areas of thin ice, a large amount of new ice forms during the winters. Significant heat is lost through these regions of thin ice. Knowing how much ice is produced in polynyas is important for determining overall cold sal... (Journal of Geophysical Research - Oceans) [more]
Exploring the effects of climate change on northern soil carbon (28 July 2011)
Over recent millennia, northern ecosystems have been an important sink for the global carbon cycle, with vast quantities of carbon slowly accumulating and becoming trapped within thick layers of permafrost or peat. Some scientists have raised the prospect that... (Journal of Geophysical Research - Biogeosciences) [more]
Slowly but steadily, a stormier Europe (26 July 2011)
One anticipated consequence of global warming is a rise in the strength and frequency of wind storms striking Europe, bringing about associated increases in property damage, choppy seas, and coastal flooding. Previous research, mostly based on long-term pressu... (Geophysical Research Letters) [more]
Martian soil oxidation-reduction potential not too extreme for life (23 July 2011)
Ever since the NASA Viking mission, which reached Mars in 1976, there has been considerable interest in the composition of Martian soils. Some Viking measurements indirectly suggested that the soils contained highly oxidizing compounds, which could present ext... (Geophysical Research Letters) [more]
High-resolution model reproduces heliospheric current sheet fold (23 July 2011)
Spewing from the Sun, magnetic field lines are carried by the solar wind to the outer reaches of the solar system. Crossing over the extended reach of the Sun's equator, these magnetic field lines turn inward toward the Sun's opposite hemisphere. Particularly ... (Geophysical Research Letters) [more]
Refining the relationship between ocean color and salinity (23 July 2011)
In the age of satellite sensors, ocean surface salinity detections have remained an elusive, yet important, property. Rivers discharge massive quantities of fresh water to the oceans every year, changing surface salinities and altering ocean circulation patter... (Journal of Geophysical Research - Oceans) [more]
Sources and sinks of methane in Lake Kivu (22 July 2011)
Africa' s Lake Kivu, which borders Rwanda and the Republic of the Congo, contains huge amounts of methane (an estimated 60 km3) as well as carbon dioxide (an estimated 300 km3). Although the methane could provide a source of energy if... (Journal of Geophysical Research - Biogeosciences) [more]
Thermal expansion not a major source of sea level rise (21 July 2011)
With the power to drown low-lying nations, destroy infrastructure, and seriously affect sensitive coastal ecosystems, sea level rise may be one of the most readily apparent consequences of global warming that is already under way. The sources of, and dynamics ... (Geophysical Research Letters) [more]
Explaining the cause of asymmetry in the electron foreshock (21 July 2011)
As the solar wind nears the edge of Earth's magnetosphere, it creates a bow shock, a region in which the solar wind speed drops abruptly. Some solar wind electrons bounce off the bow shock; these reflected electrons interact with oncoming solar wind in a regio... (Geophysical Research Letters) [more]
Global cyclone activity historically low (20 July 2011)
A new research study shows that overall global tropical cyclone activity has decreased to historically low levels during the past 5 years. Maue (2011) analyzed global tropical cyclone data from 1970 through May 2011 to examine the considerable interanna... (Geophysical Research Letters) [more]
Miniature detector measures deep space radiation (14 July 2011)
The 1972 journey of Apollo 17 marked not only the last time a human walked on the Moon but also the most recent manned venture beyond the outer reaches of the Earth's atmosphere. With preparations being made for humans to once again explore deep space, importa... (Space Weather) [more]
Deep ocean heat content is key to estimating Earth's radiation balance (14 July 2011)
Despite the fact that average temperatures on land have been increasing from year to year, globally averaged surface temperatures from 2000 to 2010 have shown only moderate warming. This is because sea surface temperatures over the past decade have been flat, ... (Geophysical Research Letters) [more]
Melting glaciers can change Earth's gravity field (13 July 2011)
The Earth's rotation causes mass from the ductile mantle to bulge at the equator, making the radius of the Earth about 21 km larger at the equator than at the poles. Over the past 20,000 or so years, the Earth has been becoming more round as it adjusts to the ... (Geophysical Research Letters) [more]
Cocos plate gravity lineaments due to thermal contraction cracks (13 July 2011)
Gravity lineaments, narrow stripes of stronger gravity, were first observed on the ocean floor in the south central Pacific several decades ago, but scientists still debate their origin. Because the south central Pacific gravity lineaments align with the tecto... (Geochemistry, Geophysics, Geosystems) [more]
Tremor activity changes following two San Andreas Fault earthquakes (12 July 2011)
Large earthquakes change the stress on faults. This can either accelerate or decelerate deep fault creep, as suggested by changes in tremor activity rates. Analyzing tremor data from the San Andreas Fault in central California, Shelly and Johnson (2011)... (Geophysical Research Letters) [more]
Classifying freakish and nonfreakish days on the ocean (12 July 2011)
Freak waves—ocean waves more than twice the average wave height—can rise up without warning on otherwise calm seas. Because they can arise suddenly and be quite large, these waves, also known as rogue waves, present a danger to ships. To work towar... (Geophysical Research Letters) [more]
New watershed classification based on distance to the drainage divide (11 July 2011)
Models of watershed behavior are beginning to incorporate lidar (light detection and ranging) topography measurements with resolutions of the order of 1 m2, but this increase in the availability of high-quality data is outpacing the ability to make ... (Water Resources Research) [more]
Potential for resumption of East Pacific sea level rise after 30-year hiatus (8 July 2011)
Over the course of the past century the global rate of sea level rise has increased threefold, jumping from 1 mm yr-1 in the early 1900s to 3 mm yr-1 in the late twentieth century. This seemingly small increase in the global average can h... (Journal of Geophysical Research - Oceans) [more]
Shrinking Alpine glaciers spell trouble for Europe's rivers (8 July 2011)
Within the frosted peaks of the Swiss Alps, the cycle of winter precipitation accumulation and springtime melt provides a seasonal flow of water to much of western Europe. Research into the freshwater contributions of Alpine glaciers has predominantly looked t... (Water Resources Research) [more]
Chlorine radicals measured in Eyjafjallajökull volcanic plume (2 July 2011)
When the Icelandic volcano Eyjafjallajökull erupted in spring 2010, it disrupted commercial air travel, stranding passengers across Europe and beyond. In response to the lack of information on the volcanic ash load and dispersion, scientific instruments w... (Geophysical Research Letters) [more]
Magnetic behavior transitions identified in natural rock formations (2 July 2011)
How the magnetic properties of minerals such as magnetite change with grain size is of fundamental importance to understanding magnetic fields of the past and present, which are useful for tracking the movement of tectonic plates and in teasing out the histori... (Geochemistry, Geophysics, Geosystems) [more]
New data refine the travels of Gondwana (1 July 2011)
The supercontinent Pangea, which roughly 300–200 million years ago existed as the only landmass on Earth, plays a special role in the history of geophysics. The geological, biological, and paleontological similarities between now distant shores—onc... (Geochemistry, Geophysics, Geosystems) [more]
Tohoku earthquake shook the ionosphere (28 June 2011)
The giant 11 March 2011 magnitude 9 Tohoku earthquake not only shook the Earth and caused devastating tsunamis but also rattled the ionosphere, according to a new study. The surface seismic waves and tsunamis triggered waves in the atmosphere. These atmospheri... (Journal of Geophysical Research - Space Physics) [more]
Severe 2010 Amazon drought in historical context (22 June 2011)
In 2005 a severe "once in a century" drought struck the Amazon rain forest. Just 5 years later, an even more severe and widespread drought struck the region. How do these extreme events fit into the context of historical droughts? Marengo et al.Geophysical Research Letters) [more]
Ocean floor faulting explains differences in Central American lavas (22 June 2011)
Off the west coast of Central America lies the Cocos tectonic plate. The plate's steady eastward progression forces it under the Caribbean and North American plates, driving seismic and volcanic activity. Along the Central American coast, the chemical content ... (Geochemistry, Geophysics, Geosystems) [more]
Currents can be driven in the polar ionosphere (21 June 2011)
Ionospheric heaters induce controlled modifications in the ionosphere, whose study allows better understanding of effects driven naturally by solar activity in the ionosphere and the radiation belts. Previous ionospheric heaters at the Earth's poles have ... (Geophysical Research Letters) [more]
High detail snapshots of rare gigantic jet lightning to the ionosphere (21 June 2011)
In the ionosphere, more than 80 km above Earth's surface, incoming radiation reacts with the thin air to produce highly charged ions, inducing an electric potential between the ionosphere and the surface. This charge difference is dissipated by a slow leak fro... (Geophysical Research Letters) [more]
Model gives 3 months warning of Amazonian forest fires (17 June 2011)
In the summer of 2005 the Amazon rainforest suffered widespread drought, being heralded at the time as the drought of the century. Because of the dehydrated conditions, supplemented by slash and burn agricultural practices, the drought led to widespread forest... (Geophysical Research Letters) [more]
Ozone depletion leading force for Southern Ocean change (16 June 2011)
Previous studies have suggested that key aspects of the Southern Ocean are affected by elevated atmospheric carbon dioxide levels. Increasing greenhouse gas (GHG) concentrations, which strengthen surface winds over much of the Southern Ocean, may increase flow... (Geophysical Research Letters) [more]
Agricultural drainage affects export of dissolved organic carbon (16 June 2011)
Dissolved organic carbon (DOC) exported from agricultural lands can affect watershed carbon budgets and aquatic ecosystem functions. Agricultural practices, especially enhanced drainage, which is widespread in the midwestern United States and expanding, can in... (Journal of Geophysical Research - Biogeosciences) [more]
Estimating contaminant spreading by subsurface water (16 June 2011)
Spills of fuels, solvents, and solid waste continually emit pollutants into groundwater, the major source of drinking water for most of the world. These contaminants can react with dissolved oxygen or other chemicals present in groundwater, leading to natural ... (Water Resources Research) [more]
Did Aboriginal vegetation burning affect the Australian summer monsoon? (15 June 2011)
For thousands of years, Aboriginal Australians burned forests, creating grasslands. Some studies have suggested that in addition to changing the landscape, these burning practices also affected the timing and intensity of the Australian summer monsoon. Differe... (Geophysical Research Letters) [more]
Episodic tremor triggers small earthquakes (15 June 2011)
It has been suggested that episodic tremor and slip (ETS), the weak shaking not associated with measureable earthquakes, could trigger nearby earthquakes, however, this had not been confirmed until recently. Vidale et al. (2011) monitored seismicity in ... (Geochemistry, Geophysics, Geosystems) [more]
Measuring properties of contrails to estimate their effects on climate (14 June 2011)
Condensation trails, or so-called contrails, formed by freezing of ice crystals in the exhaust from aircraft jet engines could affect climate. Like natural cirrus clouds, contrails change atmospheric temperatures not only by blocking sunlight from reaching the... (Geophysical Research Letters) [more]
Determining the trigger of East Asian dust storms (10 June 2011)
In the past 2 decades, there has been a dramatic increase in the occurrence of dust storms over East Asia. The trigger for this increase has been elusive because the ability of gusting wind to whip up a dust storm depends on a large number of factors, ranging ... (Geophysical Research Letters) [more]
Next generation atmospheric model improves hurricane forecasting (7 June 2011)
Accurately predicting hurricane development from one season to the next is a problem that crosses multiple temporal and spatial scales. The driving force behind the overall activity level for a year depends on broad climate dynamics, such as the El Niño... (Geophysical Research Letters) [more]
Constraining the trigger for an ancient warming episode (7 June 2011)
The Paleocene epoch (approximately 66–56 million years ago) was sandwiched between sudden climate shifts and mass extinctions. The boundary between the end of the Paleocene and the beginning of the Eocene (P-E boundary) saw the global average temperature... (Geochemistry, Geophysics, Geosystems) [more]
How Indonesian development destroyed Australia's rainforest (1 June 2011)
Just over 3 million years ago, a climatic upheaval forever changed Australia's western coast. Over the span of 200,000 years the southward flowing waters of the Leeuwin Current cooled by 2°–3°C, decreasing coastal precipitation and converting nor... (Paleoceanography) [more]
Seasonal anomalies in the Canary Current (1 June 2011)
Along the northwestern coast of Africa lies an important fishery, stimulated by an upwelling of cold, nutrient-rich, deep-ocean water. Driven by a complex convergence of ocean currents, the waters between the coast, the Portuguese island of Madeira, and the Ca... (Journal of Geophysical Research - Oceans) [more]
Ion-ion hybrid Alfvén wave resonator demonstrated (1 June 2011)
Theoretical calculations have indicated that in magnetized plasmas with two ion species, Alfvén waves, oscillations of the magnetic field due to plasma currents, can become trapped in a resonator. Now such a resonator has been demonstrated for the first ... (Geophysical Research Letters) [more]
The effect of sediment on mountain river erosion (1 June 2011)
Mountain uplift and subsequent water-powered erosion are powerful and persistent processes shaping the landscape, and understanding the interactions between these two processes has been an area of active research for the past 2 decades. The rate of river erosi... (Journal of Geophysical Research - Earth Surface) [more]
Estimating the distribution of extreme events (28 May 2011)
Modeling the distribution of extreme events such as major floods, severe rainfall, and high wind speeds can be challenging. Researchers in many fields commonly use the generalized extreme value (GEV) distribution to characterize how these events are distribute... (Water Resources Research) [more]
Explaining away El Niño Modoki (27 May 2011)
The traditional view of El Niño is that it starts with a warm sea surface anomaly off the west coast of South America. This aberrant warming drifts west from the coast, triggering peak sea surface temperatures in the central Pacific during the southern ... (Geophysical Research Letters) [more]
Surge in North Atlantic hurricanes due to better detectors, not climate change (26 May 2011)
A spate of research has indicated there may be a link between climate change and the prevalence of North Atlantic tropical cyclones. Upon closer inspection, however, researchers have noted that the prominent upswing in tropical cyclone detections beginning in ... (Journal of Geophysical Research - Atmospheres) [more]
El Niño–Southern Oscillation variability persisted in warmer world (26 May 2011)
Changes in the distribution of sea surface temperature associated with the El Niño–Southern Oscillation (ENSO) cause significant changes in weather. In the past 40 years it has been observed that the frequency and intensity of El Niño event... (Paleoceanography) [more]
Calculating specific catchment area (25 May 2011)
Specific catchment area, defined as the area of land upslope of a width of contour, divided by the contour width, is a commonly used quantity in hydrology to describe complex terrain for analyzing water flow on hill slopes; it can be a surrogate for water disc... (Water Resources Research) [more]
Measuring the air content of the Larsen Ice Shelf (25 May 2011)
The surface elevation of the Larsen Ice Shelf in the Antarctic Peninsula has lowered by about 0.1 m yr–1 since 1992. This could be caused either by an increase in the density of firn (compacted snow) at the surface of the ice shelf or by an in... (Geophysical Research Letters) [more]
Potential for Atlantic current collapse confirmed by global circulation model and observations (25 May 2011)
The Atlantic meridional overturning circulation (AMOC) is a gigantic heat, salt, and nutrient mixer that spans the length of the Atlantic Ocean. Drawing warming surface waters up from the south through the Gulf Stream and along the North Atlantic Current, the ... (Geophysical Research Letters) [more]
Simulating observations of solar irradiance (24 May 2011)
Rising concentrations of carbon dioxide and other greenhouse gases in the atmosphere change how much solar radiation is reflected back into space. A proposed NASA mission, Climate Absolute Radiance and Refractivity Observatory (CLARREO), would make benchmark m... (Journal of Geophysical Research - Atmospheres) [more]
Satellite measurements of hydrogen sulfide in a volcanic plume (24 May 2011)
For the first time, satellite measurements have been made of hydrogen sulfide (H2S) in a volcanic plume. Volcanoes release (H2S) in large quantities—yearly global estimates range from 1 to 37 Tg. Along with sulfur dioxide (SO2<... (Geophysical Research Letters) [more]
Improving model estimates of gross primary production (18 May 2011)
Balancing the global carbon budget is a daunting task complicated by the fact that even the most essential values elude direct observation. Gross primary production, the amount of carbon used by terrestrial vegetation to fuel its annual growth, is often estima... (Journal of Geophysical Research - Biogeosciences) [more]
The global virtual water trade network (17 May 2011)
While some countries have substantial supplies of freshwater, others need to import water to sustain their populations. Because food products contain significant amounts of water, global trade in food effectively moves water from one country to another in a "v... (Water Resources Research) [more]
Formation of oil and gas intrusions after the Deepwater Horizon oil spill (12 May 2011)
After the Deepwater Horizon oil spill in 2010, hydrocarbons were released into the Gulf of Mexico. These hydrocarbons were found to have formed large subsurface horizontal intrusions. Socolofsky et al. (2011) studied the dynamics of the formation of the... (Geophysical Research Letters) [more]
Ice sheet collapse affects ocean circulation (11 May 2011)
As Earth's climate warms and ice melts, freshwater input to oceans could weaken the large-scale Atlantic meridional overturning circulation, which acts as an important conveyor of heat and has significant effects on climate. Green et al. (2011) used an ... (Paleoceanography) [more]
Agricultural chemical export dynamics in a watershed (11 May 2011)
Understanding how agricultural chemicals filter through a catchment is important for managing water quality. Using a concept of the catchment as a physicochemical filter, Guan et al. (2011) examined nitrate, phosphate, and atrazine loads in the Little V... (Water Resources Research) [more]
Improving global estimates of land surface properties (11 May 2011)
Large models often rely on numerical simplifications of complex or small-scale processes, usually because the underlying mechanisms are not well understood or direct observations are unavailable. The values for these parameterizations can be tuned to fit obser... (Journal of Geophysical Research - Atmospheres) [more]
Hydroclimatic mechanisms of cholera transmission in the Bengal Delta (10 May 2011)
Cholera, a deadly waterborne disease, remains a major threat in many areas of the world, including the Bengal Delta region. In this region, cholera outbreaks have two annual peaks; the first occurs during the dry season in the spring, and the second occurs in ... (Water Resources Research) [more]
Mapping the magnetic mayhem in the heliosheath (10 May 2011)
When Voyager 1 passed into the heliosheath in 2004, it became the first man-made object to explore the remote edge of the Sun's magnetic influence. The heliosheath, between 1.5 and 15 billion km thick and starting roughly 14 billion km from the Sun, is where t... (Journal of Geophysical Research - Space Physics) [more]
Tropical atmospheric circulation and precipitation changing (7 May 2011)
As Earth's climate has warmed over the past several decades, atmospheric and hydrological cycle changes are being observed globally and regionally. For instance, Zhou et al. (2011) analyzed trends in the hydrological cycle in the tropics over the past 2... (Journal of Geophysical Research - Atmospheres) [more]
Earlier Arctic snowmelt does not increase carbon sequestration (7 May 2011)
Snow has been melting earlier in the spring in the Arctic in recent years, and this earlier melting is predicted to continue as the Arctic continues to warm. Some studies have suggested that earlier snowmelt, which can lead to longer growing seasons and increa... (Geophysical Research Letters) [more]
Part of the Gulf of Mexico became greener after oil spill (3 May 2011)
Biological changes have been observed in the northeastern Gulf of Mexico since the April–July 2010 Deepwater Horizon oil spill, the largest offshore spill event in U.S. history. To overcome the difficulty of lack of sufficient field sampling data for a r... (Geophysical Research Letters) [more]
Lightning not detected on Titan (28 April 2011)
Scientists have speculated that lightning on Saturn's moon Titan could produce changes in atmospheric chemistry and could even spark production of organic compounds that could be precursors for evolution of life, but so far there has been no conclusive detecti... (Geophysical Research Letters) [more]
New ice core record of atmospheric methane (28 April 2011)
Atmospheric concentrations of methane, an important greenhouse gas, have varied in the past on time scales ranging from seasons to hundreds of thousands of years. Understanding past variations is important to interpreting current natural and anthropogenic chan... (Journal of Geophysical Research - Biogeosciences) [more]
Cold snaps still a threat despite global warming (27 April 2011)
Long stretches of extreme cold weather can cause serious damage to agriculture as well as transportation, water, and energy infrastructure. Cold snaps have the potential to kill, with deaths attributed to cold weather often outpacing those caused by extreme he... (Geophysical Research Letters) [more]
Phytoplankton affect clouds and precipitation (26 April 2011)
Phytoplankton in the ocean produce the gases dimethyl sulfide and isoprene, which can enter the atmosphere. To find out how this affects cloud properties and precipitation, Krüger and Graßl (2011) analyzed a variety of satellite observations o... (Geophysical Research Letters) [more]
Fundamental issues of modeling in a climate of change (22 April 2011)
Numerical models, one of the dominant modes of performing scientific research, fit into two broad classes: operational models, which aim to produce tightly constrained estimates of future behavior using historical observations, and exploratory, or novelty-seek... (Water Resources Research) [more]
Statistical model predicts shoreline erosion rates due to sea level rise (22 April 2011)
While sea level rise in the face of global warming is a well-acknowledged threat, providing estimates of the local impact—the information needed by planners to develop effective strategies against the rising waters—has been difficult. Many attempts... (Journal of Geophysical Research - Earth Surface) [more]
Modeling monthlong slow slip earthquakes (21 April 2011)
The slow crawl of the Earth's tectonic plates is periodically punctuated by the release of decades or centuries of accumulated stress. Standard earthquakes, lasting from fractions of a second to minutes in duration, are known to range from imperceptible to tho... (Geochemistry, Geophysics, Geosystems) [more]
A new source of freshwater for Antarctica's coastal waters (20 April 2011)
Over the past several decades, research into submarine groundwater discharge (SGD), predominantly regarding its prevalence as a source of freshwater and nutrients to coastal ecosystems, has grown in prominence. Using a newly developed groundwater discharge sen... (Geophysical Research Letters) [more]
Modeling flow pathways through pores and cracks in aerated soils (19 April 2011)
Knowledge of how chemical contaminants spread through soil is of vital importance to those who manage groundwater and agricultural resources, superfund sites, landfills, and mines. Of particular interest to contaminant transport studies is crop management&mdas... (Water Resources Research) [more]
Sea surface height and steric height increases in the Southern Hemisphere (16 April 2011)
Sea surface height has increased by 3 mm yr-1, globally averaged, since 1993. Some fraction of sea surface height change is due to added water, for instance, from melting glaciers, and some is due to increasing heat and salinity changes (steric effe... (Geophysical Research Letters) [more]
Multidecadal variability of the North Brazil Current (15 April 2011)
The Atlantic meridional overturning circulation (AMOC), which carries warm water to high northern latitudes near the surface and returns cold water in the deep ocean to the Southern Hemisphere, affects and is affected by global climate change. There has been d... (Journal of Geophysical Research - Oceans) [more]
Coastal cooling and marine productivity increasing off Peru (14 April 2011)
The upwelling system off Peru is of environmental and economic importance due to its high fish productivity. It has been suggested that global warming may be leading to increasing temperature differences between the coast and the ocean, causing increases in al... (Geophysical Research Letters) [more]
Aircraft measured oil evaporating from Gulf oil spill (14 April 2011)
Following the Gulf of Mexico oil spill in April 2010, some hydrocarbons dissolved in the ocean, while other leaked hydrocarbons that did not dissolve evaporated into the atmosphere. Ryerson et al. (2011) describe airborne in situ measurements of the hydrocarbo... (Geophysical Research Letters) [more]
Can the cultivation of microalgae meet U.S. energy demands? (13 April 2011)
As biofuels such as ethanol and esters become increasingly attractive alternatives to nonrenewable resources such as oil and coal, scientists have become interested in determining the feasibility of biofuels to help meet U.S. energy demands in light of governm... (Water Resources Research) [more]
Building an atlas of Arctic climate dynamics (12 April 2011)
The oceans and atmosphere act as a giant heat mixer. However, they do not spread energy evenly across the planet—the overall effect is a net poleward transfer of energy. While it is known that this energy is predominantly moved by traveling air packets a... (Journal of Geophysical Research - Atmospheres) [more]
Using regional wind-inducing circulation patterns to estimate future rainfall (12 April 2011)
The complex connections that drive Earth's changing climate are most easily understood on a broad scale, where rising temperatures, changing precipitation patterns, and shifting greenhouse gas concentrations can be examined through changes in the statistical a... (Water Resources Research) [more]
Could the cold winter of 2009–2010 have been predicted? (9 April 2011)
In parts of North America and Europe the winter of 2009–2010 was one of the coldest and snowiest in recent history. These extreme weather patterns were likely the result of the strongly negative phase of the North Atlantic Oscillation (NAO). Researchers ... (Geophysical Research Letters) [more]
Amazon region became less green due to 2010 drought (8 April 2011)
The Amazon region became significantly less green due to a severe 2010 drought. Xu et al. (2011) analyzed satellite-based measurements to compare the greenness of Amazon vegetation due to the 2010 drought to that due to a severe drought in 2005. They found tha... (Geophysical Research Letters) [more]
Rainfall variability increasing in northern Australia (6 April 2011)
Rainfall variability, including the frequency of extreme floods and droughts, is increasing in northeastern Australia, a new study shows. Rainfall in Queensland is very variable from year to year, partly due to El Niño-Southern Oscillation (ENSO) events. ... (Paleoceanography) [more]
Variability of the East Greenland–Irminger Current (1 April 2011)
The East Greenland–Irminger Current (EGIC), which flows southwestward along the eastern coast of Greenland, is important because variability in the EGIC likely influences convection in the Labrador and Irminger seas and could affect the global meridional... (Geophysical Research Letters) [more]
Carbon in Earth's core (1 April 2011)
The Earth's dense core consists primarily of iron, but seismological data and mineral physics results show that the inner core is lighter than pure iron by 3–7% and the outer core is lighter than pure iron by 5–10%, so the core must also contain so... (Journal of Geophysical Research - Solid Earth) [more]
Identifying misbehaving models using baseline climate variance (1 April 2011)
The majority of projections made using general circulation models (GCMs) are conducted to help tease out the effects on a region, or on the climate system as a whole, of changing climate dynamics. Sun et al., (2011) however, used model runs from 20 diff... (Water Resources Research) [more]
Floodplain dynamics included in river model (1 April 2011)
Surface water flow is important to the climate system and to water resources management. Floodplain inundation dynamics are a key part of surface water flow, but most current river routing models do not include realistic representation of floodplain dynamics. ... (Water Resources Research) [more]
Modeling saturation overshoot in porous media (29 March 2011)
Infiltration of water into soils or porous rocks often proceeds in unpredictable, preferential flow paths, also known as fingers. These fingers are caused by a condition called saturation overshoot, where the water content in the finger tip is greater than the... (Water Resources Research) [more]
Understanding the behavior of mercury in the cryosphere (24 March 2011)
Anthropogenic emission of mercury is increasing, especially in Asia. Mercury in the atmosphere can be deposited into the cryosphere, regions covered by snow and ice. Some of the mercury deposited into the cryosphere is emitted back to the atmosphere, and some ... (Journal of Geophysical Research - Atmospheres) [more]
The cause of the 2010 Russian heat wave was largely predictable (23 March 2011)
From June to August 2010, a stable high-pressure air mass hung in the sky over western Russia. This episode of "atmospheric blocking" drove up temperatures, causing thousands of deaths and breaking temperature records across the country. Strong heat waves like... (Geophysical Research Letters) [more]
Observing nonlinear internal waves over New Jersey's continental shelf (23 March 2011)
Nonlinear internal waves, which occur below the ocean's surface, can influence coastal environments, for instance, through increased turbulent mixing that affects fluxes of nutrients and heat. The details of how these waves are generated are not well understoo... (Journal of Geophysical Research - Oceans) [more]
How North Atlantic cooling alters Southern Ocean wind and increases atmospheric carbon dioxide (23 March 2011)
At least seven times during the last ice age, large portions of the polar glaciers crumbled, sending rafts of ice floating into the North Atlantic Ocean. When these icebergs melted, the resultant injection of cold, fresh water was enough to drive down ocean te... (Paleoceanography) [more]
Deadly 2010 Russian heat wave not a consequence of climate change (19 March 2011)
Although some people may try to ascribe specific extreme weather events to climate change, global warming cannot be held responsible for recent weather events such as the 2010 Russian heat wave. Using climate simulations and a comparison against historical con... (Geophysical Research Letters) [more]
Ash from huge Australian bushfires in 2009 circled the globe (19 March 2011)
On 7 February 2009, record high temperatures, low rainfall and humidity, and fast blowing winds caused sparks in the bush near the Australian city of Melbourne to ignite much of the southeastern region of the state of Victoria. In just a few days, more than 45... (Journal of Geophysical Research - Atmospheres) [more]
Constraining the deep ocean circulation during glacial times (19 March 2011)
Scientists have known for 30 years that atmospheric carbon dioxide (CO2) levels varied substantially during the ice ages, yet the cause remains uncertain. Given that the deep ocean contains 50 times more carbon than the atmosphere, variable air-sea ... (Paleoceanography) [more]
Glacial dust carries iron to the Gulf of Alaska (18 March 2011)
Iron is an essential nutrient for phytoplankton in the ocean. How does iron get to the ocean? In the Gulf of Alaska the sources of iron and the processes that transport iron to the ocean are not well quantified. Crusius et al. (2011) combined satellite, meteor... (Geophysical Research Letters) [more]
Model suggests path to ending the ongoing Haitian cholera epidemic (18 March 2011)
Since early November 2010 a deadly cholera epidemic has been spreading across the Caribbean nation of Haiti, killing thousands of people and infecting hundreds of thousands. While infection rates are being actively monitored, health organizations have been lef... (Geophysical Research Letters) [more]
Characterizing lightning emissions associated with terrestrial gamma ray flashes (16 March 2011)
Terrestrial gamma ray flashes (TGFs) are bursts of high-energy radiation released in Earth's atmosphere during thunderstorms and are believed to be associated with lightning. Progress has been made, but much remains to be learned about the properties of these ... (Journal of Geophysical Research - Space Physics) [more]
Interpreting 231Pa/230Th observations and changes in ocean circulation (16 March 2011)
Understanding past changes in ocean circulation is important, because the ocean transports heat and changes in ocean circulation can affect climate. To better understand past ocean circulation changes, some researchers have used the ratio of two isotopes, prot... (Paleoceanography) [more]
Did the Laki volcano eruption cause the cold winter of 1783–1784? (15 March 2011)
In June 1783 the Laki volcano in Iceland began to erupt, and continued erupting for months, causing a major environmental disaster. The eruption spewed out toxic sulfuric acid aerosols, which spread over northern latitudes and caused thousands of deaths. That ... (Geophysical Research Letters) [more]
New emissions scenarios say 2°C warming may be unavoidable (10 March 2011)
When it comes to modeling climate change, researchers rely on the specification of plausible emissions scenarios to explore how climate will change over the coming century. Using a standardized set of carbon dioxide and other greenhouse gas scenarios allows re... (Geophysical Research Letters) [more]
Zooming in on aquatic denitrification hot spots (10 March 2011)
Inorganic nitrogen is an important resource for marine and aquatic ecosystems, acting as a fertilizer for phytoplankton and aquatic plants. When nitrogen concentrations soar, algae blooms can occur. Subsequently, when the algae blooms die, their decomposition... (Journal of Geophysical Research - Biogeosciences) [more]
Analyzing the ability of peat to trap gas bubbles (9 March 2011)
Peatlands, thick deposits of partially decayed plant matter, are a globally important carbon store. Peat soils make up one third of the global soil carbon pool and provide one of the largest natural sources of methane to the atmosphere. Bubbles of methane, an ... (Journal of Geophysical Research - Biogeosciences) [more]
Mapping U.S. West Coast surface circulation (5 March 2011)
A network of high-frequency radar systems designed for mapping ocean surface currents now provides unprecedented detail of coastal ocean dynamics along the U.S. West Coast. The network has grown over the past decade from a few radars to what is now considered ... (Journal of Geophysical Research - Oceans) [more]
Reservoirs affect irrigation and river discharge to oceans (5 March 2011)
Humans have long altered the water cycle by damming rivers to create reservoirs to store water. To examine the effects of large reservoirs on the global water cycle and the availability of water for irrigation, Biemans et al. (2011) analyzed reservoir o... (Water Resources Research) [more]
Deep water properties influenced by mixing along continental slopes of the northern Atlantic (5 March 2011)
In the northern Atlantic Ocean, cold salty water from the Arctic Ocean sinks to form North Atlantic Deep Water, a current that hugs the bottom of the ocean as it travels south toward Antarctica. The formation of this water mass is vital to large-scale global o... (Journal of Geophysical Research - Oceans) [more]
Improved model reproduces the 2003 European heat wave (4 March 2011)
In August 2003, record-breaking temperatures raged across much of Europe. In France, maximum temperatures of 37°C (99°F) persisted for 9 days straight, the longest such stretch since 1873. In the end, 40,000 deaths (14,000 in France alone) were attribu... (Geophysical Research Letters) [more]
Antarctic and Greenland ice sheet melting accelerating (4 March 2011)
The Antarctic and Greenland ice sheets are melting at an accelerating pace, a new study shows. Rignot et al. (2011) present a record of the mass balance of these polar ice sheets using two methods. One method measures ice sheet mass using gravity data from the... (Geophysical Research Letters) [more]
Tree ring record chronicles major Mesoamerican droughts (3 March 2011)
A new tree ring record chronicles major Mesoamerican droughts in the past millennium that may have contributed to the decline of some pre-Hispanic civilizations. Although there is other evidence of droughts during the past millennium, the paleoclimate record h... (Geophysical Research Letters) [more]
Lost in a fog on Mars (25 February 2011)
A pair of cameras mounted on the back of the Phoenix Mars Lander were used to capture how laser light, emitted by the lander's light detection and ranging (lidar) system, was scattered by water ice in the red planet's thin atmosphere. Moores et al. (2011) used... (Geophysical Research Letters) [more]
Using rainfall estimates to predict malaria transmission (23 February 2011)
Malaria kills nearly a million people each year, mostly in rural Africa. The disease is spread by mosquitoes, which thrive in wet areas, so malaria transmission is closely linked to rainfall. Rainfall estimates could therefore be used to help predict potential... (Water Resources Research) [more]
Trees may enhance landslide hazards (23 February 2011)
The amount of water saturated in soil layers depends on many factors, such as weather, climate, local geology, slope steepness, vegetation cover, and vegetation type. In forests, vegetation plays a key role in regulating soil saturation; tree canopies intercep... (Water Resources Research) [more]
New analysis can better anticipate the likelihood of flood occurrence (23 February 2011)
To manage freshwater resources, communities need information on how likely the volume of flow for a river or stream will equal or exceed a certain value of interest. Such information, for example, helps engineers know how much water to release into dams' spill... (Water Resources Research) [more]
The rain that drowned Pakistan could have been predicted (22 February 2011)
In the middle of the week, during the heart of summer, at the onset of the 2010 monsoon season, the northern end of Pakistan was pounded by torrential rain. Some areas of the country were drowned in 300 mm (11.8 inches) of rain over 4 days, 10 times the season... (Geophysical Research Letters) [more]
Auroral emissions reach ground level (19 February 2011)
Earth's auroral electrons radiate some of their energy in radio waves. Theories of the mechanism for emission of this radiation, known as auroral kilometric radiation (AKR), suggest that this radiation propagates away from Earth and cannot be detected at groun... (Geophysical Research Letters) [more]
What can opals tell us about past climate? (18 February 2011)
New insight into the mechanisms that caused Earth's glacial periods to abruptly end could come from opal accumulations in sediment cores. Previous studies have shown that the most recent glacial period ended when the Southern Hemisphere westerly winds intensif... (Paleoceanography) [more]
Corals expanding poleward due to warming climate (17 February 2011)
Corals are important organisms for ecosystems and are sensitive indicators of the effects of climate warming. While corals are bleaching and dying in tropical areas due to climate warming, in temperate areas they are expanding their range poleward as water tem... (Geophysical Research Letters) [more]
Atmospheric aerosols and climate over East Asia (17 February 2011)
As the most heavily populated and fastest-developing region of the world, East Asia is a major source of anthropogenic aerosols, which can affect air quality and climate. In addition, the arid regions of its interior are a significant source of dust in the atm... (Journal of Geophysical Research - Atmospheres) [more]
First images of Earth's plasma sheet (16 February 2011)
New images from the Interstellar Boundary Explorer (IBEX) mission capture part of Earth's magnetosphere for the first time. The magnetosphere, the large magnetic bubble around Earth, is a source of space weather that can damage satellites. The new observations... (Journal of Geophysical Research - Space Physics) [more]
New method to assess coral reef health (15 February 2011)
Coral reefs around the world are becoming stressed due to rising temperatures, ocean acidification, overfishing, and other factors. Measuring community level rates of photosynthesis, respiration, and biogenic calcification is essential to assessing the health ... (Geophysical Research Letters) [more]
Sediment records suggest El Niño variability will continue in warmer world (11 February 2011)
There has been some debate as to whether global warming could lead to a permanent El Niño state rather than a periodically varying El Niño–Southern Oscillation (ENSO), which occurs now. It has also been suggested that ice-free Arctic summers co... (Geophysical Research Letters) [more]
Measuring oceanic uptake of anthropogenic carbon (8 February 2011)
As anthropogenic emissions of carbon dioxide increase, contributing to global climate change, it is important to understand how much carbon the ocean absorbs. Watanabe et al. (2011) present a time series of observations of the vertical distributions of ... (Journal of Geophysical Research - Oceans) [more]
Groundwater is being depleted rapidly in California's Central Valley (5 February 2011)
Groundwater is being depleted in California's Central Valley at a rapid rate, according to data from the Gravity Recovery and Climate Experiment (GRACE) satellite. Famiglietti et al. (2011) analyzed 78 months of GRACE data covering October 2003 to March 2010 t... (Geophysical Research Letters) [more]
New method could improve hurricane surge forecasting (5 February 2011)
In recent years, hurricanes in the Gulf of Mexico, including Katrina and Ike, caused some of the highest surges on record and significant flooding, highlighting the need for good surge forecasts that can be used for early warning and evacuation. However, curre... (Geophysical Research Letters) [more]
Why was Arctic sea ice extent low in summer 2010? (29 January 2011)
Arctic sea ice extent has been declining in recent years, although ice extent varies with changes in atmospheric circulation, especially the phase of the Arctic Oscillation. The negative phase of the Arctic Oscillation has generally favored survival of sea ice... (Geophysical Research Letters) [more]
Exploring storage stability for underground carbon sequestration (29 January 2011)
With the world turning on to concerns about global climate change, strategies are being weighed to combat rising atmospheric carbon dioxide levels. One proposed solution is geologic carbon sequestration—storing liquid carbon dioxide deep underground. But... (Geophysical Research Letters) [more]
Observing polar flares at Jupiter (28 January 2011)
Jupiter's aurora often emits dramatic flares of ultraviolet light lasting several tens of seconds. Bonfond et al. (2011) captured high-time-resolution image sequences of the flares using the Space Telescope Image Spectrograph on board the Hubble Space Telescop... (Geophysical Research Letters) [more]
Assessing phosphorus reduction efforts in the Everglades (27 January 2011)
There is too much phosphorus in northern regions of the Florida Everglades, a result of years of agricultural and urban runoff. To deal with this problem, very large constructed wetlands, known as Stormwater Treatment Areas (STAs), have been built to strip pho... (Water Resources Research) [more]
No tipping point for Arctic Ocean ice (26 January 2011)
Declines in the summer sea ice extent have led to concerns within the scientific community that the Arctic Ocean may be nearing a tipping point, beyond which the sea ice cap could not recover. In such a scenario, greenhouse gases in the atmosphere trap outgoin... (Geophysical Research Letters) [more]
Water vapor trends over Boulder, Colorado (26 January 2011)
Water vapor in the atmosphere is responsible for a significant portion of the greenhouse effect, and even small changes in the upper troposphere or lower stratosphere can have a large effect on climate. A new analysis of balloon-borne water vapor measurements ... (Journal of Geophysical Research - Atmospheres) [more]
Simulating ocean carbon storage during the Last Glacial Maximum (25 January 2011)
During the cold period of the Last Glacial Maximum, about 21,000 years ago, atmospheric carbon dioxide (CO2) concentration was about 190 parts per million, compared to 280 parts per million in the preindustrial era and about 385 parts per million to... (Geophysical Research Letters) [more]
Soil temperature trends in Canada (21 January 2011)
Global warming is increasingly becoming a concern for society. Most reported warming trends are based on measured increases in air temperatures. However, trends in soil temperatures, also an important indicator of climate change, are less often reported. Qi... (Journal of Geophysical Research - Atmospheres) [more]
Fjords help to melt calving fronts on tidal glaciers that drain the Greenland ice sheet (21 January 2011)
The Greenland ice sheet is connected to the ocean through outlet glaciers that are in direct contact with the ocean. As global temperatures increase, many of these glaciers—particularly on Greenland's west coast—are melting at rates higher than tho... (Journal of Geophysical Research - Oceans) [more]
The traveling rings of the North Brazil Current (20 January 2011)
The North Brazil Current (NBC) moves northward along the northeastern coast of Brazil. Drawing from the South Equatorial Current and the outflow of freshwater from the Amazon River, the NBC brings warm, nutrient-rich water north of the equator. Up near the coa... (Journal of Geophysical Research - Oceans) [more]
Comparing different land surface heat flux estimates (20 January 2011)
Land surface heat fluxes are an important component of Earth's energy and water cycle, and quantifying these fluxes can help scientists better understand climate change. These heat fluxes are affected by factors such as cloud cover, precipitation, surface radi... (Journal of Geophysical Research - Atmospheres) [more]
Climate commitment in an uncertain world (15 January 2011)
Even if humans immediately ceased all emission of carbon dioxide (CO2) and other greenhouse gases, the planet would continue to warm, mainly due to thermal inertia of the world's oceans. This "climate commitment" has been of interest recently for bo... (Geophysical Research Letters) [more]
Using satellite data to estimate the North Atlantic Ocean circulation (15 January 2011)
By redistributing heat and freshwater around the planet, ocean currents play a crucial role in regulating Earth's climate. Accurate knowledge of the subtle regional variations in Earth's gravity field is fundamental to the measurement of ocean currents, but th... (Geophysical Research Letters) [more]
Tectonic plates relocked after 2005 earthquake in northeastern Japan (14 January 2011)
In August 2005 a magnitude 7.2 earthquake shook northeastern Japan. The quake occurred on the boundary of the North American plate and the Pacific plate off Miyagi prefecture. Earthquakes with a magnitude of about 7.5 have been occurring in this area approxima... (Geophysical Research Letters) [more]
More accurate measurements of total solar irradiance (14 January 2011)
Radiation from the Sun is the dominant source of energy input to the Earth's climate system; even small variations in solar irradiance can produce noticeable climate changes on global and regional scales. Determining how much of the observed global change can ... (Geophysical Research Letters) [more]
Modeling the giant impact crater on asteroid 4 Vesta (8 January 2011)
The asteroid 4 Vesta is one of the largest rocky bodies in the asteroid belt, with a mean diameter of about 530 km. An enormous impact crater, with a diameter of about 460 km and a depth of about 13 km, covers almost half of the asteroid's southern hemisphere.... (Geophysical Research Letters) [more]
Spooky action at a distance, for earthquakes (31 December 2010)
On 27 February 2010 a magnitude 8.8 earthquake rocked millions of Chileans from their slumber, but the South American people weren't the only ones so affected. New research by Peng et al. (2010) suggests that the trembling off the Chilean coast could have trig... (Geophysical Research Letters) [more]
How would the climate respond to melting of the West Antarctic Ice Sheet? (31 December 2010)
The West Antarctic Ice Sheet (WAIS) could collapse in the future as the rising sea level and warming climate destabilize the sheet. Previous studies have shown that melting of the WAIS could contribute to several meters of global sea level rise over the next f... (Paleoceanography) [more]
Dual-dynamic approach improves soil water transport model (31 December 2010)
To perfectly simulate the flow of water through the ground, one would need to know the details of every pore, passage, and air pocket in the soil. To circumvent these daunting requirements, researchers simulate soil moisture transport as if the water were flow... (Water Resources Research) [more]
Determining the underlying pattern of Arctic snowfall (24 December 2010)
Across the Arctic terrain, more than a hundred bright orange markers dot the landscape, sticking up from the fallen snow. The fiberglass poles, standing 1.5 m high and spaced 100 m apart, allow Sturm and Wagner (2010) to track snow depth over their 1-km... (Water Resources Research) [more]
China's lakes changed dramatically in recent decades (23 December 2010)
Significant changes have taken place in the number and size of China's lakes over the past several decades. To create a comprehensive picture of these changes over all of China, Ma et al. (2010) combined data from a wide variety of sources, including satellite... (Geophysical Research Letters) [more]
Evidence for water ice near the Martian equator (22 December 2010)
When one looks for water on Mars, the most obvious targets are the ice-capped polar regions. However, Shean (2010) found what appears to be buried water ice or an ice-debris mix within 38 craters in the Sinus Sabaeus region near the Martian equator. While prev... (Geophysical Research Letters) [more]
New evidence could let supereruption off the hook (22 December 2010)
It's a case of forensic analysis on the grandest scale: the possible near-extinction of the entire human race at the hands of one volcanic supereruption. The Younger Toba Tuff (YTT) eruption 74,000 years ago was accused of blanketing the sky with sulfate aeros... (Geophysical Research Letters) [more]
Oscillation of the location of Saturn's auroral ovals (21 December 2010)
Using images from the Hubble Space Telescope, Nichols et al. (2010) observed oscillations in the locations of Saturn's northern and southern auroral ovals. Both auroral ovals' positions oscillate 1°–2° between dawn and dusk. While the south... (Geophysical Research Letters) [more]
What controls the shape of sediment channels in river deltas? (21 December 2010)
When turbulent, sediment-filled rivers empty into oceans and lakes, the channels often divide repeatedly to form triangular deltas. Some channels, however, travel long distances before bifurcating, creating elongated channels. Understanding how these patterns ... (Journal of Geophysical Research - Earth Surface) [more]
Three-dimensional ash cloud observations could help keep planes in the air (21 December 2010)
In the spring of 2010 the Icelandic volcano Eyjafjallajökull erupted, sending a towering column of ash floating above the North Atlantic Ocean. The ash cloud shut down air traffic over much of Europe, significantly affecting the European economy. Although... (Journal of Geophysical Research - Atmospheres) [more]
Reversal of north and south components of radio emissions from Saturn (17 December 2010)
Saturn is known to emit intense radio emissions at kilometer wavelengths from its auroral regions. Observations in recent years found that the Saturn kilometric radiation (SKR) emission from the northern auroral region has a clocklike modulation with a period ... (Geophysical Research Letters) [more]
Determining a relevant measure of hydrologic connectivity (17 December 2010)
One of the biggest challenges in hydrology is to determine how rainwater moves through a landscape and feeds river flows. Water can circulate in underground channels, flow across the surface, or slowly permeate soil; it can either end up stored in the soil or ... (Water Resources Research) [more]
The varying life expectancies of American reservoirs (14 December 2010)
Tasked with controlling floods, coping through droughts, generating electricity, maintaining the flow of drinking water, preserving species' habitats, and managing the local environment, the United States' large-scale freshwater management system is extremely ... (Water Resources Research) [more]
Rain modifies ocean-atmosphere carbon dioxide exchange (9 December 2010)
Exchanges of carbon dioxide (CO2) between the atmosphere and the oceans play an important role in the global carbon cycle and in determining how much CO2 is stored in the atmosphere and how much is stored in the ocean. A new study shows t... (Geophysical Research Letters) [more]
Updated algorithms improve aerosol detection accuracy (7 December 2010)
The direct and indirect effects of airborne particles remain among the largest sources of uncertainty in scientists' understanding of climate change. NASA's Multiangle Imaging Spectroradiometer (MISR) has nine cameras that image Earth over a range of viewi... (Journal of Geophysical Research - Atmospheres) [more]
Extraordinary uplift of Yellowstone caldera (3 December 2010)
Beginning in 2004, the Yellowstone caldera, extending 40 km by 60 km in Yellowstone National Park, northwestern Wyoming, began a period of accelerated uplift, with rates of uplift as high as 7 cm/yr. From 2006 to 2009 the uplift rate slowed. Global Positioning... (Geophysical Research Letters) [more]
River-to-lake connectivity and habitat diversity in Mackenzie River delta, Canada (2 December 2010)
The 45,000 lakes in the Mackenzie River delta, Canada, represent an especially diverse aquatic habitat compared to lakes in surrounding Arctic areas. River-to-lake connectivity could play a role in this diversity, as river water entering lakes replenishes nutr... (Water Resources Research) [more]
Statistical model of rainfall could help improve urban drainage systems (2 December 2010)
Statistical models of rainfall activity can be useful for analyzing and improving urban drainage systems. Cowpertwait (2010) developed a statistical rainfall model in which storms originate randomly in space and time according to a Poisson process. Each... (Water Resources Research) [more]
Changing atmospheric chemistry with the swing of an axe (2 December 2010)
When a tree is cut down, carbon that has been stored for tens, hundreds, or even thousands of years is released to the environment. Similarly, felling that tree slightly alters the wind's path through the woods. If enough forest is cleared, significant changes... (Journal of Geophysical Research - Atmospheres) [more]
IRI model overestimated electron density in ionosphere during solar minimum (1 December 2010)
Electron density in the Earth's ionosphere, which affects satellites and communications, is highly variable. Solar activity, which increases and decreases on an approximately 11-year cycle, is a key driver of this ionospheric variability. The most recent s... (Geophysical Research Letters) [more]
What is the maximum sea level rise that coastal marshes can withstand? (1 December 2010)
As sea level rises, many coastal marshes worldwide are predicted to submerge. What is the maximum rate of sea level rise that a coastal marsh can survive? Many previous studies of this question have assumed that the coastal wetland landscape is static, but in ... (Geophysical Research Letters) [more]
Wave-particle interactions important in radiation belt dynamics (24 November 2010)
In the Earth's outer radiation belt the flux of energetic electrons and ions can vary significantly over short time periods in response to solar activity. These energetic particles can damage satellites, making it important to be able to understand and predict... (Geophysical Research Letters) [more]
Satellite data show inland water bodies warming (24 November 2010)
Many studies of global climate have used air temperature measurements to characterize recent warming trends. A new study shows that inland water bodies such as lakes and wetlands have also been warming steadily in recent decades. Schneider and Hook (2010) anal... (Geophysical Research Letters) [more]
Improving estimates of water volume in mountain snowfall (24 November 2010)
The spring snowmelt can sustain life, power hydroelectric energy generation, or be a source of devastating floods. A major issue for those trying to prepare for the melt season is that what is easiest to measure—the area of land covered in snow—doe... (Water Resources Research) [more]
Political bias in water quality monitoring (23 November 2010)
When legislators put out a call for scientific information, they expect the response to be based on the most stringent data possible. But when the information comes from a large monitoring network—like water quality measurements across Europe—the r... (Water Resources Research) [more]
Iron oxide observed in Earth's airglow (20 November 2010)
The Earth's night airglow, a weak emission of light caused by chemical reactions in the planet's atmosphere, has been studied for more than a century. Because iron is common in meteorites that deposit debris in Earth's atmosphere, it was expected that iron oxi... (Geophysical Research Letters) [more]
Ozone hole affects temperature and circulation in mesosphere (18 November 2010)
Observations have shown differences in altitude and brightness between polar mesospheric clouds (clouds made of ice crystals in the upper mesosphere) in the Northern Hemisphere and those in the Southern Hemisphere. Various mechanisms have been suggested to exp... (Geophysical Research Letters) [more]
Flood fatalities in Africa linked to settlement patterns (18 November 2010)
Flood-related fatalities in Africa have increased greatly over the past several decades. Has the intensity of flooding increased, perhaps owing to global climate changes? Or have human activity, population growth, and development patterns led to increased huma... (Geophysical Research Letters) [more]
Solar oxygen abundance measured (17 November 2010)
Oxygen is abundant in the Sun, yet the solar oxygen abundance has not been measured with high accuracy. von Steiger et al. (2010) used long-term solar wind data from the Ulysses spacecraft to measure the flux of oxygen ions, the flux of protons, and the ratio ... (Geophysical Research Letters) [more]
Massive release of methane from hydrates off New Zealand (10 November 2010)
Methane, a potent greenhouse gas, exists in large quantities in methane hydrates in sediments beneath the seafloor. In hydrates, methane molecules are trapped in cages of water molecules, but under some conditions these hydrates can become unstable and release... (Geophysical Research Letters) [more]
What controls bedrock channel geometry? (10 November 2010)
As rivers cut a path through bedrock, what influences the relationship between channel width, slope, and erosion rate? Data from naturally incising bedrock rivers show differing relationships among these parameters. For instance, while some studies show a stro... (Journal of Geophysical Research - Earth Surface) [more]
Hot spots of vegetation-climate feedbacks in Europe (10 November 2010)
Changing temperatures affect the growth of vegetation, which in turn can affect climate through changes in surface reflectivity, carbon dioxide (CO2) absorption, and evapotranspiration. These vegetation feedbacks to climate can be important, especia... (Journal of Geophysical Research - Atmospheres) [more]
Buoyancy explains asymmetry along mid-ocean ridges (10 November 2010)
Oceanic crust is formed at mid-ocean ridges, the seam-like boundaries between divergent tectonic plates that extend more than 50,000 km in length. This crust is made of solidified magma that has segregated from the upwelling, partially molten mantle below. Ge... (Geochemistry, Geophysics, Geosystems) [more]
Magnetic island observed at Earth's magnetopause (9 November 2010)
Understanding processes in the Earth's magnetosphere can help scientists understand and predict space weather and its effects on technology such as satellites and communications and navigation systems. Magnetic reconnection, in which magnetic field lines break... (Geophysical Research Letters) [more]
Southern Hemisphere Westerlies influence atmospheric carbon dioxide (4 November 2010)
The Southern Hemisphere Westerlies, the prevailing winds in the Southern Hemisphere, can strongly influence ocean circulation. D'Orgeville et al. (2010) used a climate model to study how changes in the Southern Hemisphere Westerlies affect atmospheric carb... (Geophysical Research Letters) [more]
New interpretation of atmospheric bromine during Arctic spring (3 November 2010)
Bromine, which destroys ozone, is emitted into the atmosphere during Arctic spring from inorganic sources including sea-salt aerosol, frost flowers, and cracks in sea ice. It had been believed that all areas of enhanced atmospheric bromine observed from space ... (Geophysical Research Letters) [more]
Split tectonic plate beneath western Japan could explain earthquake activity (3 November 2010)
Western Japan, a densely populated region, is prone to large earthquakes and volcanic eruptions, but the tectonics of the underlying region is not well understood. The shape of the Philippine Sea plate subducting beneath western Japan is a key factor in unders... (Geophysical Research Letters) [more]
Improving analysis of Earth's surface displacement (30 October 2010)
Advanced processing of spaceborne synthetic aperture radar (SAR) data allows improved measurements of Earth's surface deformation over time. The common base of these advanced methods is the differential interferometric SAR (DInSAR) technique, which exploits te... (Geophysical Research Letters) [more]
Model of Earth's gravity field developed from combined satellite data (28 October 2010)
Models of Earth's gravity field show how the planet's density varies in its interior and on its surface, depending on topography and geologic composition. For instance, dense mountains create an area of stronger gravitational pull. Pail et al. (2010) developed... (Geophysical Research Letters) [more]
A map of global groundwater depletion (26 October 2010)
Growing populations are increasing demand for water resources around the globe. In some regions where there is frequent water stress, groundwater is often used as a source of water in addition to surface water. When groundwater extraction consistently exceeds ... (Geophysical Research Letters) [more]
Meltwater within glaciers speeds ice sheet warming (23 October 2010)
Ice sheets and glaciers have been observed to respond rapidly to climate warming. Cryohydrologic warming, a new mechanism proposed by Phillips et al. (2010), could explain why. Meltwater can flow through networks of crevasses and fractures that develop or expa... (Geophysical Research Letters) [more]
Interpreting parameters in water transit time distribution (23 October 2010)
The distribution of the time it takes water or solute molecules to flow through a drainage basin, or catchment, can be useful for understanding variability, storage capacity, and pollutant transport in catchments and for comparing hydrology in different catchm... (Water Resources Research) [more]
Narwhals document continued warming of Baffin Bay (23 October 2010)
Baffin Bay, situated between northern Greenland and Canada, is a major gateway between waters from the North Atlantic and Arctic oceans. Dynamics within the bay help govern how much water from the Arctic flows south and sinks to form North Atlantic Deep Water,... (Journal of Geophysical Research - Oceans) [more]
Winter 2010 in Europe: A cold extreme in a warming climate (22 October 2010)
Abnormally cold weather and unusually large amounts of snow fell on Europe during the winter of 2009–2010. Cattiaux et al. (2010) analyzed records of temperature and atmospheric condition to show that although the 2010 winter in Europe was very cold and ... (Geophysical Research Letters) [more]
Toxic hydrocarbons measured in Gulf of Mexico (21 October 2010)
Oil contains compounds known as polycyclic aromatic hydrocarbons (PAH), which can be toxic. These compounds were released into the water during the Deepwater Horizon oil spill, which was larger than any previously studied release of oil. The impacts of the oil... (Geophysical Research Letters) [more]
Tracing the potential pathways of radioactive contaminants to surface waters (21 October 2010)
From the 1940s to the end of the Cold War, the U.S. Department of Energy maintained production facilities for manufacturing nuclear weapons along the Columbia River north of Richland, Washington. Known as the Hanford Site, the Rhode Island–sized area con... (Water Resources Research) [more]
Ozone-destroying iodine measured in Arctic atmosphere (19 October 2010)
Iodine in the atmosphere can destroy ozone and can also accelerate bromine-catalyzed ozone depletion. Iodine has been measured in the Antarctic atmosphere at levels that cause significant ozone depletion. Mahajan et al. (2010) now report detailed measur... (Journal of Geophysical Research - Atmospheres) [more]
Atmospheric dynamics could drive El Niño events (16 October 2010)
Scientists generally believe that ocean dynamics are the primary factor controlling El Niño sea surface temperature variability. However, new simulations show that atmospheric dynamics can account for many of the features of El Niño that were previou... (Geophysical Research Letters) [more]
Why has oil from the Exxon Valdez persisted so long on beaches? (16 October 2010)
The 1989 Exxon Valdez oil spill released more than 11 million gallons of oil into Prince William Sound, Alaska, polluting 800 km of beaches. In some areas the spilled oil has persisted on beaches more than 20 years later. To examine the factors affect... (Water Resources Research) [more]
Record warming in South Pacific associated with central Pacific El Niño (14 October 2010)
In 2009–2010, a record warming occurred in the South Pacific and western Antarctica. Lee et al. (2010) analyzed satellite and in situ observations to document the oceanic and atmospheric conditions associated with the sea surface temperature anomalies. T... (Geophysical Research Letters) [more]
New model shows how tiny features influence large-scale flow through an aquifer (13 October 2010)
Modeling large-scale effects from small-scale influences is a delicate act. Even when researchers know small changes can make a big difference, for example, for the diffusion of a solute through an aquifer, attempts to predict the outcome can be hindered by th... (Water Resources Research) [more]
Gravity measurements show sources of sea level change (12 October 2010)
Sea level is rising as ice on continents melts and adds to the volume of the ocean. The Gravity Recovery and Climate Experiment (GRACE) satellites measure changes in Earth's gravity field, which makes it possible to observe patterns of mass exchange betwee... (Geophysical Research Letters) [more]
New method for assessing uncertainty in groundwater models (12 October 2010)
Groundwater models used to predict flow and transport through aquifers often have many parameters and take a significant amount of computational time. Because of this, it has been challenging to assess the uncertainty in these models. Keating et al. (20... (Water Resources Research) [more]
Two eyes are better than one for measuring rain from space (12 October 2010)
One predicted consequence of climate change is a global redistribution of precipitation and the resultant shifts in regional rainfall volumes. To forecast the details of Earth's changing climate, researchers rely on the accurate detection and measurement of ra... (Journal of Geophysical Research - Atmospheres) [more]
New method to estimate daily flow rates at streams that lack gages (9 October 2010)
Records of daily streamflow rates can help scientists estimate future runoff volumes or determine whether fish and other aquatic species have enough water to survive an upcoming season. Many streams are monitored by gages; however, the sheer number of catchmen... (Water Resources Research) [more]
Large errors in hydrological models can arise from computational techniques (8 October 2010)
Hydrological models are frequently used in flood forecasting, water resources assessments, and other environmental management projects. They are also useful tools for advancing scientific understanding of hydrological processes. In many applications to date, e... (Water Resources Research) [more]
Sediment transport confuses landscape record of environmental change (6 October 2010)
Over time, landscapes change in response to climate change, tectonic motion, and sea level changes. It is generally believed that these environmental changes are recorded in landscape patterns that scientists can use to interpret past changes. However, sedimen... (Geophysical Research Letters) [more]
Electrons in plasma sheet absorbed by lunar surface (1 October 2010)
For a few days around the time of each full Moon, the Moon passes through Earth's plasma sheet, the plasma-filled region separating the two lobes of Earth's magnetotail. In this region, plasma conditions are different from plasma conditions the Moon encounters... (Geophysical Research Letters) [more]
Laboratory experiments help to better define stream erosion and deposition (1 October 2010)
Streams and rivers, through eroding banks and depositing sediment, are primary agents of change to Earth's landscapes. At a fundamental level, such erosion and deposition are dependent on bed load transport—the motion of particles rolling, sliding, or tr... (Journal of Geophysical Research - Earth Surface) [more]
Has the ozone hole caused Antarctic sea ice extent to increase? (29 September 2010)
While sea ice extent has declined dramatically in the Arctic in recent years, it has increased slightly in the Antarctic. Some scientists have suggested that increased Antarctic sea ice extent can be explained by the ozone hole over Antarctica. Previous simula... (Geophysical Research Letters) [more]
Tropical cyclone size distribution characterized (29 September 2010)
A new climatology of tropical cyclone size was created by Chavas and Emanuel (2010) using near-surface wind measurements made during 1999–2008 using the QuikSCAT satellite microwave scatterometer. Their study showed that cyclone size follows an approxima... (Geophysical Research Letters) [more]
Sandbar migration difficult to predict (29 September 2010)
Nearshore sandbars migrate out toward the ocean and then can move back due to the interaction of sand and waves. Pape et al. (2010) studied several data-driven neural network models and a physically detailed model of sandbar migration to see how well t... (Journal of Geophysical Research - Earth Surface) [more]
Assessing regional impacts of geoengineering (28 September 2010)
As the climate warms along with rising levels of atmospheric carbon dioxide (CO2), geoengineering has been suggested as an emergency option to cool the planet. One possibility is implementing a solar radiation management project, such as injecting s... (Geophysical Research Letters) [more]
Separating pollution from sea spray helps to better represent how aerosols affect clouds (28 September 2010)
Aerosols suspended in the atmosphere over the ocean can typically be classified into two categories: particles from sea spray and particles from continents, the latter of which includes soot and other pollutants from anthropogenic emissions. Combined, these ae... (Journal of Geophysical Research - Atmospheres) [more]
Sulfate isotopes explain past atmospheric conditions in Antarctica (28 September 2010)
The past 230 years have seen great changes in atmospheric conditions in the Northern Hemisphere, due to pollutants released from biomass and coal burning as societies became industrialized and the fossil fuel burning that began to dominate energy consumption a... (Journal of Geophysical Research - Atmospheres) [more]
Strong connections observed between climate patterns of the stratosphere and troposphere (25 September 2010)
Roughly every 28 months, the zonal winds in the stratosphere at the equator cycle from easterly to westerly and then back to easterly. Known to atmospheric scientists as the quasi-biennial oscillation (QBO), these shifting wind patterns result when the energy ... (Journal of Geophysical Research - Atmospheres) [more]
Simulations show deep oil from leak is confined to Gulf of Mexico (23 September 2010)
The Deepwater Horizon oil leak was one of the largest environmental disasters in recent history, and aspects of its environmental impact are still unknown. In addition to surface oil slicks, large underwater plumes of oil were found. To help evaluate the poten... (Geophysical Research Letters) [more]
Understanding the eruption of the Soufrière Hills volcano (23 September 2010)
When the Soufrière Hills volcano erupted in 1995, it wreaked havoc on the Caribbean island of Montserrat. Many scientists have since studied the eruption, but the internal structure of the volcano had not been well characterized until recently. Voight and... (Geophysical Research Letters) [more]
Mapping moisture recycling and global water resources (22 September 2010)
Water that falls as precipitation in one region may have originated in a distant region, or it may be recycled moisture that originated as evaporation within the region. Global wind patterns, topography, and land cover all play a role in moisture recycling pat... (Water Resources Research) [more]
High-resolution measurements of lunar topography (18 September 2010)
Selection of landing sites for potential human or robotic lunar missions requires precise knowledge of lunar topography. Contributing to that knowledge, Smith et al. (2010) present initial observations from the Lunar Orbiter Laser Altimeter (LOLA) on board the... (Geophysical Research Letters) [more]
Ocean color affects tropical cyclone formation (17 September 2010)
The color of the ocean can alter the frequency of tropical cyclones, according to a new study. The absorption of sunlight is affected by the concentration of chlorophyll, with the Sun's heat penetrating deeper in clear, low-chlorophyll waters. In the ocean gyr... (Geophysical Research Letters) [more]
Modeling ionospheric variations (14 September 2010)
Plasma density irregularities in the ionosphere are important to understand and predict because they can cause radio scintillation that affects communications and navigation systems. During an ionospheric phenomenon known as equatorial spread F (ESF), l... (Geophysical Research Letters) [more]
Magma chamber imaged under Lake Toba (11 September 2010)
The Toba caldera in northern Sumatra, Indonesia, was formed about 75,000 years ago by an enormous explosive volcanic eruption that had significant effect on global climate. To learn more about its underlying crustal structure, Stankiewicz et al. (2010) created... (Geophysical Research Letters) [more]
Coriolis forces affect flow in submarine channels (11 September 2010)
Coriolis forces due to the Earth's rotation deflect winds and ocean flows to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. In sinuous submarine channels, Coriolis forces can drive secondary circulation of turbidity currents a... (Geophysical Research Letters) [more]
Limiting global warming may not limit heat wave risk (4 September 2010)
Recent policy discussions on climate change have focused on limiting global average temperature increases. For instance, the European Union has set a goal of limiting global warming to 2°C. However, this goal represents a global average—regional and... (Geophysical Research Letters) [more]
Why are ice cloud products from the two most popular remote sensing methods so different? (3 September 2010)
High-altitude ice clouds play a critical role in Earth's climate system, serving to both limit the penetration of incoming solar radiation to the surface and inhibit infrared radiation from escaping to space. Satellite-based, long-term, global ice cloud remote... (Journal of Geophysical Research - Atmospheres) [more]
No lightning detected on Mars during 5-year search (1 September 2010)
It has been suggested that dust storms on Mars might generate electric fields large enough to produce lightning-like electrical discharges, and a recent study reported evidence of such lightning. If lightning does occur on Mars, it could present a hazard for s... (Geophysical Research Letters) [more]
Teasing out how aerosol levels influence precipitation (1 September 2010)
Aerosol particles such as dust, smog, smoke, and oceanic haze play an important role in the physics of cloud generation—with all other factors fixed, an increase in aerosol concentrations results in more numerous but smaller water droplets within clouds.... (Journal of Geophysical Research - Atmospheres) [more]
Estimating forest rainfall interception from satellite observations (31 August 2010)
Although most rainfall over continents reaches the ground, a significant portion is caught by the forest canopy and evaporates directly. To better understand feedbacks between evaporation and climate, and to estimate the effects of climate change and deforesta... (Journal of Geophysical Research - Atmospheres) [more]
Low solar activity explains contracted thermosphere (25 August 2010)
From 2007 to 2009, the outermost layer of the atmosphere, the thermosphere, was abnormally cool and contracted, with lower than normal densities at altitudes near 400 km. In fact, the thermosphere's density, determined by measuring the drag on satellites, was ... (Geophysical Research Letters) [more]
Why do clouds prevent heat from escaping Earth in a warming climate? (25 August 2010)
Clouds affect Earth's surface temperature in two key ways: They exert a cooling influence on the planet by reflecting solar (shortwave) radiation back to space and a warming influence on the planet by reducing the amount of infrared (longwave) radiation emitte... (Journal of Geophysical Research - Atmospheres) [more]
Oxygen and hydrogen escape differently from Venus's atmosphere (21 August 2010)
In the upper atmosphere of Venus, ions are exposed to magnetic and electric fields created by the solar wind. These electric and magnetic fields enable oxygen and hydrogen ions, the components of water, to escape from the atmosphere. Previous studies have main... (Geophysical Research Letters) [more]
Measuring the rate of mountain building in New Zealand (21 August 2010)
For the past 20 million years, the Southern Alps Mountains, on the South Island of New Zealand, have been growing as continental plates converge. Beavan et al. (2010) used 10 years of Global Positioning System data to measure the present-day rates of vertical ... (Geophysical Research Letters) [more]
How do compliant fault zones respond to nearby earthquakes? (20 August 2010)
Compliant fault zones are weaker than surrounding rocks and are more responsive to small stress changes caused by nearby earthquakes. Duan (2010) modeled how compliant fault zones around existing faults respond to nearby earthquakes. He found that some portion... (Geophysical Research Letters) [more]
Widespread Amazon tree death caused by single storm event (19 August 2010)
Extreme precipitation events are likely to occur more often in Amazonia and elsewhere as the world's climate changes. Storms are known to damage trees, but no systematic study has been done of tree loss during storms in tropical forests. To quantify tree morta... (Geophysical Research Letters) [more]
Landmass geometry constrains Arctic sea ice extent (19 August 2010)
Arctic sea ice has retreated significantly in recent years, reaching a record low in September 2007. It is known that the seasonal cycle in Arctic sea ice extent is not symmetric—seasonal ice retreat proceeds gradually during early summer and then accel... (Geophysical Research Letters) [more]
Complexities of aquifer systems complicate reaction rate estimates (13 August 2010)
Contaminant concentrations in aquifers can change as chemical reactions occur during groundwater transport through the aquifer. For instance, denitrification, in which the contaminant nitrate (NO3-) is converted to molecular nitrogen (N2), reduces N... (Water Resources Research) [more]
Characterizing channels for transport of melt in mantle (13 August 2010)
Rock in the Earth's mantle, for example, beneath mid-ocean ridge spreading centers, melts as it upwells toward the surface. This buoyant melt rises through the mantle to the surface, where it solidifies and becomes part of the Earth's crust. However, the pathw... (Geophysical Research Letters) [more]
Southward interplanetary magnetic field causes structuring in the polar cap ionosphere (13 August 2010)
Electron density variations in the ionosphere are important for understanding space weather, as they affect the Global Positioning System and radio communications. Bahcivan et al. (2010) used some of the first measurements from the U.S. National Science Founda... (Geophysical Research Letters) [more]
Iceberg release changed after Columbia Glacier became ungrounded (7 August 2010)
In 2007, the terminus of Columbia Glacier, a tidewater glacier in Alaska, suddenly became ungrounded and began floating. Columbia is now the only known floating Alaskan tidewater glacier. A new study analyzed the glacier's changing calving (iceberg release) be... (Geophysical Research Letters) [more]
Global warming began with early hunters (7 August 2010)
According to a new study, early hunters 15,000 years ago in Siberia and Beringia contributed to global warming even before the emergence of agriculture. Sometime after the ice age, the mammoth population began to die down due to climate change and hunting. Acc... (Geophysical Research Letters) [more]
How does emissions mitigation policy affect ocean acidification? (7 August 2010)
The anthropogenic release of carbon dioxide (CO2) has increased significantly in recent years. Some of this CO2 is absorbed by the ocean, increasing its acidity (lowering its pH). Studies have shown that since 1750 the absorption of CO
Summer heat waves to be a routine occurrence (6 August 2010)
This year has been the hottest on record globally, with many areas around the world experiencing extremely hot conditions this summer. According to Diffenbaugh and Ashfaq (2010), extreme heat waves can be expected to be a more common occurrence over the next 3... (Geophysical Research Letters) [more]
New map shows height of global forest canopy (5 August 2010)
Scientists have developed a map that details the heights of the world's forests. It is the first map that spans the entire world based on a single model. The map was generated from lidar (light detection and ranging) data collected over a 7-year period from NA... (Geophysical Research Letters) [more]
Dry lake bed salts promote cloud formation (3 August 2010)
One of the major uncertainties in climate modeling is the effect of aerosol particles on cloud formation. Sea salt in the air has been known to be important in cloud formation over oceans. Now a new study provides the first direct measurements of clouds showin... (Journal of Geophysical Research - Atmospheres) [more]
Extensive relict coral reef found in southern Pacific (3 August 2010)
Coral reefs are sensitive to climate change and track sea level. New observations show that an extensive coral reef existed in the southern Pacific Ocean thousands of years ago. Woodroffe et al. (2010) used multibeam sonar, coring, and dating to examine a rel... (Geophysical Research Letters) [more]
Changes in Sun's plasma conveyor belt affect solar cycle (30 July 2010)
The Sun goes through cycles lasting approximately 11 years that include phases with increased magnetic activity, more sunspots, and more solar flares, and phases with less activity. The level of activity on the Sun can affect navigation and communications syst... (Geophysical Research Letters) [more]
What are the effects of controlling fossil fuel soot? (29 July 2010)
Fossil fuel soot, emitted during diesel fuel, jet fuel, and coal combustion, and biofuel soot, emitted mainly through burning of wood and organic waste for heating and cooking, can affect climate and air quality. How much does each of these contribute to globa... (Journal of Geophysical Research - Atmospheres) [more]
Shift of ozone hole exposed South America to increased ultraviolet light (27 July 2010)
The ozone layer, which protects humans, plants, and animals from potentially damaging ultraviolet (UV) light from the Sun, develops a hole above Antarctica in September that typically lasts until early December. However, in November 2009, that hole shifted its... (Geophysical Research Letters) [more]
El Niño intensity increasing in the central equatorial Pacific (24 July 2010)
El Niño is the dominant year-to-year climate fluctuation on the planet, influencing patterns of weather variability worldwide. Recently, a new type of El Niño has been documented, the so-called "central Pacific" El Niño. These El Niños exhi... (Geophysical Research Letters) [more]
Convergence of El Niño and North Atlantic Oscillation brings heavy snowfall (24 July 2010)
The winter of 2009–2010 had anomalously large snowfall in central parts of the United States, particularly the mid-Atlantic states, and in northwestern Europe. The weather encouraged deniers of global warming to deride climate change science. To help bet... (Geophysical Research Letters) [more]
Understanding slab-plume interaction beneath the Pacific Northwest (22 July 2010)
During the past 65 million years, the Pacific Northwest has experienced significant tectonic and volcanic activity, including volcanism in the Yellowstone region. The origins of volcanism in the area have been debated. To learn more about the region's tectonic... (Geophysical Research Letters) [more]
New study casts doubt on evidence for Younger Dryas impact theory (20 July 2010)
A new study challenges a previous hypothesis that a comet explosion or impact about 12,900 years ago caused devastating fires over much of Northern America and Europe and triggered an abrupt global cold period known as the Younger Dryas. Proponents of the impa... (Geophysical Research Letters) [more]
Large atmospheric study investigates tropical tropopause layer (15 July 2010)
The tropical tropopause transition layer (TTL), starting at about 12 km in altitude, is a transition layer between the tropical troposphere (the layer nearest Earth) and the stratosphere above. The TTL can influence the chemistry of the stratosphere, including... (Journal of Geophysical Research - Atmospheres) [more]
Measuring the Eyjafjallajökull volcanic ash plume over central Europe (15 July 2010)
The 14 April eruption of Icelandic volcano Eyjafjallajökull sent enormous plumes of thick ash over Europe, disrupting air travel for days. Ansmann et al. (2010) report lidar (light detection and ranging) and photometer observations of the ash plume over c... (Geophysical Research Letters) [more]
Melting floating ice causing sea levels to rise (13 July 2010)
In recent years, the volume of ice floating in the world's oceans has changed significantly. Some believe that these changes do not affect the sea level, and floating ice loss has often been neglected in studies of sea level rise. However, because ice is fresh... (Geophysical Research Letters) [more]
New observations of blue sprite spectra (13 July 2010)
Sprite lightning, a striking and unusual type of lightning that occurs in the upper atmosphere above thunderclouds, consists of a main portion, which is usually red, and thin tendril-like streamers that emanate from the main portion. The streamers have a strea... (Geophysical Research Letters) [more]
A case study of satellite monitoring of ammonia (10 July 2010)
Emissions of ammonia (NH3), which come mainly from agriculture, have increased in recent decades and are likely to continue to rise as the world's population grows and demand for food increases. Ammonia pollutes the air, increases creation of partic... (Journal of Geophysical Research - Atmospheres) [more]
Globalization of water can increase vulnerability to droughts (10 July 2010)
Water is vital for human life. It is used for not only drinking but also producing electricity, washing, cooking, and growing food. Lately there has been a disproportionate population growth in arid regions, and the demand for water in those regions exceeds th... (Geophysical Research Letters) [more]
Peatlands play important role in global carbon cycle (9 July 2010)
Peatlands, lands in which soil has accumulated large amounts of decaying plant matter, play an important role in the global carbon cycle because they contain significant stores of carbon and can release that carbon into the atmosphere. Although previous studie... (Geophysical Research Letters) [more]
Studying heat transport in geological environments using a random walk model (8 July 2010)
Environmental and industrial applications such as oil drilling, geothermal engineering, and radioactive waste storage rely on knowledge of heat transport through geological environments. It is often assumed that heat transfer is governed by a simple equation k... (Water Resources Research) [more]
Identifying oceanic sources of continental precipitation (7 July 2010)
Ninety percent of water evaporated from the oceans precipitates back to the oceans. The remaining 10% is transported to the continents and plays an important role in the land branch of the hydrological cycle. Studies have suggested that rising global temperatu... (Geophysical Research Letters) [more]
Studying the Sun's effects on Earth's atmosphere (2 July 2010)
The Sun contributes to climate and weather on Earth through its influence on the atmosphere, and even small variations in solar radiation can affect Earth. The Sun-Earth couplings and interactions can be complex, and natural variability can make it difficult t... (Journal of Geophysical Research - Atmospheres) [more]
A less invasive method to measure groundwater permeability (1 July 2010)
Hydraulic conductivity quantifies how easily water moves through aquifers, a factor important for management of water resources, the design of wells, and remediation of contaminated sites. It typically shows strong spatial fluctuations, so determining hydrauli... (Water Resources Research) [more]
Trend discrepancies found in tropical cyclone data sets (30 June 2010)
It has been hotly debated recently whether global warming has led to an increase in tropical cyclone activity in the western North Pacific over the past several decades. One complicating factor in the debate is that different data sets show different trends in... (Journal of Geophysical Research - Atmospheres) [more]
Does the ocean influence the atmosphere's response to ozone? (29 June 2010)
Southern Hemisphere weather patterns have changed significantly over the past few decades. Modeling studies have shown that these changes can be mainly attributed to stratospheric ozone depletion. However, the ozone layer is predicted to slowly recover over th... (Geophysical Research Letters) [more]
Intertwined feedback loops between atmospheric chemistry and climate (26 June 2010)
Accurately predicting climate change involves a thorough knowledge of how perturbations in the Earth's radiation balance feed back to influence temperature and other climate variables. These feedbacks alter the Earth's capability to absorb incoming solar radia... (Journal of Geophysical Research - Atmospheres) [more]
Changes to hydrological cycle continue after carbon dioxide is reduced (23 June 2010)
One of the most significant direct effects of global warming is an alteration of the hydrological cycle affecting the world's water supplies, floods, and droughts. Most studies assume that if human-induced temperature changes were reversed, the hydrological cy... (Geophysical Research Letters) [more]
Map of lunar hydrogen points to large amounts of water ice (22 June 2010)
In October 2009, NASA's LCROSS mission smashed into a crater on the Moon and clearly detected water there, confirming other studies that suggested that water ice existed on the Moon. Scientists can learn more about lunar water by studying the abundance and dis... (Geophysical Research Letters) [more]
Why is the Density of the Thermosphere Abnormally Low? (19 June 2010)
The total mass density of the upper thermosphere (~200 to 600 kilometers in altitude) was lower during the 2008 solar minimum than at any other time during the space age. Using historical records of thermospheric density, Emmert et al. (2010) compared the beha... (Geophysical Research Letters) [more]
Kelvin-Helmholtz waves observed in flyby of Mercury (18 June 2010)
Kelvin-Helmholtz waves, the surface waves that form when two fluids with different speeds move past each other, can be created along the magnetopause when solar wind plasma interacts with a planet's magnetosphere. These waves have previously been observed in E... (Geophysical Research Letters) [more]
Underground clues to past atmospheric heat content (18 June 2010)
Before a global climate model can be used by scientists to predict future climate patterns, it must first successfully predict the climate of the past as known by historical records or as inferred by proxy data (for example, oxygen isotopes in ice cores and tr... (Journal of Geophysical Research - Atmospheres) [more]
The coastal fate of terrestrial soil organic carbon (11 June 2010)
Soil found in the Arctic stores half of the world's soil organic carbon (SOC) and twice as much carbon as is in the atmosphere. Rising temperatures in the Arctic are thawing the permafrost; some of the soil carbon then degrades into greenhouse gases that are r... (Geophysical Research Letters) [more]
Is there a relationship between aerosol and cloud properties? (2 June 2010)
The interaction of aerosol and clouds is one significant uncertainty in studies of anthropogenic forcing of climate. To learn more about the effects of fine aerosols on cloud microphysics, Constantino and Bréon (2010) performed a multisensor analysis of the at... (Geophysical Research Letters) [more]
Direct access to subglacial Lake Ellsworth (2 June 2010)
Since the discovery in 1996 that Lake Vostok, a subglacial (hidden under a glacier) lake in Antarctica, possessed a water column of more than 500 m, scientists have come to believe that subglacial lakes are feasible habitats for life and may contain records of... (Geophysical Research Letters) [more]
Nonuniform data created spurious trend in sunshine hours (29 May 2010)
With climate change an increasingly important scientific and political issue, it is essential to have an accurate picture of the causes of regional climate changes. In most cases, warming has been related to a combination of anthropogenic and natural factors. ... (Geophysical Research Letters) [more]
Realistic models of aquifer conduits (29 May 2010)
The spatial distribution of underground rock units and geologic structures governs the flow of groundwater and thus any pollutant plumes within this groundwater. Such information is critical to water resources managers and to those drilling for oil and natural... (Water Resources Research) [more]
Correcting model imperfections (27 May 2010)
By their nature, environmental models are unable to perfectly simulate natural phenomena. Misfits between model predictions and field measurements are often characterized by the term "structural noise." The presence of this noise can adversely affect the estim... (Water Resources Research) [more]
Can California's water supply infrastructure handle severe prolonged drought? (21 May 2010)
Recent studies show that prolonged episodes of extreme drought have occurred in the past and may be more likely under human-induced greenhouse warming. This is of particular concern to communities in California, which combined serve as the agricultural center ... (Water Resources Research) [more]
Uranium mapped on Moon (20 May 2010)
Studies of abundances and distribution of radioactive elements can help answer questions about the formation and evolution of the Moon. Using data from instruments on board the Japanese Kaguya spacecraft (also known as SELENE), Yamashita et al. (2010) mapped t... (Geophysical Research Letters) [more]
New samples taken along Pacific Antarctic Ridge (19 May 2010)
Understanding the geochemistry along ocean ridges can help scientists understand the dynamics and evolution of the mantle. To complete sampling of the Pacific Antarctic Ridge, Hamelin et al. (2010) collected data on major elements, trace elements, and strontiu... (Geophysical Research Letters) [more]
Stratospheric influence on the ionosphere could improve ionospheric forecasts (18 May 2010)
Variations in the ionosphere, the charged upper portion of Earth's atmosphere (about 100–1000 km in altitude), can affect radio communications and navigation systems. Solar activity is known to strongly influence the ionosphere; recently, scientists have... (Geophysical Research Letters) [more]
Understanding the magma distribution in the Taupo Volcanic Zone (18 May 2010)
The Taupo Volcanic Zone, on the North Island of New Zealand, is an active region of intense volcanism with high heat flow. The high heat flux from this zone is comparable to that found in Iceland and at Yellowstone. It has been suggested that large volumes of ... (Geophysical Research Letters) [more]
Visible lightning imaged on Saturn (15 May 2010)
Lightning, common on Earth, has also been detected on Jupiter, and previous studies have reported indirect evidence for lightning on Saturn. Visible lightning has now been imaged on Saturn for the first time. Dyudina et al. (2010) report that on 17 August 2009... (Geophysical Research Letters) [more]
Airborne study reveals Arctic sea ice thickness (14 May 2010)
Arctic sea ice extent has declined over the past several decades and in 2007 reached a record-breaking low. Since then, ice has begun to recover. Sea ice thinning is expected to continue with climate change, although there is significant natural variability in... (Geophysical Research Letters) [more]
Is the weekend effect anthropogenic or natural? (14 May 2010)
It has been suggested that human activity causes a "weekend effect" in which meteorological variables show weekly cycles. For instance, researchers have observed that the difference between daily maximum and minimum temperatures (diurnal temperature range) inc... (Geophysical Research Letters) [more]
Inappropriate data filtering skewed a recent study (14 May 2010)
About every 4 years, faltering easterly trade winds over the tropical Pacific Ocean cause warm waters to linger, generating an anomalously warm wet period in the eastern Pacific for about 6 months. During these times the western Pacific becomes cooler and drie... (Journal of Geophysical Research - Atmospheres) [more]
Climate change and urbanization increase urban heat island effect (8 May 2010)
The urban heat island effect, in which an urban area is notably warmer than surrounding nonurbanized areas, will likely increase in coming decades, as urbanization is projected to increase dramatically, reaching 6 billion urban dwellers worldwide by 2050. Howe... (Geophysical Research Letters) [more]
Ozone recovery and climate change will affect the atmosphere near Earth's surface (6 May 2010)
Although ozone in the stratosphere (~10–50 km in altitude) helps protect life on Earth from harmful solar ultraviolet radiation, at the lower altitudes in the troposphere, close to Earth's surface, ozone is a major constituent of smog and has detrimental... (Geophysical Research Letters) [more]
A narrow midmantle plume below southern Africa (4 May 2010)
Mantle plumes, columns of very hot material in Earth's mantle, drive volcanic activity and transfer heat from Earth's core to the upper mantle. A new midmantle plume has now been detected below southern Africa. Sun et al. (2010) analyzed data from multiple eve... (Geophysical Research Letters) [more]
Satellites monitor air pollutant emissions in China (29 April 2010)
A new satellite study verifies that Chinese emission control efforts did reduce power plant emissions of sulfur dioxide (SO2,), a harmful gas that causes acid rain and can form sulfate aerosols, which play an important role in the climate system by ... (Geophysical Research Letters) [more]
Predicting how a central Pacific El Niño will evolve (29 April 2010)
El Niños, in which warmer than usual sea surface temperatures occur in the equatorial Pacific Ocean, are known to have a major influence on weather patterns worldwide. Yu and Kim (2010) categorized the ways in which certain types of El Niño events evolve. They... (Geophysical Research Letters) [more]
What factors influence drainage patterns? (24 April 2010)
Drainage density, a measure of how much the landscape is dissected by channels, is known to vary among different climates. The prevailing thought holds that drainage density is low in arid regions because of low runoff; it increases in semiarid regions as runo... (Water Resources Research) [more]
Simple description of atmospheric organic aerosol (22 April 2010)
Atmospheric organic aerosol consists of a variety of organic molecules that are either directly emitted into the atmosphere or form through chemical reactions in the atmosphere. Organic aerosol can affect climate by altering the amount of sunlight that is refl... (Geophysical Research Letters) [more]
Demonstrating the equivalence of two atmospheric velocity statistics (17 April 2010)
Atmospheric velocity (wind speed) statistics are a key part of weather prediction as well as climate studies. Velocity statistics, which are used in describing atmospheric dynamics as a function of spatial scale, season, or geographic region, are usually calcu... (Geophysical Research Letters) [more]
Sunlight reflection confirms liquid lake on Titan (7 April 2010)
A glint of sunlight reflecting from the surface of Saturn's moon Titan indicates the presence of a lake filled with liquid. Earlier observations showed features that look like terrestrial lakes and seas in Titan's northern polar region, but the presence of liq... (Geophysical Research Letters) [more]
Rivers rebound as woodland replaces degraded grassland (3 April 2010)
The surprising results of a new study suggest that contrary to previous belief, streamflow can increase when grassland converts to woodland. Wilcox and Huang (2010) studied trends in the base flow (water supplied by groundwater and springs) and stormflow (wate... (Geophysical Research Letters) [more]
Stratigraphic column could provide insight into Mars's climate history (2 April 2010)
A new stratigraphic record of Martian polar layered deposits could help scientists shed light on Mars's climate history. Stratigraphic layers can give scientists important clues about the conditions at the time the layer of rock formed. Fishbaugh et al. (2010)... (Geophysical Research Letters) [more]
Thick water ice observed in lunar craters (31 March 2010)
Water ice exists in large quantities in many small craters near the Moon's north pole, according to a new study. Spudis et al. (2010) present initial results from the miniature synthetic aperture radar (Mini-SAR) experiment on board the Indian Chandrayaan 1 sp... (Geophysical Research Letters) [more]
Model explains features of sprites (30 March 2010)
A sprite is an electrical discharge similar to lightning, but it occurs in the upper atmosphere (50–90 km in altitude), above large thunderstorms. These large flashes of light, which are triggered in almost all cases by positive lightning discharge betwe... (Geophysical Research Letters) [more]
Gullies on Mars indicate presence of liquid water (26 March 2010)
Present-day gully activity on Mars provides new evidence for transient liquid water. Reiss et al. (2010) studied images of the Russell crater dune field on Mars taken by the High Resolution Imaging Science Experiment from November 2006 to May 2009. They observ... (Geophysical Research Letters) [more]
Greenland ice loss spreading (19 March 2010)
The Greenland ice sheet has been losing mass at a significant rate during the past several years, contributing to global sea level rise. Recent studies show dramatic ice loss along the southeastern coast. Khan et al. (2010) combined Global Positioning System (... (Geophysical Research Letters) [more]
Ridge versus plume: A closer look at the seafloor south of Iceland (19 March 2010)
Host to many volcanoes, Iceland is generally thought to be fueled by a plume of hot mantle rising from the core-mantle boundary. It also sits atop the Mid-Atlantic Ridge, the plate boundary where the North American plate is spreading away from the Eurasian pla... (Geochemistry, Geophysics, Geosystems) [more]
Model explains increasing subtropical humidity in warming Earth (18 March 2010)
Global circulation model (GCM) experiments carried out for the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) predict that as the Earth undergoes global warming, humidity will increase in subtropical regions. Hurley and Galewsk... (Geophysical Research Letters) [more]
Wet spells getting longer in Europe (18 March 2010)
As the world's climate changes, precipitation patterns are changing as well. Previous studies have found that in Europe, the amount of precipitation has been increasing, and a new study shows an increase in the duration of wet periods, potentially affecting th... (Geophysical Research Letters) [more]
Explaining flotsam distribution inside and outside the surf zone (13 March 2010)
Beachgoers often notice that when debris gets into the ocean at a shore, some can be trapped floating near the shore while some is carried away from the surf zone. The distribution of flotsam is often observed to be patchy near the shore and streaky outside th... (Geophysical Research Letters) [more]
Wetlands influence regional rain patterns (12 March 2010)
Changes to water use upstream of wetlands could influence weather region-wide. One example is the Niger Inland Delta, a network of tributaries, channels, lakes, and swamps located in Mali just south of the Sahara desert. These wetlands typically appear in Sept... (Geophysical Research Letters) [more]
Carbon isotopes in coral skeletons reflect human-induced carbon dioxide changes (12 March 2010)
Carbon dioxide (CO2) produced from burning fossil fuels contains lower levels of 13C than naturally occurring atmospheric carbon dioxide contains. Thus, as humans burn fossil fuels, the ratio of 13C to other carbon isotopes (&d... (Geophysical Research Letters) [more]
Prolonged low solar activity will not offset global warming (10 March 2010)
Solar activity is known to influence Earth's temperature, and it has been suggested that the current period of low solar activity will lead into a more prolonged period of low activity, a new "grand minimum" similar to the Maunder minimum that lasted from 1645... (Geophysical Research Letters) [more]
Minimagnetosphere observed on the Moon (6 March 2010)
New observations using energetic neutral atoms show a minimagnetosphere on the Moon. Unlike Earth, the Moon does not have a global magnetic field and therefore does not have a magnetosphere surrounding it. However, the Moon does have small regions of magnetiza... (Geophysical Research Letters) [more]
Modeling groundwater age (5 March 2010)
Groundwater age, the amount of time groundwater has been in an aquifer, is important because the length of time water spends in an aquifer can influence many geologic processes. However, determining groundwater age—which can be as short as a few days or ... (Geophysical Research Letters) [more]
Model details river delta transformation (4 March 2010)
Various factors determine the dynamics of river delta systems. To examine in detail how river deltas form and transform, Geleynse et al. (2010) developed a high-resolution physics-based computer model. Their model takes into account boundary sedimentary compos... (Geophysical Research Letters) [more]
Tides in the thermosphere directly linked to the troposphere (19 February 2010)
The atmosphere has periodic oscillations that are driven by solar heating of the troposphere, the atmospheric layer closest to Earth's surface, where weather patterns form. Scientists have now observed that one of these atmospheric tides, known as diurnal wave... (Geophysical Research Letters) [more]
Laser mapping of fault scarps (18 February 2010)
Fault scarps, the visible topographic features caused by the motion of faults, can tell researchers about the history of fault motion. Fault scarps formed more recently tend to be sharper; older ones tend to have softened over time. Mapping fault scarps has be... (Geophysical Research Letters) [more]
Heat waves increasing in Mediterranean region (17 February 2010)
Heat waves have serious impacts on human health, agriculture, water resources, ecosystems, and energy use. Heat waves have been increasing as global temperatures rise, but most studies have focused on changes in maximum or average temperatures. Kuglitsch et al... (Geophysical Research Letters) [more]
Stirring up the ocean to store carbon? (16 February 2010)
With carbon dioxide (CO2) levels rising and the planet warming, various solutions are being considered to reduce atmospheric CO2 levels. One suggested geoengineering approach is to increase carbon sequestration by stirring up the oceans. ... (Geophysical Research Letters) [more]
Solar wind pressure drives away Mars's atmosphere (13 February 2010)
Mars is constantly losing parts of its atmosphere to space. The processes driving that loss of atmosphere are not completely understood. A new study shows that pressure from solar wind pulses is a significant contributor to Mars's atmospheric escape. Edberg et... (Geophysical Research Letters) [more]