Journal Highlights

Articles from across all AGU journals that have been selected by Editors because of their significant import to the geosciences.

Photochemistry complicates source attribution of volatile organic compounds (28 December 2012)

Understanding the sources of air pollution is important in mitigation efforts. Commonly used models known as receptor models often do not take into account chemical reactions that may occur between the source of the emission and the site where measurements are... (Journal of Geophysical Research - Atmospheres) [more]

August Arctic cyclone was strongest summer storm on record (15 December 2012)

For nearly 2 weeks in August 2012, a powerful cyclone churned the Arctic Ocean, driving down surface pressures and garnering significant public attention. Spawned over Siberia on 2 August, the storm, which came to be known as the "Great Arctic Cyclone of 2012,... (Geophysical Research Letters) [more]

More greenhouse gases needed to explain warm Archean Earth (15 December 2012)

During the Archean eon, from 3.8 to 2.5 billion years ago, life on Earth was thriving for the first time, growing in a world with much less land and a faster planetary rotation than today. At the same time, the energy flowing to the early Earth from the Sun wa... (Geophysical Research Letters) [more]

Assessing the uncertainties in flux measurements (14 December 2012)

Climate and environmental studies require knowledge of the exchange of carbon, water vapor, and energy between the atmosphere and terrestrial ecosystems. These exchanges are measured by tower instruments at numerous sites around the world using a technique kno... (Journal of Geophysical Research - Biogeosciences) [more]

A New State of Venus's Ionosphere (14 December 2012)

Observations from NASA's Pioneer Venus orbiter, which reached Venus in 1978, suggested that Venus's ionosphere had two states: a magnetized state with a large-scale horizontal magnetic field and an unmagnetized state with no large-scale magnetic field but with... (Geophysical Research Letters) [more]

Tropical cyclone waves detected with infrasound sensor array (13 December 2012)

The strong winds of a tropical cyclone whip up the sea surface, driving ocean waves a dozen meters high. When one such ocean wave runs into another wave that has an equal period but is traveling in the opposite direction, the interaction produces low-frequency... (Journal of Geophysical Research - Oceans) [more]

New satellite record of sea surface temperature (12 December 2012)

Sea surface temperature is one of the key variables scientists track in studying climate changes; it is also important to meteorology and oceanography. Merchant et al. (2012) describe a new 20-year record of sea surface temperature. The record was creat... (Journal of Geophysical Research - Oceans) [more]

Land area burned by fires 35% larger than previous estimates (11 December 2012)

The predominant technique for tracking wildfires uses repeat satellite observations to look for and measure the size of burn scars, the charred remains of once-lush terrain. Relying on moderate resolution imagery, however, this approach has a tendency to miss ... (Journal of Geophysical Research - Biogeosciences) [more]

Computationally inexpensive way to study windstorms on small scale (5 December 2012)

Windstorms are a major source of economic damage in Europe. To study their impacts on regional scales, scientists need large data sets of detailed, high-resolution wind field data. However, high-resolution regional simulations are computationally expensive. <... (Geophysical Research Letters) [more]

High pore pressure in seafloor related to slow slip earthquakes (1 December 2012)

Lying within the seafloor off the southern coast of southwestern Japan, the Nankai Trough is the surface expression of the subduction of the Philippine tectonic plate beneath the Eurasian plate. In the past, this fault has been responsible for producing large,... (Geophysical Research Letters) [more]

Initialized decadal climate model projects reduced future warming (30 November 2012)

Punctuating the long-term trends of global climate change are transient shifts driven by decadal or interannual natural variability. For instance, in the 1970s the Interdecadal Pacific Oscillation switched from its negative to positive mode, a change that spur... (Geophysical Research Letters) [more]

Topographic influences drive strong winds at Greenland's Cape Farewell (30 November 2012)

Jutting out into the northern Atlantic Ocean, the southernmost tip of Greenland—known as Cape Farewell—is the windiest oceanic site in the world, with gale-force winds whipping nearly a sixth of the time. The strong winds at Cape Farewell, called "... (Geophysical Research Letters) [more]

Ozone precursors have regionally variable effect on radiative forcing (29 November 2012)

When released near the surface, carbon monoxide, assorted nitrogen oxides (commonly referred to as "NO_x"), and nonmethane hydrocarbons (NMHC) contribute to the production of ozone, a key component of photochemical smog, which is known to have... (Geophysical Research Letters) [more]

Ionospheric vortices could explain Saturn's anomalous magnetic field (28 November 2012)

Thought to be produced by convection deep within the planet's interior, Saturn's magnetic field stands out among those of the solar system's gas giants in that it has a relatively simple structure and that it is nearly perfectly symmetrical about the planet's ... (Journal of Geophysical Research - Space Physics) [more]

Low-frequency radio emissions from high-altitude sprite discharge (27 November 2012)

When lightning strikes from a towering cumulonimbus cloud down to the ground, the electrical discharge can perturb the atmosphere's electric field, potentially triggering a second event—sprite discharge. This more elusive type of electrical discharge, wh... (Geophysical Research Letters) [more]

Everglades restoration could decrease carbon sink potential (20 November 2012)

Starting more than a century ago, and ramping up to a massive scale in the 1950s, canal building and drainage projects in the Florida Everglades steadily degraded the sprawling wetland ecosystem. In the coming years, a massive 30-year multibillion-dollar resto... (Journal of Geophysical Research - Biogeosciences) [more]

Statistical framework for assessing uncertainty in hydrological models (20 November 2012)

For regional managers trying to make long-term investments in hydrological infrastructure, having a reliable forecast of how their watershed may evolve in a changing climate is a significant boon. To make a projection of the regional effects of climate change,... (Water Resources Research) [more]

Dynamic Pressures in Porous Media (16 November 2012)

Understanding the relationship between fluid pressures and water content (saturation) in soils or other porous media can be important in a wide range of practical areas, including oil recovery, infiltration and flooding during extreme weather events, and envir... (Water Resources Research) [more]

Geomagnetic storms affect ozone in mesosphere (14 November 2012)

During geomagnetic storms, energetic electrons enter the upper mesosphere around 70 km above the Earth's surface. These energetic electrons enhance the chemical reactions that produce nitrogen oxides (NO_x) that can destroy ozone. If the nitrogen oxi... (Geophysical Research Letters) [more]

Dispersion model maps spread of Fukushima radiation (14 November 2012)

When water flooded the Japanese Fukushima Daiichi nuclear power plant on 11 March 2011, killing power to the plant and destroying its backup generators, the earthquake-triggered disaster resulted in the second major nuclear accident on record, with the plant p... (Journal of Geophysical Research - Oceans) [more]

Antarctic sea ice thickness affects algae populations (10 November 2012)

In the waters off Antarctica, algae grow and live in the sea ice that surrounds the southern continent—a floating habitat sure to change as the planet warms. As with most aquatic ecosystems, microscopic algae form the base of the Southern Ocean food web.... (Geophysical Research Letters) [more]

Estimating the size of 869 C.E. quake in region hit by 2011 Tohoku quake (9 November 2012)

The catastrophic 2011 magnitude 9 Tohoku earthquake, which triggered a huge tsunami that led to severe flooding and major destruction, was unexpected based on seismic hazard assessments for the Sendai region—for instance, a Japanese national seismic map ... (Geophysical Research Letters) [more]

First satellite detection of volcanogenic carbon monoxide (9 November 2012)

Measuring and tracking the gases that vent from an erupting volcano is a project wrought with potential dangers and difficulties. On the ground measurements place researchers in harm's way, as do airborne sampling surveys. These approaches may also suffer from... (Geophysical Research Letters) [more]

Debating how to assess hydrological model uncertainty and weaknesses (6 November 2012)

The projections of hydrological models, as numerical abstractions of the complex systems they seek to represent, suffer from epistemic uncertainty due to approximation errors in the model, incomplete knowledge of the system, and, in more extreme cases, flawed ... (Water Resources Research) [more]

Chamber measurements find plants potentially important methane sink (6 November 2012)

As a greenhouse gas, methane has a much higher heat-trapping potential than carbon dioxide when considered over the course of a few decades. In recent years, researchers discovered a potentially important new source of atmospheric methane—emissions from ... (Geophysical Research Letters) [more]

Global ocean salinity changing due to anthropogenic climate change (2 November 2012)

Rising sea surface temperatures, climbing sea levels, and ocean acidification are the most commonly discussed consequences of anthropogenic climate change for the global oceans. They are not, however, the only potentially important shifts observed over recent ... (Geophysical Research Letters) [more]

Regional Shifts in Snowfall, Melt, in the Intermountain West (1 November 2012)

The freshwater supplies of the American West rely, for the most part, on snow. The Colorado River, the Rio Grande, and other rivers in the intermountain west—the area bounded by the Sierra Nevada and Cascade mountains to the west and the Rockies to the e... (Water Resources Research) [more]

High-Frequency Flux Transfer Events Detected Near Mercury (30 October 2012)

The physical process that creates connections between the magnetic fields emanating from the Sun and a planet—a process known as magnetic reconnection—creates a portal through which solar plasma can penetrate the planetary magnetic field. The openi... (Journal of Geophysical Research - Space Physics) [more]

Regional Models Do Not Add Much Value to Climate Change Projections (27 October 2012)

Global general circulation models are the dominant tool in the effort to forecast the effects of climate change. Given their expansive scope, some simplifications need to be made when representing smaller-scale processes, such as the effects of regional topogr... (Journal of Geophysical Research - Atmospheres) [more]

Studying dynamics of soil moisture patterns (27 October 2012)

Soil moisture variations in space and time are important to the hydrological cycle. To better understand the dynamics of the various factors affecting soil moisture patterns, Rosenbaum et al. (2012) conducted a comprehensive study in the small Wüs... (Water Resources Research) [more]

Voyager observes magnetic field fluctuations in heliosheath (27 October 2012)

As they near the outer reaches of the solar system, for the past several years the two Voyager spacecraft have been sending back observations that challenge scientists' views of the physics at the edge of the heliosphere, the bubble created by charged particle... (Journal of Geophysical Research - Space Physics) [more]

Near-total surface melt detected on the Greenland Ice Sheet (27 October 2012)

On 12 July 2012, 98.6% of the surface of the Greenland Ice Sheet (GIS) melted, an event so expansive that a similar episode had not previously been seen in the satellite era. Ice core records indicate that the most recent melting event of this scale was 123 ye... (Geophysical Research Letters) [more]

Soft electron precipitation explains thermosphere mass enhancements (26 October 2012)

From 2000 to 2010, a German satellite carrying the Challenging Minisatellite Payload (CHAMP) orbited the Earth, tracking the properties of the thermosphere—the atmospheric layer that starts roughly 90 km above the surface and coincides with the lower lay... (Geophysical Research Letters) [more]

Clouds could explain how Snowball Earth thawed out (25 October 2012)

Glaciation events during the Neoproterozoic (524–1,000 million years ago) and Paleoproterozoic (1,600–2,500 million years ago) periods—events that spawned ice ages that persisted for millions of years at a time—may have seen glacier ice... (Geophysical Research Letters) [more]

Sunlight-reflecting potential of aerosols overestimated (20 October 2012)

Research into the role of aerosols in the atmospheric energy budget has predominantly been carried out in locations with high total aerosol loads. Less well understood are the effects of aerosols in relatively aerosol-free regions. By measuring the concentrati... (Geophysical Research Letters) [more]

Tree canopy creates ongoing reservoir for Fukushima radiation (19 October 2012)

When an earthquake-triggered tsunami destabilized the Fukushima Daiichi nuclear power plant in Japan in March 2011, authorities established a 20-km exclusion zone around the failed reactors—a safeguard against the highest-radiation concentrations. Radioa... (Geophysical Research Letters) [more]

Hydrological resilience and how catchments can switch steady states (16 October 2012)

If a system has a positive feedback, then it may have multiple stable states, or attractors, and finite resilience. Traditional techniques to calculate system resilience to outside pressures revolve around identifying the system state at a transition point and... (Water Resources Research) [more]

Decompression wave caused eruption chain reaction (13 October 2012)

The 2010 eruption of Iceland's Eyjafjallajökull proceeded through fits and starts. A new analysis by Tarasewicz et al. (2012) suggests that a downward propagating decompression wave triggered a cascade of explosive eruptions from sequentially deepe... (Geophysical Research Letters) [more]

Extreme-Pressure Research Explores How Earth's Mantle Solidified (12 October 2012)

During the earliest stages of the Earth's formation, the planet's mantle may have taken the form of a giant magma ocean, being fully or partially molten all the way down to the core-mantle boundary. Though today mantle material is predominantly solid, some sci... (Journal of Geophysical Research - Solid Earth) [more]

New estimate of volume of glaciers worldwide (11 October 2012)

As climate warms, melting mountain glaciers are likely to significantly contribute to sea level rise over the next decades, but how much they will contribute remains uncertain, as the total volume of Earth's mountain glaciers is not precisely known. Some ... (Journal of Geophysical Research - Earth Surface) [more]

Satellite Failures Revisited (10 October 2012)

In January 1994, two geostationary satellites, known as Anik-E1 and Anik-E2, operated by Telesat Canada, failed one after another within a 9-hour span, leaving many northern communities without television and data services. The outage, which shut down much of ... (Space Weather) [more]

Micro-topography creates biogeochemical hotspots in wetlands (10 October 2012)

Interventions in wetlands could improve water quality, as wetlands regulate not only nutrients such as nitrogen and sulfur but also pollutants in the waters that flow through them. Biological and chemical processes maintain conditions for redox reactions in th... (Journal of Geophysical Research - Biogeosciences) [more]

Spring snow cover loss exceeds model predictions (10 October 2012)

Spring snow cover extent in the Northern Hemisphere has declined to record lows in recent years, Derksen and Brown (2012) report. They analyzed spring (April–June) snow cover extent from the National Oceanic and Atmospheric Administration snow cha... (Geophysical Research Letters) [more]

Global tropical cyclone activity to decrease with climate change (10 October 2012)

Given its strong dependence on sea surface temperatures and atmospheric conditions, tropical cyclone activity is expected to be strongly affected by climate change. With observational records suggesting that tropical North Atlantic hurricane activity has incre... (Geophysical Research Letters) [more]

Most high-energy particle injections do not reach geostationary orbit (6 October 2012)

The injection of high-energy particles into the inner magnetotail is often considered a reliable sign of a magnetic substorm. These injections are often thought to be caused by flow bursts, short-lived periods of narrow fast flow streams in the magnetotail. An... (Journal of Geophysical Research - Space Physics) [more]

Water crises—a new approach (5 October 2012)

Water crises are one the biggest challenges facing humanity in the 21^st century. But what exactly is the nature of the crises? Scientists investigate the underlying causes driving water scarcity in 22 of the best studied cases across India, China, S... (Water Resources Research) [more]

A probabilistic method of predicting landslides (5 October 2012)

Heavy rainfall events can lead to devastating landslides, but predicting when rainfall will cause a landslide is challenging. Most current landslide prediction methods consider past rainfall events that resulted in landslides, and then use that as input to pr... (Journal of Geophysical Research - Earth Surface) [more]

The 11-Year Solar Cycle Continues Even During Prolonged Sunspot Minima (5 October 2012)

Streaming into the solar system at nearly the speed of light, galactic cosmic rays (GCRs) are a high-energy mix of protons, electrons, and atomic nuclei. As they pass into reach of the outflowing solar wind, the propagation of GCRs is inhibited. Galactic cosmi... (Geophysical Research Letters) [more]

Century-long trend of global ocean warming identified (5 October 2012)

One of the largest sources of uncertainty in reconstructing the warming of the past century stems from problems with historical ocean temperature records. Inconsistencies in method or technology or gaps in observation caused by two world wars mean that long-te... (Geophysical Research Letters) [more]

La Niña Caused Global Sea Level Drop (4 October 2012)

The 2011 La Niña was so strong that it caused global mean sea level to drop by 5 millimeters, a new study shows. Since the early 1990s, sea level has been rising by about 3 millimeters per year, satellite data show. But between the beginning of 2010 and... (Geophysical Research Letters) [more]

Characterizing the surface composition of Mercury (3 October 2012)

The MESSENGER spacecraft, which has been orbiting Mercury since March 2011, has been revealing new information about the surface chemistry and geological history of the innermost planet in the solar system. Weider et al. (2012) recently analyzed 205 mea... (Journal of Geophysical Research - Planets) [more]

Global precipitation variability decreased from 1940 to 2009 (2 October 2012)

One of the strongly held assumptions of climate change is that the variability of precipitation will grow with an increase in temperature. Storms will become heavier but less frequent. Flash floods and droughts will increase. Regions that see extensive rainfal... (Geophysical Research Letters) [more]

Central European Summer Temperature Variability to Increase (2 October 2012)

More extreme heat waves have been observed in central Europe in recent years as summer temperature variability has increased on both daily and interannual timescales. Models project that as the climate warms throughout the 21^st century, this increas... (Geophysical Research Letters) [more]

Troughs on asteroid Vesta are evidence of tectonics (29 September 2012)

Images from the Dawn spacecraft, which approached the asteroid Vesta in July 2011, show large-scale linear troughs on the asteroid's surface. To find out more about how these structures may have formed, Buczkowski et al. (2012) analyzed their sizes and ... (Geophysical Research Letters) [more]

Carbon dioxide and past Antarctic temperature linked (28 September 2012)

Antarctic ice core records indicate a strong connection between a rapid rise in temperature and a rapid increase in atmospheric carbon dioxide (CO₂) that occurred during the last ice age. Ahn et al. (2012) analyzed the carbon dioxide content ... (Geophysical Research Letters) [more]

Simple formulas calculate cloud droplet concentration (26 September 2012)

Droplets in clouds form on atmospheric aerosols known as cloud condensational nuclei. More than 90% of cloud droplets nucleate within a few tens of meters above the base of clouds, where the air is supersaturated. The microphysical processes of drop formation ... (Journal of Geophysical Research - Atmospheres) [more]

A statistical basis for multiobjective calibration (25 September 2012)

Mathematical models are very powerful tools for improving the understanding of environmental systems. However, the output of such models usually deviates systematically from observations, and this bias is typically larger than the measurement error. These prob... (Water Resources Research) [more]

Novel observations of currents and drag generated by a tsunami (22 September 2012)

Tsunamis cause damage even after they have traveled thousands of kilometers from their sources, and much of the damage is through generation of local strong currents. Even though wave heights of tsunamis that have traveled long distances are no greater than th... (Journal of Geophysical Research - Oceans) [more]

Linking typhoon tracks with rainfall patterns and flood timing (22 September 2012)

Being able to predict the timing and amount of flooding during and following a hurricane or typhoon would improve early warning and mitigation efforts. However, variable typhoon tracks and interaction between typhoons and varied landscapes make flood predictio... (Water Resources Research) [more]

The pros and cons of trading water: A case study in Australia (21 September 2012)

Water is a commodity, and water rights can be freely traded in an open market. Proponents of the free market approach argue that it leads to the most efficient allocation of water resources, as it would for any other commodity. However, unlike some commodities... (Water Resources Research) [more]

New approach to understanding sediment transport (21 September 2012)

Sediment transport is an important factor in the evolution of river channels. Bed load sediment flux, defined as the volume of particles crossing a vertical surface per unit time per unit width, is a common way to describe sediment transport. However, quantify... (Journal of Geophysical Research - Earth Surface) [more]

Need to represent upper ocean turbulence in climate models (21 September 2012)

The ocean surface boundary layer—approximately the uppermost 100 meters of the ocean—is important in controlling the exchange of heat and gases between the atmosphere and the ocean, but, as Belcher et al. (2012) show, current climate models'... (Geophysical Research Letters) [more]

In California, 5 decades of decreasing emissions (14 September 2012)

Volatile organic compounds (VOCs), which are emitted by vehicles and are a leading source of air pollution, have been on the decline in Los Angeles, Calif., one of the densest and most poorly ventilated cities in the United States, a new study finds. Comparing... (Journal of Geophysical Research - Atmospheres) [more]

New insights into faster computation of uncertainties (14 September 2012)

Heavy computation power, lengthy simulations, and an exhaustive number of model runs—often these seem like the only statistical tools that scientists have at their disposal when computing uncertainties associated with predictions, particularly in cases o... (Water Resources Research) [more]

The Everglades still threatened by excess nutrients (14 September 2012)

Since 1985, a state agency has constructed and continues to maintain hundreds of square kilometers of wetlands built to regulate the amount of nutrients reaching the Everglades in southern Florida. But this is proving to be ineffective in controlling concentra... (Water Resources Research) [more]

Measuring diapycnal diffusion in the northeastern Atlantic (14 September 2012)

In the upper ocean, turbulence-driven mixing uses energy to drive water flows across density bands. The rate of this flow, called diapycnal diffusion, is thought to have a strong effect on circulation patterns by mediating the global meridional overturning cir... (Journal of Geophysical Research - Oceans) [more]

Model explains details of the fault rupture process in 2008 Wenchuan Earthquake (13 September 2012)

On 12 May 2008 the Wenchuan earthquake, a magnitude 7.9 event, killed nearly 70,000 people and displaced millions in western China. Drawing on the observations of the National Strong-Motion Observation Network System (NSMONS), a network of 460 seismic detector... (Geophysical Research Letters) [more]

New technique for surface exposure dating (12 September 2012)

A new technique that allows researchers to determine the amount of time a rock sample has been exposed to daylight could find many applications in geology and archaeology. The new method, pioneered by Sohbati et al. (2012), is based on optically stimu... (Journal of Geophysical Research - Solid Earth) [more]

Comparing secondary organic aerosol formation in two U.S. cities (12 September 2012)

Secondary organic aerosols (SOAs) form from the oxidation of volatile organic compounds (VOCs) in the atmosphere, and the composition and abundance of SOAs affect their effects on air quality, human health, and the planetary radiation budget. To investigate ho... (Journal of Geophysical Research - Atmospheres) [more]

Earthquake in Chile triggers tremors and slips in Mexico (11 September 2012)

Recently, scientists have observed that large earthquakes often trigger tremors in places far away, sometimes thousands of kilometers, from the epicenter. In a new study, researchers have now shown that a major earthquake in Chile could have also triggered &qu... (Journal of Geophysical Research - Solid Earth) [more]

Model suggests Earth is undergoing true polar wander (11 September 2012)

At various points throughout Earth's history, the planet's solid exterior has drifted about in relation to the planetary rotation axis. This solid body drift, which is known as "true polar wander," results in a wholesale shift in the orientation of E... (Journal of Geophysical Research - Solid Earth) [more]

A new remote sensing technique to measure global reservoir storage (5 September 2012)

Nearly 60% of the world's large rivers are affected by dams, with more than 33,000 large dams holding back upward of 8300 cubic kilometers of water across the planet. Though reservoirs are employed worldwide, helping to ensure regular access to fresh water, mi... (Water Resources Research) [more]

Coupled model identifies effect of ozone stress on vegetative growth (5 September 2012)

An intricate feedback system ties together the activity of vegetation and tropospheric ozone. Ground level ozone, drawn from the atmosphere through dry deposition, stresses plants, inhibiting their growth. Plants, in turn, release biogenic volatile organic com... (Journal of Geophysical Research - Biogeosciences) [more]

Remote monitoring of sediment load in ocean water (1 September 2012)

Using the Geostationary Ocean Color Imager (GOCI)—the world's first geostationary satellite sensor that can obtain observational data on ocean color every hour during the daytime—scientists are able to remotely monitor the amount of suspended s... (Journal of Geophysical Research - Oceans) [more]

African dust forms red soils in Bermuda (1 September 2012)

In Bermuda, red iron-rich clayey soil horizons overlying gray carbonate rocks are visually stunning topographical features. These red soils, called terra rossa, are storehouses of information not only on past local processes that crafted the topography of the ... (Journal of Geophysical Research - Earth Surface) [more]

Weighing the ocean with a single mooring (1 September 2012)

Scientists propose that it would be possible to measure changes in ocean mass with a single moored sensor. Changes in ocean mass, which can be caused by added water from melting ice sheets, are an important part of global sea level changes, which can also resu... (Geophysical Research Letters) [more]

Seal-mounted sensors measure seasonal flows under Antarctic ice (1 September 2012)

Scientists used sensors attached to the heads of seals to measure water temperatures in the Weddell Sea, Antarctica. Researchers have questioned whether flows of Warm Deep Water into the region from farther north might vary seasonally, but hostile Antarctic co... (Geophysical Research Letters) [more]

A more "level" mean sea surface height near Australia (29 August 2012)

The mean sea level (MSL) around Australia may appear to slope from north to south when compared to the geoid—the mean sea level if Earth's oceans were devoid of currents. Heights measured on land relative to MSL exhibit the same north to south slope. The... (Journal of Geophysical Research - Oceans) [more]

Geomagnetic excursions date early hominid migration to China (25 August 2012)

Global-scale geomagnetic reversals, which are periods when the direction of Earth's magnetic field flips, leave imprints in magnetic minerals present in sediments. But so do smaller-scale, even local, changes in Earth's magnetic field direction. Paleomagnetist... (Geochemistry, Geophysics, Geosystems) [more]

More water stored along major rivers during El Niño years (25 August 2012)

El Niño–Southern Oscillation (ENSO)—the semiperiodic climate event associated with warming sea surface temperatures off the coast of Peru—not only disrupts atmospheric circulations, dramatically altering weather patterns across the glo... (Geophysical Research Letters) [more]

Harsh European winters linked to sunspot minima (25 August 2012)

The Rhine, one of the largest rivers of central Europe, freezes only during the coldest winters. Between 1780 and 1963, there were 14 instances when the Rhine froze over in several places; 10 of those occurred when the number of sunspots was at a minimum, a ne... (Geophysical Research Letters) [more]

Uncertainties in atmospheric mixing affect warming predictions (23 August 2012)

Uncertainties in the rates of small-scale mixing of greenhouse gases in the upper troposphere–lower stratosphere, between about 10 and 20 kilometers above Earth's surface, may be affecting predictions of how warm the Earth's surface could get i... (Journal of Geophysical Research - Atmospheres) [more]

China's Changbaishan volcano showing signs of increased activity (22 August 2012)

Roughly 1100 years ago, the Changbaishan volcano that lies along the border between northeastern China and North Korea erupted, sending pyroclastic flows dozens of kilometers and blasting a 5-kilometer-wide chunk off of the tip of the stratovolcano. The erupti... (Geophysical Research Letters) [more]

Annual Southern Ocean heat flux measured for first time (21 August 2012)

The Southern Ocean makes up nearly a quarter of the global ocean by surface area and plays a powerful role in regulating Earth's climate by affecting ocean and atmospheric circulation patterns. Modeled representations of the Southern Ocean, however, are plague... (Geophysical Research Letters) [more]

Low calcification in corals in the Great Barrier Reef (18 August 2012)

Reef-building coral communities in the Great Barrier Reef—the world's largest coral reef—may now be calcifying at only about half the rate that they did during the 1970s, although live coral cover may not have changed over the past 40 years, a... (Journal of Geophysical Research - Biogeosciences) [more]

Scientists observe fungi dissolving minerals (18 August 2012)

They live in moist dark recesses and never see daylight. But these ectomycorrhizal fungi (EMF), which cling to the roots of trees in boreal forests, break down soil minerals and supply essential elements and nutrients to the trees. Along the way, they play a d... (Journal of Geophysical Research - Biogeosciences) [more]

Technique improves ability to detect subsurface carbon dioxide leaks (15 August 2012)

One method to reduce atmospheric carbon dioxide concentrations is geologic carbon sequestration, often referred to as carbon capture and storage (CCS). In CCS, carbon dioxide is stored within stable geologic formations deep underground. Part of implementing CC... (Geophysical Research Letters) [more]

Solar storms can destabilize power grids at midlatitudes (11 August 2012)

The Sun is capable of disrupting electrical systems on Earth in a variety of ways, from solar flares and coronal mass ejections to proton storms. Typically, it is only objects far above the Earth's surface, or systems at high altitudes at polar latitudes, that... (Space Weather) [more]

Hotter days and droughts to continue through the 21^st century (10 August 2012)

As heat waves become more frequent, and droughts cause famines and drive up food prices, climate policies will need to account for changes in extremes in temperature and precipitation, as global mean temperatures continue to rise through the 21^st ce... (Journal of Geophysical Research - Atmospheres) [more]

Altitude controls carbon dioxide in boreal lakes (7 August 2012)

Organic matter present in lakes, derived either from land-based sources (e.g., plants, soil, sediments) or from in situ processes (e.g., degrading detritus in the water), could be an important player in the global carbon cycle or even a significant source of t... (Journal of Geophysical Research - Biogeosciences) [more]

Large melt channels discovered underneath Antarctic ice shelves (3 August 2012)

New radar observations reveal melt channels 500 m to 3 km wide and up to 200 m deep underneath the ice shelf buttressing the Pine Island Glacier in West Antarctica; researchers suggest that the subglacial channels could be a "prelude to eventual collapse" of t... (Journal of Geophysical Research - Earth Surface) [more]

Sea salt particles react with organic acids in atmosphere (2 August 2012)

Sea salt (sodium chloride, NaCl) particles lofted into the atmosphere by the motion of waves affect atmospheric chemistry; they can undergo reactions with trace atmospheric gases and internal mixing with anthropogenic pollutants depositing on particle surface.... (Journal of Geophysical Research - Atmospheres) [more]

Summarizing the field of surrogate modeling research (31 July 2012)

As computer simulations of complex physical interactions grow, so do the time and expense required to operate them. Mirroring the development of such full-scale models has been the related field of surrogate modeling or metamodeling. Surrogate models take a va... (Water Resources Research) [more]

Warmer daily temperatures since 1951 (31 July 2012)

Days and nights have indeed become warmer over the past 60 years, a new study finds. Although several observation-based studies have shown that both daily average temperatures as well as daily maximum and minimum temperatures have increased over the past few d... (Geophysical Research Letters) [more]

Balloon-borne sensor finds equatorward thermospheric wind (31 July 2012)

Emanating from atomic oxygen in the thermosphere, the faint light of airglow means that Earth's atmosphere is never completely dark. More than that by measuring subtle shifts in airglow's observed frequency researchers have developed a method to track the moti... (Geophysical Research Letters) [more]

Submesoscale dynamics: Bringing physics to life (27 July 2012)

Vertical motions play a key role in primary production in the upper ocean, as they transport nutrients that phytoplankton need to grow. Until recently scientists believed that three main types of dynamics dominated vertical motions in the upper ocean: mesoscal... (Geophysical Research Letters) [more]

Desert dust deposition reduces snow cover in Colorado Mountains (26 July 2012)

Dust deposition on the mountains of southwest Colorado may have reduced springtime snow cover by 1–2 months per year, a new study finds. When dust is deposited on snow surface, it increases absorption of solar radiation, accelerating snowmelt. Increasing... (Water Resources Research) [more]

Plasmaspheric hiss amplification mechanisms identified (25 July 2012)

Over the past 3 decades the hypothesis that chorus waves, a form of high-intensity plasma wave often found in the outer magnetosphere, evolve into plasmaspheric hiss in the plasmasphere has grown in prominence. Plasmaspheric hiss is a form of low-frequency rad... (Geophysical Research Letters) [more]

Long-term global hurricane activity record shows periodic highs and lows (24 July 2012)

In the long-term record of hurricane activity, which stretches back roughly 7500 years, the frequency of large tropical cyclones has drifted, with distinct periods of elevated or depressed activity lasting hundreds to thousands of years. Of the 12 sites that p... (Geophysical Research Letters) [more]

Lithospheric mantle thickness gradient focuses seismic activity (21 July 2012)

Using an array of 556 seismic sensors, Levander and Miller (2012) charted two key features of the subsurface structure of the western continental United States, with implications for explaining the locations of seismic and volcanic activity. Diving down... (Geochemistry, Geophysics, Geosystems) [more]

No change in African dust transport over past 45 years (19 July 2012)

The long-distance transport of dust around the planet has important implications for ecosystem stability and global climate dynamics. In some cases, most prominently the vast Amazon rainforest, travelling dust is the primary source of iron and phosphorous to o... (Geophysical Research Letters) [more]

Comparison with observations shows cloud simulations improving (18 July 2012)

Climate projections, such as those used by the Intergovernmental Panel on Climate Change, rely on models that simulate physical properties that affect climate, including clouds and water vapor content. Clouds and water vapor are difficult to simulate in global... (Journal of Geophysical Research - Atmospheres) [more]

Forest fires may cause cooling in boreal Canada (14 July 2012)

As climate in North America continues to become warmer and drier through the twenty first century, fire, a common and widespread hazard, may be playing an increasingly important role in shaping the climate of the boreal regions of Canada, a new study finds. Fo... (Geophysical Research Letters) [more]

Active sand dunes are largest dust source in the Sahara Desert (12 July 2012)

Dried up lakebeds and playas in the Sahara Desert of North Africa are large sources of dust in the atmosphere. For example, the Bodélé Depression at the southern edge of the Sahara Desert is the single largest source of dust in the world; on average,... (Geophysical Research Letters) [more]

Nitrogen oxide pollution from aircraft to increase by 2050 (12 July 2012)

The transportation industry is not only one of the biggest sources of air pollution and a significant player in greenhouse gas–induced global warming, but, as a new study shows, the industry could also be responsible for episodes of ozone (O₃)... (Geophysical Research Letters) [more]

Japan's 2011 tsunami created gravity waves in the ionosphere (12 July 2012)

On 11 March 2011, when a 9.0 magnitude earthquake triggered a catastrophic tsunami off the northern coast of Japan, a network of GPS receivers present near the epicenter of the earthquake detected perturbations in the total electron content (TEC) in the ionosp... (Radio Science) [more]

New measurements quantify atmospheric greenhouse effect (11 July 2012)

In spite of a large body of existing measurements of incoming short-wave solar radiation and outgoing long-wave terrestrial radiation at the surface of the Earth, and more recently, in the upper atmosphere, there are few observations documenting how radiation ... (Geophysical Research Letters) [more]

Atmospheric carbon dioxide drove climate change during longest interglacial (7 July 2012)

Known as the marine isotope stage 11 (MIS 11), the interglacial period centered around 400,000 years ago was the longest and possibly the warmest interglacial in the past 0.5 million years. Because the orbital configurations, atmospheric greenhouse gas concent... (Journal of Geophysical Research - Atmospheres) [more]

Dams impact carbon dynamics in U.S. rivers (3 July 2012)

Dissolved organic carbon (DOC)—which leaches into freshwater systems from plants, soils, and sediments, and from other detritus present in the water itself—is the major food supplement for microorganisms and plays an important role in several envir... (Journal of Geophysical Research - Biogeosciences) [more]

Monsoons intensify with peak sunspot activity (3 July 2012)

Scientists are increasingly pointing toward a strong connection between sunspots and climate, driven by what appears to be a coupled response of the atmosphere all the way from Earth's surface through the stratosphere. Sunspots are dark areas that develop temp... (Geophysical Research Letters) [more]

The random walk of tracers through river catchments (30 June 2012)

River catchments play critical roles in regional economies and in the global economy. In addition, rivers carry large volumes of nutrients, pollutants, and several other forms of tracers into the ocean. An intricate system of pathways and channels, both on the... (Water Resources Research) [more]

Tropical instability waves linked to sea surface salinity anomalies (29 June 2012)

Stretching westward from the South American coast, a tongue of cold water straddles the equator, reaching at times clear across the Pacific Ocean. The behavior of this cold tongue affects the marine ecosystem within its reach and influences the global climate ... (Geophysical Research Letters) [more]

New findings expand Apollo observations of lunar atmosphere (27 June 2012)

In December 1972 the astronauts of Apollo 17—the last manned mission to the moon—deployed the Lunar Atmospheric Composition Experiment (LACE), a spectrometer designed to measure and characterize the thin lunar atmosphere. Forty years later, Ster... (Geophysical Research Letters) [more]

Recent advances in turbulence prediction (23 June 2012)
Turbulence in the upper troposphere and the lower stratosphere (8–14 km in altitude) is a well-known aviation hazard; it is the major cause of injuries, and occasional fatalities, to passengers and crew members on commercial aircraft. Jet streams, thunde... (Geophysical Research Letters) [more]

High sulfide weathering in Taiwanese river basins (22 June 2012)
The emergence of the global sulfur cycle approximately 2.8 billion years ago is often associated with the beginning of life on Earth. Oxidation of sulfide-rich minerals, such as pyrites, to form sulfate (SO₄^2–) is an important part ... (Geophysical Research Letters) [more]

Present not the key to the past in tidal environments? (22 June 2012)
Landforms often retain evidence of erosional patterns and the climatic condition of the past. However, both the modern environment, determined by local changes in mean sea level, as well as past climate mold landforms in tidal environments such as estuaries an... (Geophysical Research Letters) [more]

Velocity shear layers in solar winds affect Earth's magnetosphere (22 June 2012)
Human society is increasingly reliant on technology that can be disrupted by space weather. For instance, geomagnetic storms can cause high-latitude air flights to be rerouted, costing as much as $100,000 per flight; induce errors of up to 46 m in GPS systems;... (Journal of Geophysical Research - Space Physics) [more]

Local factors important for water availability (19 June 2012)
One important issue that has grabbed the attention of scientists and policy makers alike is the amount of freshwater that will be available to populations across different climate settings, especially as rain belts reorganize in response to warming temperature... (Water Resources Research) [more]

Understanding ionospheric instabilities eludes current approaches (13 June 2012)
Ionized gases are heavily concentrated in the ionosphere's F zone, the region between 200 and 500 km in altitude, which is critical for transmitting long-distance radio signals on Earth. However, instabilities in the F region plasma, which can la... (Geophysical Research Letters) [more]

Atmospheric moisture residence time affects rainwater isotope ratios (13 June 2012)
The water cycle is expected to respond to rising air temperature, which redistributes moisture in the lowest part of the atmosphere, known as the boundary layer. To understand how boundary layer processes redistribute rainfall across different climate settings... (Geophysical Research Letters) [more]

Atmospheric turbulence not simply two-dimensional or three-dimensional (8 June 2012)
A complete mathematical description of turbulence is one of the most sought after prizes in physics, and though the research of Pinel et al. (2012) does not provide such a full account it does aim to pin down the answer to one subset of that effort: Are... (Geophysical Research Letters) [more]

Nonbreaking waves cause near-surface turbulence (7 June 2012)
Surface ocean turbulence is predominantly generated by two forces: near-surface winds and breaking waves. Where waves crash, strong downwelling can induce mixing of the upper few dozen meters, while winds establish larger turbulent vortices. A third known mech... (Journal of Geophysical Research - Oceans) [more]

Improved short-term forecasting of space weather (6 June 2012)
Geomagnetic disturbances caused by solar activity, known as space weather, can disrupt satellite communications and damage power grid equipment. Forecasts can give satellite operators and electrical transmission line companies time to take action to protect th... (Space Weather) [more]

Peat-based climate reconstructions run into murky waters? (5 June 2012)
Peatlands are globally important ecosystems that serve as archives of past environmental change. Peatlands form over thousands of years from the accumulation of decaying plants and hold water, or in some cases purely rainwater. Hence, both external processes, ... (Geophysical Research Letters) [more]

No evidence of polar warming during penultimate interglacial (5 June 2012)
The Atlantic Meridional Overturning Circulation (AMOC), driven by temperature and salinity gradients, is an important component of the climate system; it transfers an enormous amount of heat via ocean currents and atmospheric circulation to high northern latit... (Geophysical Research Letters) [more]

Streamflow changes following the 2010 Chile earthquake (5 June 2012)
Changes in streamflow and groundwater levels are known to occur following earthquakes. But the mechanisms for the changes in streamflow are not fully understood and vary from one location to another. Mohr et al. (2012) investigated streamflow response i... (Journal of Geophysical Research - Earth Surface) [more]

Italian super-eruption larger than thought (30 May 2012)
Recent research suggested that the super-eruption of the Campi Flegrei caldera volcano in southern Italy about 40,000 years ago may have played a part in wiping out, or forcing the migration of, the Neanderthal and modern human populations in the eastern Medit... (Geophysical Research Letters) [more]

Prediction system to protect astronauts from solar storms (25 May 2012)
With the impending solar maximum expected to bring heightened rates of flares and coronal mass ejections (CMEs), putting at risk an ever-increasing human presence in space, Oh et al. (2012) designed and assessed a prediction system to keep astronauts sa... (Space Weather) [more]

Section of thermohaline circulation driven by transient current rings (25 May 2012)
The southward branch of the Atlantic Meridional Overturning Circulation (AMOC), the stretch that carries deep, cold water from the North Atlantic to the Southern Ocean, predominantly flows along the eastern shoreline of the Americas. This deep water transport,... (Journal of Geophysical Research - Oceans) [more]

Area-based approach improves global sediment discharge modeling (23 May 2012)
By approaching the challenge of calculating global sediment discharge rates from a new angle, Pelletier (2012) developed a model that outperforms many existing simulations while minimizing the number of free parameters. Knowing how sediment is transport... (Journal of Geophysical Research - Earth Surface) [more]

Turbulent forces within river plumes affect spread (22 May 2012)
When rivers drain into oceans through narrow mouths, hydraulic forces squeeze the river water into buoyant plumes that are clearly visible in satellite images. Worldwide, river plumes not only disperse freshwater, sediments, and nutrients but also spread pollu... (Journal of Geophysical Research - Oceans) [more]

Tropospheric gas at potentially toxic levels in air (21 May 2012)
Forest fires and emission of air pollutants, which include fumes from vehicles running on diesel and slow burning of coal and charcoal, release isocyanic acid in the troposphere. In 2011, scientists first detected isocyanic acid in the ambient atmosphere at le... (Journal of Geophysical Research - Atmospheres) [more]

Vegetation affects hillslope hydrodynamics (19 May 2012)
Hillslopes are an important part of the hydrological cycle because water from rainfall or snowmelt runs downhill to networks of streams. Understanding hillslope hydrological dynamics is important for flood and debris flow prediction. However, because hillslope... (Water Resources Research) [more]

What drives knickpoints to migrate upstream? (18 May 2012)
Mountain landscapes are shaped by tectonic uplift, which creates topography, and climate, which determines the rate at which erosion wears down upland areas. Networks of rivers and streams transmit both tectonic and climate signals to landscapes—on a fu... (Journal of Geophysical Research - Earth Surface) [more]

New images of complex structures underneath the Tibetan Plateau (18 May 2012)
The Tibetan Plateau contains some of the highest mountains in the world and was formed by the collision between the Indian and Eurasian plates beginning around 55 million years ago. Curious about how such elevated terrains form, Yue et al. (2012) used d... (Journal of Geophysical Research - Solid Earth) [more]

Langmuir circulation inhibits near-surface water turbulence (17 May 2012)
In the surface ocean, breaking waves are a major source of air bubbles and turbulent kinetic energy. During the presence of a consistent surface wind, these wave-generated bubbles, along with other surface material like seaweed or foam, can be drawn into long ... (Geophysical Research Letters) [more]

Abyssal plains heat exchange could explain global deficit (17 May 2012)
When researchers measure the amount of heat flowing conductively from the seafloor to the ocean waters and then compare that value against a theoretical prediction of that heat loss, they observe that the global average measured heat flow is lower than expecte... (Journal of Geophysical Research - Solid Earth) [more]

A new and efficient approach to imaging underground hydraulic environments (16 May 2012)
To better locate natural resources, treat pollution, and monitor underground networks associated with geothermal plants, nuclear waste repositories, and carbon dioxide sequestration sites, scientists need to be able to accurately characterize and image fluid s... (Water Resources Research) [more]

For first time, entire thermal infrared spectrum observed (16 May 2012)
The driving mechanism of the greenhouse effect, and the underpinning of modern anthropogenic warming, is the absorption, emission, and transmission of infrared radiation by atmospheric gases. The heat-trapping ability of a gas depends on its chemical compositi... (Geophysical Research Letters) [more]

Changing El Niño could reshape Pacific Ocean biology (16 May 2012)
Over the past few decades, the scientific understanding of El Niño has grown increasingly complex. Traditionally viewed as a periodic warming focused largely in the eastern equatorial Pacific Ocean, El Niño is associated with reduced productivity in ... (Geophysical Research Letters) [more]

Reanalyses find rising humidity in the Arctic but miss fine details (16 May 2012)
Direct, reliable observations of atmospheric conditions stretch as far back as the midseventeenth century, with otherwise consistent records being punctuated by periodic updates in methods, practitioners, and observational equipment. To bridge these shifts in ... (Journal of Geophysical Research - Atmospheres) [more]

Seasonal algae plays critical role in North Pacific carbon uptake (15 May 2012)
The role of the North Pacific Ocean as a net carbon sink may prove to be more precarious than previously thought as researchers work to isolate the contributions of biological and physical processes to air-sea gas exchange. Scientists have long known that phys... (Journal of Geophysical Research - Oceans) [more]

New images support proposal for water ice near Mercury's south pole (12 May 2012)
Two decades ago, radio telescope observations showed radar-bright features in Mercury's polar regions. The radar characteristics are similar to those of the icy satellites of Jupiter and at the south polar ice cap on Mars. The radar-bright spots on Mercury wer... (Geophysical Research Letters) [more]

Clouds continue to plague latest generation climate models (12 May 2012)
In anticipation of the 2013 publication of the Intergovernmental Panel on Climate Change's fifth assessment report, many in the climate modeling community came together in 2008 under the banner of the Fifth Coupled Model Intercomparison Project, an internation... (Geophysical Research Letters) [more]

Physical controls of rift interaction identified (12 May 2012)
Cutting into the surface of every continent, and even the faces of other planets, the valleys formed by lithospheric rifting are a distinctive marker of tectonic activity. Rifts form from a structurally weak segment of the brittle upper crust, when stress-indu... (Geochemistry, Geophysics, Geosystems) [more]

Wind may have driven avalanches on Martian dunes (10 May 2012)
In the sand dunes in the north polar sand sea of Mars, sand avalanches that appear as wedge-shaped alcoves can be seen above fan-shaped deposits. The avalanches, which are typically several meters across, are currently actively forming, with new alcoves showin... (Geophysical Research Letters) [more]

Clay anomaly responsible for Mexican slow slip earthquakes (9 May 2012)
Over the past decade, seismologists have uncovered a previously unknown class of earthquakes. Known as slow slip earthquakes (SSEs), these events are marked by their long duration, periodic or repetitive nature, and substantial, though harmless, increases in t... (Geophysical Research Letters) [more]

New corrections for skylight estimates (9 May 2012)
Skylight, also known as diffuse solar radiation, accounts for about 16% of the total solar radiation reaching the Earth's surface; the percentage varies depending on external factors, such as the angle of the Sun with respect to the zenith and the composi... (Journal of Geophysical Research - Atmospheres) [more]

Ross Ice Shelf air stream driven by polar vortex cyclone (8 May 2012)
The powerful air and ocean currents that flow in and above the Southern Ocean, circling in the Southern Hemisphere's high latitudes, form a barrier to mixing between Antarctica and the rest of the planet. Particularly during the austral winter, strong westerly... (Journal of Geophysical Research - Atmospheres) [more]

Groundwater depletion contributes to sea level rise (8 May 2012)
Groundwater depletion is contributing substantially to sea level rise and will likely continue to do so over the next several decades, according to a study by Wada et al (2012). Much of the groundwater extracted for irrigation, drinking, and other uses ... (Geophysical Research Letters) [more]

Commercial ocean liners could be equipped to track tsunamis (5 May 2012)
Though observational networks exist to provide warning of an impending tsunami, Foster et al. (2012) propose a way to improve observational ability at a relatively low cost when compared with ramping up the use of existing techniques. Triggered by shall... (Geophysical Research Letters) [more]

Charged nanograins in the Enceladus plume (4 May 2012)
Enceladus, which orbits Saturn in the planet's E ring, is one of the few geologically active moons in the outer solar system. It emits a large plume that contains water-ice dust grains. Hill et al. (2012) used instruments on the Cassini spacecraft to ob... (Journal of Geophysical Research - Space Physics) [more]

Large-scale observations of flows in the ionosphere (4 May 2012)
At midlatitudes in the ionosphere, just below the auroral region, narrow channels of strong westward flow have been observed. These flows, known as subauroral polarization streams (SAPS), are driven by pressure gradients in near-Earth space and are a manifesta... (Journal of Geophysical Research - Space Physics) [more]

Steady convection keeps Earth's magnetic field in balance (3 May 2012)
The onslaught of the solar wind on the Sun-facing side of Earth's magnetic field causes terrestrial magnetic field lines to break through magnetic reconnection. The persistent pressure of the solar wind pulls the field lines and the associated plasma around to... (Journal of Geophysical Research - Space Physics) [more]

Oxygen isotopes improve weather predictability in Niger (24 April 2012)
For the African nation of Niger, the effect of seasonal atmospheric variability on the weather is poorly understood. Because most residents rely on local agriculture, improving the predictability of seasonal weather and precipitation availability is crucial. I... (Geophysical Research Letters) [more]

How earthquake properties vary with depth (21 April 2012)
A new study shows systematically how seismic properties vary with depth. Lay et al. (2012) analyzed recent large and great earthquakes, including the 2004 Sumatra-Andaman (M_w 9.2), 2010 Chile (M_w 8.8), and 2011 Toho... (Journal of Geophysical Research - Solid Earth) [more]

Mercurial magnetic field waves measured by orbiting satellite (20 April 2012)
Researchers working with NASA's Mercury Surface, Space Environment, Geochemistry, and Ranging (MESSENGER) spacecraft report the frequent detections of Kelvin-Helmholtz (KH) waves at the edge of the innermost planet's magnetosphere. In six different sets of mag... (Journal of Geophysical Research - Space Physics) [more]

Plasma conditions at Saturn's magnetopause (20 April 2012)
Magnetized planets, including Earth and Saturn, are surrounded by a magnetosphere, a magnetic bubble that generally repels the solar wind. At Earth's magnetopause (the boundary of the magnetosphere), magnetic reconnection—the breaking and rejoining of ma... (Geophysical Research Letters) [more]

Annual Arctic sea ice less reflective than old ice (20 April 2012)
In the Arctic Ocean the blanket of permanent sea ice is being progressively replaced by a transient winter cover. In recent years the extent of the northern ocean's ice cover has declined. The summer melt season is starting earlier, the winter freeze is happen... (Geophysical Research Letters) [more]

Measuring the human contribution to atmospheric carbon dioxide (19 April 2012)
Although it is well established that humans are responsible for the modern increase in atmospheric carbon dioxide concentrations, the precise emission rates of carbon dioxide and other environmentally important gases are less well known. Traditionally, the rep... (Journal of Geophysical Research - Atmospheres) [more]

Winds influence Bering Shelf circulation (19 April 2012)
Circulation over the Bering Sea shelf and between the shelf and the adjacent deep basin affects the ecosystem through nutrient exchange, egg and larvae dispersal, and changes in temperature and salinity. Using numerical models and observations, Danielson et... (Geophysical Research Letters) [more]

Uranus's auroras observed from Hubble Space Telescope (14 April 2012)
New observations from the Hubble Space Telescope provide the first ever images of Uranus's auroras. The new observations, described by Lamy et al. (2012), are also the first unambiguous detections of Uranus's auroras since they were first discovered usi... (Geophysical Research Letters) [more]

Properties of solitary waves in Lake Constance (14 April 2012)
Solitary waves—large individual waves that can travel long distances holding their shape, when normal waves would tend to flatten out—occur in oceans and in lakes, both on the surface and as internal waves below the surface. In lakes, these waves c... (Journal of Geophysical Research - Oceans) [more]

Imaging hyporheic exchange (13 April 2012)
The dynamics of flow through the subterranean area at the base and along the sides of streambeds, known as the hyporheic zone, affect stream ecosystem dynamics, but researchers don't have a solid understanding of what controls the amount of hyporheic exchange.... (Water Resources Research) [more]

Measuring currents between North Atlantic and Nordic Seas (12 April 2012)
The fluxes of water from the North Atlantic to the Nordic Seas provide a measure of the water that flows into and out of the global ocean as part of the meridional overturning circulation. The meridional overturning circulation, which carries warm water in the... (Geophysical Research Letters) [more]

Cattle waste tops cars as source of Southern Californian smog (12 April 2012)
A new study shows that cows, not cars, are the more substantial source of ammonia that leads to ammonium nitrate in California's South Coast Air Basin, the smoggiest place in America. Within the region, which consists of the area surrounding and downwind of Lo... (Geophysical Research Letters) [more]

Changing pressure drives lake methane emissions (11 April 2012)
Within the fine-grained sediments of a lake bed, microbes feeding on carbon-rich organic matter can pump out substantial quantities of methane. Recent research has shown that this flow of methane, when combined with other forms of carbon emissions, is enough t... (Journal of Geophysical Research - Biogeosciences) [more]

Natural soil pipes release peat carbon to atmosphere (7 April 2012)
A significant amount of organic carbon and carbon dioxide is stored within the partially decomposed plant remains that make up peatlands in northern climates. If this carbon were released to the atmosphere, it could affect climate. In peatlands, soil pipes&mda... (Journal of Geophysical Research - Biogeosciences) [more]

Silicic acid biogeochemistry in the Gulf of California (5 April 2012)
Silicon is an essential nutrient for the growth of siliceous phytoplankton, which accounts for a significant amount of marine primary production. Constraints on silicic acid limit primary production and carbon export, so biogeochemical silicon cycling influenc... (Paleoceanography) [more]

Hurricane feedback research may improve intensity forecasts (5 April 2012)
Forecasts of a hurricane's intensity are generally much less accurate than forecasts of its most likely path. Large-scale atmospheric patterns dictate where a hurricane will go and how quickly it will get there. The storm's intensity, however, depends on small... (Geophysical Research Letters) [more]

Simulating a bubbly ocean (3 April 2012)
Bubbles form on the ocean surface when waves break and are an important part of air-sea gas transfer. They also affect the optical and acoustical properties of the near-surface ocean. Observations of oceanic bubbles are limited, and scientists do not yet fully... (Journal of Geophysical Research - Oceans) [more]

Active faults newly identified in Pacific Northwest (30 March 2012)
The Bellingham Basin, which lies north of Seattle and south of Vancouver around the border between the United States and Canada in the northern part of the Cascadia subduction zone, is important for understanding the regional tectonic setting and current high ... (Journal of Geophysical Research - Solid Earth) [more]

Simulating thermokarst lakes (30 March 2012)
Thermokarst lakes, which form from thawing permafrost, alter landscapes and hydrology and can release significant amounts of methane to the atmosphere. To learn more about the dynamics of thermokarst lakes, Kessler et al. (2012) created a three-dimensio... (Journal of Geophysical Research - Biogeosciences) [more]

In the Greek isles a volcano has awakened (30 March 2012)
In 1650 B.C.E., a series of massive volcanic eruptions decimated the ancient seafaring Minoan civilization. Over the next 4 millennia, the largely subaquatic Santorini caldera had a series of smaller eruptions, with five such events within the past 600 years, ... (Geophysical Research Letters) [more]

Voyager 1 measures electron intensity in the outer heliosphere (29 March 2012)
The Voyager 1 spacecraft is exploring the outer heliosheath past about 111 AU from the Sun. The heliosheath is the region where the outgoing solar wind is slowed by the interstellar medium. The Voyager spacecraft have been sending back interesting new informat... (Geophysical Research Letters) [more]

Inverted thermocline, circulation patterns found in Lake Erie (29 March 2012)
A series of high-resolution measurements has shown that Lake Erie, one of the North American Great Lakes, is, in some respects, backward. In the majority of thermally stratified lakes, the thermocline, a thin subsurface layer of rapid temperature change, is de... (Geophysical Research Letters) [more]

Measuring the biogeochemical response to pulses of water (24 March 2012)
Hydrologic pulses, temporary increases in water inputs such as bouts of precipitation, can affect biogeochemical processes in ecosystems by providing water and nutrient resources, but ecosystem responses to the water vary. Harms and Grimm (2012) conduct... (Journal of Geophysical Research - Biogeosciences) [more]

Seesaw does not explain Antarctic climate change (23 March 2012)
The Arctic has warmed rapidly in the past 3 decades, but temperature records show that the Antarctic on average has warmed less. This observation hints at a bipolar seesaw mechanism, in which changes in ocean circulation result in changes in heat transport bet... (Geophysical Research Letters) [more]

Satellite tracks seasonal changes in atmospheric heavy water (22 March 2012)
Ascending through the upper troposphere and lower stratosphere, from 10 to 30 km altitude, the steadily decreasing temperature causes water vapor containing the hydrogen isotope deuterium—HDO or heavy water—to preferentially condense out of the air... (Journal of Geophysical Research - Atmospheres) [more]

In calm seas, precipitation drives air-sea gas exchange (21 March 2012)
In a series of experiments run in what resembles a heavily instrumented fish tank, Harrison et al. (2012) investigated the interwoven roles of wind and rain on air-sea gas exchange rates. Working with a 42-m long, 1-m wide, and 1.25-m tall experimental ... (Journal of Geophysical Research - Oceans) [more]

Interdisciplinary technique helps model landslides (21 March 2012)
Much like tracking the flow of colored grains floating in turbulent water, determining the movements of a specific piece of earth on a landslide-prone surface is a challenging task. Though recent advances in three-dimensional surface mapping techniques have im... (Journal of Geophysical Research - Earth Surface) [more]

Gasoline contributes more than diesel fuel to secondary organic aerosol (20 March 2012)
Gasoline-powered vehicles contribute more to secondary organic aerosol formation than diesel-fueled vehicles do, a new study shows. Organic compounds in both gasoline fuel and diesel exhaust can lead to the formation of secondary organic aerosols, which negati... (Geophysical Research Letters) [more]

Fossilized plant matter indicates more recent Asian desertification (17 March 2012)
Roughly 22 million years ago, at the onset of the Miocene, the Tibetan Plateau started to lift upward. The rising land curbed the flow of moist air from the south, sparking the onset of central Asian desertification. Or, perhaps, the supposedly arid region to ... (Geophysical Research Letters) [more]

Reforestation efforts reshape Hawaii's soil hydrology (14 March 2012)
Starting with the arrival of Polynesian settlers in the fourth century, and peaking in the mid-1800s, the destructive forces of wildfires and pests and the grazing of feral pigs, goats, and cattle reduced the native forests of Maui, Hawaii, to just a tenth of ... (Geophysical Research Letters) [more]

Declining sea ice to lead to cloudier Arctic (13 March 2012)
Arctic sea ice has been declining over the past several decades as global climate has warmed. In fact, sea ice has declined more quickly than many models predicted, indicating that climate models may not be correctly representing some processes controlling sea... (Geophysical Research Letters) [more]

Tracking a Jurassic reversal of the Earth's magnetic field (13 March 2012)
Roughly 180 million years ago, during the height of the Jurassic period, the Earth's magnetic field flipped, bringing the magnetic north pole once again into the Northern Hemisphere. This so-called van Zijl reversal, named for the researcher who first describe... (Geochemistry, Geophysics, Geosystems) [more]

El Niño related to changes in sardine spawning (8 March 2012)
The Pacific sardine, an important species for commercial fishing, spawns off the coast of California. The area and quality of its spawning habitat have been observed to vary from year to year, sometimes changing with El Niño–Southern Oscillation c... (Journal of Geophysical Research - Oceans) [more]

Improving understanding of type III solar radio bursts (7 March 2012)
Solar radio bursts are associated with solar events that can interfere with GPS and communications systems, so scientists would like to learn more about the dynamics of these bursts. Type III solar radio bursts, which are generated when high-energy electrons a... (Geophysical Research Letters) [more]

How did the equatorial ridge on Saturn's moon Iapetus form? (7 March 2012)
Saturn's moon Iapetus is one of the most unusual moons in our solar system. Perhaps the most bizarre feature of Iapetus is its equatorial ridge, a 20-kilometer high, 200-kilometer wide mountain range that runs exactly along the equator, circling more than 75% ... (Journal of Geophysical Research - Planets) [more]

A general approach to spontaneous imbibition (7 March 2012)
Spontaneous imbibition occurs in a porous medium when, driven by capillary forces, a wetting fluid such as water displaces a nonwetting fluid like oil or air. This is a common phenomenon, relevant to many processes such as groundwater contamination, steam migr... (Water Resources Research) [more]

Improving understanding of geomagnetic substorms (6 March 2012)
Substorms, the frequent, brief magnetic disturbances that originate in Earth's magnetotail, cause acceleration of particles in the magnetosphere and their precipitation into the ionosphere, resulting in sudden brightening and increased movement and expansion o... (Geophysical Research Letters) [more]

Improving operational plume forecasts (6 March 2012)
Forecasting how plumes of particles, such as radioactive particles from a nuclear disaster, will be transported and dispersed in the atmosphere is an important but computationally challenging task. During the Fukushima nuclear disaster, operational plume forec... (Journal of Geophysical Research - Atmospheres) [more]

North American rivers a sizable source of atmospheric carbon (3 March 2012)
To fulfill the need for an ever more granular, accurate, and complete understanding of the flow of carbon through the Earth system, a flurry of research has taken place in the past decade on previously overlooked aspects of the carbon cycle. Researchers have i... (Journal of Geophysical Research - Biogeosciences) [more]

When will warming-induced rainfall changes be perceptible? (2 March 2012)
Global climate change is not only changing temperatures but also altering precipitation. These changes in precipitation have been studied on large regional levels, but studies have not been able to identify changes in observed precipitation on smaller spatial ... (Geophysical Research Letters) [more]

Regional models expect drier, stormier western United States (2 March 2012)
As the American southwestern states struggle against ongoing drought, and the northwest braces for a projected shift from a snow- to a rain-dominated hydrological system, climate researchers strive to provide precipitation projections that are fine grained eno... (Geophysical Research Letters) [more]

Laboratory analysis updates fault slip formula (29 February 2012)
The rate at which one rock slab slides past another, such as could be found in a fault or fracture, depends on the strengths of the applied forces and the friction between the blocks. Though simple in concept, accurately modeling the interactions—especia... (Journal of Geophysical Research - Solid Earth) [more]

Geomagnetic data reveal unusual nature of recent solar minimum (28 February 2012)
Since the mid-1800s scientists have been systematically measuring changes in the Earth's magnetic field and the occurrence of geomagnetic activity. Such long-term investigation has uncovered a number of cyclical changes, including a signal associated with 27-d... (Geophysical Research Letters) [more]

Land use changes contribute to climate extremes (25 February 2012)
Temperature extremes such as severe heat waves and cold spells are likely to occur more frequently in a warming climate as carbon dioxide (CO₂) concentrations rise. But land use change, such as clearing forests for agriculture, also has a large impa... (Journal of Geophysical Research - Atmospheres) [more]

Thermokarst lakes increased atmospheric methane levels (25 February 2012)
Greenland ice cores indicate that during the last deglaciation, approximately 10,000 years ago, increases in temperature occurred at the same times as increases in atmospheric methane, a potent greenhouse gas. The source of the increase in atmospheric methane ... (Journal of Geophysical Research - Biogeosciences) [more]

Model describes New Zealand's complex tectonic environment (22 February 2012)
At the Hikurangi fault, off the eastern coast of New Zealand's North Island, the Pacific tectonic plate sinks beneath the Australian plate. Farther south, in the Marlborough Fault System, which cuts through the country's larger South Island, the interaction be... (Journal of Geophysical Research - Solid Earth) [more]

Warming set stage for, but did not directly cause, deadly heat wave (22 February 2012)
In the summer of 2010, soaring temperatures and widespread forest fires ravaged western Russia, killing 55,000 and causing $15 billion in economic losses. In the wake of the record-setting heat wave, two studies sought to identify the contribution that human a... (Geophysical Research Letters) [more]

Efficiency of organic aerosols as cloud condensation nuclei (22 February 2012)
Secondary organic aerosols, aerosols produced through chemical reactions in the atmosphere from volatile compounds, affect climate directly by reflecting sunlight and by acting as cloud condensation nuclei, promoting cloud formation. The efficiency with which ... (Journal of Geophysical Research - Atmospheres) [more]

Persistent regional CO₂ anomalies driven by land use (21 February 2012)
Researchers have traditionally used measurements from remote locations, such as Hawaii's Mauna Loa Observatory and other isolated stations, to determine atmospheric carbon dioxide (CO₂) concentrations and estimate the strengths of various carbon sou... (Journal of Geophysical Research - Biogeosciences) [more]

Statistical technique seeks to reduce climate uncertainty (21 February 2012)
Three measures of the climate system—climate sensitivity, vertical ocean diffusivity, and sulfate aerosol forcing—underpin the current understanding of the power of anthropogenic climate change. Climate sensitivity reflects the equilibrium temperat... (Journal of Geophysical Research - Atmospheres) [more]

Early Eocene climate warming increased petroleum production (21 February 2012)
From the late Paleocene, about 58 million years ago, to the early Eocene, about 51 million years ago, Earth's surface temperatures warmed by about 5°–10°C. Also in the early Eocene, there was an increase of carbon-13-depleted carbon in the oceans... (Geophysical Research Letters) [more]

Active and passive microwave data improve soil moisture estimates (18 February 2012)
Assimilating satellite observations from active or passive microwave sensors into models can improve soil moisture estimates, a new study shows. Passive sensors detect radiation emitted naturally from the land surface, while active sensors emit a radiation pul... (Geophysical Research Letters) [more]

River bed transport measurements show bed dilation and contraction (17 February 2012)
A new study of bed load transport—the movement of the gravel or other grains on a stream bed—has turned up a previously undetected effect. Marquis and Roy (2012) used several different methods to monitor bed load activity in a gravel bed riv... (Journal of Geophysical Research - Earth Surface) [more]

Asian emissions contribute to air pollution in western United States (17 February 2012)
As Asian countries develop, they are emitting more ozone precursors that pollute surface level air. Many studies have documented this pollution being carried by air currents to the western United States. To learn more about the mechanisms that transport air po... (Journal of Geophysical Research - Atmospheres) [more]

Model estimates soil permeability using induced polarization (16 February 2012)
The speed at which water flows through the ground depends on a number of physical parameters, including the density of the soil and the number and sizes of open pores, with the cumulative effect of these parameters dictating the soil's permeability. When expos... (Water Resources Research) [more]

Effect of vegetation die-off on tidal marshland tested (14 February 2012)
Consisting of densely vegetated platforms raised slightly above sea level, and interwoven by channels of water meandering inland from the coast, tidal marshlands help buffer against strong storm surges, protect against flooding, limit coastal erosion, and prov... (Geophysical Research Letters) [more]

Measuring mercury in coastal fog water (11 February 2012)
Mercury, a heavy metal neurotoxin, accumulates in sea life, in some cases reaching levels that make seafood unsafe for humans to eat. How mercury gets into aquatic organisms is debated, but part of the pathway could include mercury carried in precipitation, in... (Geophysical Research Letters) [more]

Molecular oxygen ions confirm exosphere at Saturn's moon Dione (9 February 2012)
The Cassini spacecraft flew by Dione, one of Saturn's icy moons, on 7 April 2010. During that flyby, instruments detected molecular oxygen ions around the moon. Tokar et al. (2012) used those measurements to estimate the density of the molecular oxygen ... (Geophysical Research Letters) [more]

Bering Strait influences climate conditions (3 February 2012)
The Atlantic meridional overturning circulation (AMOC) acts as a heat conveyer belt, bringing warm tropical water northward in the Atlantic Ocean and carrying cold dense water back southward. Some previous studies have suggested that changes in AMOC could resu... (Geophysical Research Letters) [more]

Low-energy ions dominate Earth's, Mars', and Venus' space environments (1 February 2012)
Stretching from the top of the ionosphere out into space, the terrestrial space environment is packed with low-energy ions, populated when ultraviolet radiation emanating from the Sun ionizes atmospheric gases in the ionosphere below. These ions, with energies... (Geophysical Research Letters) [more]

Soil oxygen affects denitrification (1 February 2012)
Rates of denitrification, the metabolic process by which bacteria produce nitrogen (N₂) gas, are variable and difficult to measure in ecosystems. Burgin and Groffman (2012) sought to learn more about the influence of soil oxygen, which is not... (Journal of Geophysical Research - Biogeosciences) [more]

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]

Remote sensing of volcanic ash properties (28 January 2012)
Remote sensing is an important tool to track hazardous volcanic plumes, providing an overview of the ash cloud. Francis et al. (2012) describe a method of using infrared data from instruments onboard the Meteosat satellite to detect volcanic ash and der... (Journal of Geophysical Research - Atmospheres) [more]

Yellowstone's diverse hydrothermal activity stems from single source (28 January 2012)
Within Yellowstone National Park, the water emanating from the park's famous hot springs and geysers seems to belong to either one of two distinct types. In some areas, subterranean waters rich in chlorine and dissolved silicates burst from the ground to creat... (Geochemistry, Geophysics, Geosystems) [more]

Model investigation overthrows assumptions of watershed research (28 January 2012)
A 2009 study revealed serious flaws in a standard technique used by hydrological researchers to understand how changes in watershed land use affect stream flow behaviors, such as peak flows. The study caused academics and government agencies alike to rethink d... (Water Resources Research) [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]

Special section of GRL covers Tohoku earthquake (21 January 2012)
On 11 March 2011 a M_w 9.0 earthquake occurred off the coast of Japan's Tohoku region, causing a massive tsunami. The disaster resulted in more than 15,000 deaths and severe property destruction. A special section of Geophysical Research Le... (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 m^{2Geophysical 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 R_{S<... (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]

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