The Atmospheric Sciences Section studies the physics, chemistry, and dynamics of the atmosphere, particularly the two layers closest to Earth’s surface, the stratosphere and troposphere. These layers are crucial to life because they regulate the planetary surface temperature, play an integral role in the world’s water cycle, and screen the planet from high-energy radiation.

One of the most critical issues that section members are studying today, along with colleagues in other sections, is global climate change. Much research is focused on monitoring fluctuations in the ozone layer, aerosols, levels of gases, and the effects of emissions from human activities such as aircraft, industry, and fossil fuel and biomass burning. The purpose of much of this research is to provide information in support of policies designed to respond to atmospheric changes that stress the Earth system. The Montreal Protocol is one example of how atmospheric scientists have successfully influenced government policies for the protection of the environment. This international agreement, signed in 1987, phased out the manufacture of chlorofluorocarbons throughout most of the world.

The Biogeosciences section emphasizes linkages between biological sciences and geophysical sciences fundamental to study of the Earth and other planets. The research areas encompassed within the section include biogeochemistry, biogeophysics, astrobiology, and planetary scale ecosystem science. Section members are interested in advancing understanding of coupled biological and geophysical processes important in many emerging research areas in biology, ecology and earth and planetary science. Examples of such processes are terrestrial ecosystem-climate interactions, transport of contaminants in groundwater, effects of stream flow patterns on aquatic biodiversity, extinction events in Earth history and existence of life under extreme conditions on Earth or other planets.

Progress in these research areas will be relevant to current environmental challenges, such as climate change, regional scale nitrogen enrichment and contaminant regulation. The section welcomes members who are academic and research scientists.

The Geodesy Section is concerned with the study and measurement of the external shape and gravity field of the solid Earth, the oceans, and the major ice sheets, including their temporal variations. The construction of the Earth’s core and mantle as well as the internal dynamics and the exchange of angular momentum between these components are of interest to the section, especially their contribution to changes in Earth’s rotation. Geodetic measurements are crucial to the study of climate change, the advance and retreat of ice sheets and glaciers, sea level rise, and charting the motion of the Earth's crust through time.

Geodesists are constantly striving for more accurate measurements to complement their existing techniques, and today new, exciting technologies are expanding the possibilities of their research. Space techniques, such as very long baseline interferometry and laser ranging, which chart positions on Earth with unprecedented accuracy have been applied for more than a decade, but Global Positioning System receivers are now being installed for continuous monitoring of crustal motions, especially in seismically active areas. In addition, altimeters carried by satellites and aircraft are being used to monitor ocean topography, including ocean circulation and sea level, as well as variations in the polar ice sheets. The TOPEX/POSEIDON and ERS-1/2 satellites have returned a wealth of information using radar altimetry, and future satellite altimeters will further expand this base.

Members of the Geomagnetism and Paleomagnetism Section study the geomagnetic field, from its core to space, to gain an understanding of Earth’s structure, dynamics, and history. Geomagnetists measure the Earth’s magnetic field at present and use measurements taken over the past few centuries to devise theoretical models to explain its origin. Paleomagnetists have an eye to history: they interpret fossil magnetization in rocks and sediments from the continents and oceans, which record the spreading of the seafloor, the wandering of the continents, and the many reversals of polarity that Earth’s magnetic field has undergone through time.

Other key aspects of GP research are the physics and chemistry of magnetic minerals, which deal with how they are formed and become magnetized and shed light on ancient climate and environment; magnetic anomalies, which offer clues about the subsurface vital for understanding the crust; and electromagnetic induction, which delineates structures deep within the planet related to variations in composition, temperature, and other properties. Keeping track of changes in the magnetic field and providing free data to researchers through a global network of permanent geomagnetic observatories are also important to the section. Exciting developments at the forefront of GP research include breakthroughs in supercomputer geodynamo simulation that are, for the first time, producing Earth-like magnetic fields and giving new insights into the dynamics of the core and aeromagnetic surveys in Antarctica that are helping to determine the geology, lithospheric structure, and tectonic evolution below the ice.

Hydrologists study the occurrence, distribution, movement, and properties of water as a solid, liquid, and vapor, as it cycles through surface waters, the atmosphere, and the surface layers of the Earth. Hydrological inquiry involves almost all of the physical sciences, including physics, chemistry, geology, soil sciences, and meteorology, as well as engineering, the social sciences, and life sciences.

The Section’s scientific activities are administered by ten technical committees: Erosion and Sedimentation, Groundwater, History of Hydrology, Large-Scale Experimentation, Policy Sciences, Precipitation, Remote Sensing, Surface Water, Unsaturated Zone, and Water Quality. Thus members of the Hydrology Section study a variety of water-related issues and concerns such as the relationship of land-based surface water processes to weather and climate, including floods, droughts, and erosion; groundwater flow and the remediation of contaminated groundwater; and the characteristics and causes of water quality conditions.

Charged with exploring three fourths of the planet, the Ocean Sciences Section is necessarily large and inclusive. The section welcomes members whose primary interests are marine related, regardless of discipline, and it recently organized into four subsections that provide a clearer focus for participation in AGU activities: biological oceanography (BO), marine geochemistry (MG), marine geology and geophysics (MGG), and physical oceanography (PO).

Across these disciplines, members are academic and research scientists, engineers, policy-makers, and administrators. Members study processes in environments ranging from the coast through the open ocean, and they develop and use a wide range of highly technical instrumentation ranging from remote sensors to autonomous devices to ship-related sampling gear.

The oceans are important for our quality of life, its fisheries and mineral resources, for transport, and its role in the climate system. Some of the exciting research emerging is related to the role of the oceans in the climate system. Researchers are studying the ocean’s involvement in the exchange of heat, water vapor, and momentum; sequestering heat at depth; and exchange and cycling of greenhouse gases and other biogeochemically important compounds. Because of its broad focus—and because the ocean is such a vital part of the Earth system—the Section encourages dialogue with interdisciplinary scientists at the Spring and Fall Meetings and the biennial Ocean Sciences Meeting, which is jointly organized with other societies concerned with studying marine problems.

The science focus of the Planetary Sciences Section encompasses both basic research into how planets work as well as the planning and implementation of space missions for exploration and discovery. Because the Section involves all aspects of planetary science, it is very interdisciplinary. Members of the Section are interested in characterizing the current properties of the known planets and developing an understanding of the formation and diverse evolution of planetary systems (core, mantle, crust, surface, hydrosphere, atmosphere, exosphere, rings, and satellites).

The varied manifestation of planetary processes (volcanism, tectonics, impact cratering, geochemical evolution) continues to challenge our formulation of geophysical principles. Approaches include observation and analysis of remotely acquired data (accumulated largely from spacecraft), analytical and experimental laboratory analyses, and modeling and testing of the natural system. While Galileo and Cassini are ongoing programs to explore the outer planets, a variety of small spacecraft with focused objectives will also soon return new data for asteroids, Mars, a comet, and other bodies (yet to be selected).

The Seismology Section is concerned with the study of the Earth’s internal structure, its deep interior and dynamics, how the Earth was formed, and the physical phenomena that cause earthquakes. Seismologists draw upon the fundamentals of geology, material science, geodesy, and statistics. They use seismic waves to probe the internal structure of the Earth, applying fundamentals of wave propagation in complex media. As such, seismological findings contribute to the greater view of Earth as a dynamic system.

Exciting topics at the forefront of seismological research include the structure and dynamics of the Earth’s inner core, the seismic structure of the lithosphere, and the nucleation process of large earthquakes. Seismology attracts considerable public interest and support because of its contributions to society in mitigating earthquake hazards, monitoring nuclear explosions both for military intelligence and arms control, and finding oil. Now that seismology is a data-based science, modern seismology has many opportunities for people who take an analytical approach to the geophysical sciences, such as those skilled in classical physics, applied mathematics, time series analysis, and computer sciences.

The Space Physics and Aeronomy Section is united by its interest in the heliosphere, the region around the Sun that is permeated by the solar wind and the interplanetary magnetic field, and the upper atmospheres and magnetospheres of solar system planets and small bodies. To maintain the integrity of its scientific endeavors and to make participation in AGU activities more manageable, the Section is organized into three subsections.

Concerns of the Aeronomy (SA) subsection include the Earth’s ionosphere, thermosphere, and mesosphere, auroras and airglow, lightning, and planetary atmospheres and ionospheres. Researchers affiliated with the solar and heliospheric physics (SH) subsection study the solar wind, coronal heating, the interplanetary magnetic field, magnetic reconnection, collisionless shocks, and helioseismology. The magnetospheric physics (SM) subsection’s focus is on geomagnetic storms, magnetospheric substorms, the magnetic fields and currents of the magnetosphere, the magnetopause, and the magnetospheres of planets and small bodies in the solar system. All in the SPA Section share in the challenge to plan future space investigations that will lead to new discoveries. To generate excitement and understanding of space physics and aeronomy among the public, the SPA Section is involved in a number of educational initiatives.

The Tectonophysics Section is truly interdisciplinary, with ties to seismology, geodesy, planetology, geomagnetism/paleomagnetism, and volcanology. Its members cultivate an interest in geodynamical processes and deformation from the scale of individual crystals to mantle convection and plate tectonics through the study of rock mechanics, mineral physics, seafloor geology and morphology, continental and marine tectonics and structural geology, and the thermal regime and mass balance of the Earth.

An enduring challenge facing tectonophysicists is to relate processes and measurements at Earth’s surface to their origins at depths that can’t be directly observed. Better measurements, whether in the laboratory, at sea, in deep drill holes, or from satellites, are revealing unexpected complexity that often challenges simplified descriptions and standing models. This is nowhere better illustrated than in the continents, where basic issues like the strength of the lithosphere, strength of major plate boundary faults, the origins of the mountain belts, and the mechanics of intraplate seismicity remain unresolved.

The chemical and physical evolution of rocks and minerals, particularly igneous and metamorphic rocks, falls under the purview of the Volcanology, Geochemistry, and Petrology Section. Because of the Section’s interest in studying and mitigating the hazards of volcanoes, its work has a direct bearing on public safety and the preservation of life.

Research topics that dominate the Section include isotope geochemistry and geochronology, mafic and ultramafic rocks, mafic volcanism, metamorphism, magma dynamics, new geochemical methods of research, and even glacial cooling. Though the research interests of VGP members are diverse, they strive to solve cross-disciplinary problems within an effective framework and to make the results of that research widely available.

An important focus is the study of the compositional evolution of the Earth in time and space in relation to the plate tectonic cycle. This includes determining mass exchange rates of chemicals between the various reservoirs of the Earth, such as the atmosphere, the ocean, the continental and oceanic crust, the mantle, and the core, as well as determining their residence times and the mixing scales involved. The development of new experimental techniques is also an issue of ongoing interest. VGP overlaps strongly with other Sections, such as Planetary Sciences, Tectonophysics, Seismology, Geomagnetism and Paleomagnetism, and Hydrology.