Research in Earth System Science

ESSIC is a joint center between the University of Maryland Departments of Meteorology, Geology, and Geography together with the Earth Sciences Directorate at the NASA/Goddard Space Flight Center. ESSIC also administers the Cooperative Institute for Climate Studies (CICS) which is joint with NOAA’s National Centers for Environmental Prediction (NCEP) and the National Environmental Satellite and Data Information Service (NESDIS). The goal of ESSIC is to enhance our understanding of how the atmosphere-ocean-land-biosphere components of the Earth interact as a coupled system and the influence of human activities on this system. This is accomplished via studies of the interaction between the physical climate system (e.g., El Nino) and biogeochemical cycles (e.g., greenhouse gases, changes in land use and cover). The major research thrusts of the center are studies of Climate Variability and Change, Atmospheric Composition and Processes, the Global Carbon Cycle (including Terrestrial and Marine Ecosystems/Land Use/Cover Change), and the Global Water Cycle. The manner in which this research is accomplished is via analyses of in situ and remotely sensed observations together with component and coupled ocean-atmosphere-land models. Together this provides a foundation for understanding and forecasting changes in the global environment and regional implications. Data assimilation and regional downscaling provide the means by which the observations and models are linked to study the interactions between the physical climate system and biogeochemical cycles from global to regional scales.
Contact : Prof. Antonio Busalacchi (tonyb@essic.umd.edu, phone 301-405-5599)

Climate Variability and Change
Societies around the world have developed on the expectation of a stable climate with the regular rotation of seasons. Climatic events such as the El Nino/Southern Oscillation (ENSO) that disrupt the normal seasonal cycle have heightened awareness that in reality, climate can vary dramatically from year to year and these variations can have significant impact on society. Research in the past 10-20 years has demonstrated that ENSO is an intrinsic oscillation of the coupled ocean-atmosphere system. Climate also demonstrates long period and more sustained variability that are less well understood: the changes in annual rainfall in the African Sahel on decadal and longer time-scales, sustained periods of droughts in the Nordeste of Brazil, and the dust bowl years of the 1930s in the United States are examples of longer-term variations in climate. The rise in atmospheric concentration of greenhouse gases and the predictions of global warming and regional climate change in the future is yet another example. Taken together these examples of climate variability and change represent a need to understand better the coupled climate system, its natural variability, and potential modifications by anthropogenic causes such as the increase of radiatively active gases and changes in atmospheric aerosol loading.

The goals of ESSIC research are oriented towards improving our understanding, monitoring and predictive capability of the physical processes responsible for climate variability and predictability on seasonal, interannual, decadal, and centennial time-scales. Key components of the research strategy include:

• focus on the role of the coupled ocean and atmosphere within the overall climate system, with emphasis on variability, especially within the oceans, on seasonal to centennial time scales.
• development of data assimilation methods to merge remotely sensed and in situ observations with models of the climate system
• development and application of regional and global models of the coupled climate system
• analysis of remotely-sensed, instrumental and quality-controlled paleoclimatic data sets
• study of the response of the climate system to increases of radiatively active gases and aerosols as well as changes in land surface
• exploration of predictability and how to improve predictions of climate variability and climate change using existing, re-analysed, and new global observations, enhanced coupled ocean-atmosphere-land-ice-ecosystem models, and paleoclimate records.

Atmospheric Composition and Processes
The atmosphere links the components of the Earth System, including the oceans, geosphere, terrestrial and marine biospheres, and cryosphere. As a result, the atmosphere is the conduit for change be it local or via remote teleconnections on a global scale. For example, natural events and human activities can change atmospheric composition and hence the Earth's radiative balance. Subsequent responses by the climate system and the stratospheric ozone layer can influence not only natural systems, but the biosphere as well. In addition, the atmosphere represents the fast response of the coupled Earth System. In view of the rapid and often-global dispersal of chemical emissions, observations of changes in the atmosphere are among the very earliest indicators of global changes.

The goals of ESSIC research are oriented towards improving our understanding, monitoring and predictive capability of the interrelationships of changes in atmospheric composition, climate, ozone-layer depletion, and surface-level chemical and radiative exposure. Key questions involving Earth System interactions include:

• How do atmospheric composition changes alter the radiation balance of the climate system (and vice versa)?
• What are the interactions between the climate system and ozone layer?
• What are the effects of regional pollution on the global atmosphere and the effects of global climate and chemical change on regional air quality?
• How can human activities and natural ecosystems impact and be impacted by changes in atmospheric composition through subsequent alteration of global and regional climate, ozone-layer/ultraviolet radiation, and pollutant exposure?

Global Carbon Cycle (Terrestrial and Marine Ecosystems/Land Use/Cover Change)
Recent scientific, resource management, and policy developments have intensified interest in the global carbon cycle. Carbon is important as the basis for the food and fiber that sustain human populations, as the primary energy source that fuels human economies, and as a major contributor to the planetary greenhouse effect and the potential for climate change. CO2 and CH4 concentrations have been increasing in the atmosphere and are now higher than they have been for over 400,000 years. Human use of fossil fuels and land clearing over the past 150 years are the source for most of this increase. Changes in land management practices and CO2 and nutrient additions can also significantly enhance carbon sinks.

The goals of ESSIC research are oriented towards improving our understanding, monitoring and predictive capability of the global carbon cycle including the role and variability of terrestrial and marine ecosystems, land use, and land cover. Key questions involving Earth System interactions include:

• What are the dynamic storages, transfers, and pathways of carbon within the Earth system and how will this carbon cycling change in the future?
• What exchanges exist with the lithosphere on longer time scales?
• What are the primary controls on terrestrial and marine carbon sources and sinks ?
• What are the relative roles of processes in the ocean and on the land in determining the interannual growth rate in atmospheric CO2?
• What are the global patterns of land cover and use, and the role of land management practices on carbon storage and release?
• What are the interactions and feedbacks with the physical climate system induced by changes in terrestrial and marine ecosystems, land use, and land cover?

Global Water Cycle
The behavior of water in the Earth System is central to nearly every aspect of the global climate and crucial to human welfare. Interannual changes in precipitation and evaporation are associated with droughts and floods that threaten the lives and livelihood of millions of people. Evidence indicates that the global hydrological cycle is accelerating, resulting in an increasing number of extreme precipitation events. Improving our understanding of the ways that water influences, and is influenced by, the integrated Earth System is a critical component of our ongoing effort to predict climate variations and anticipate global climate change.

ESSIC’s research is oriented toward understanding, monitoring and predicting the global water cycle, including precipitation, evaporation, storage and transport, on time scales from weeks to centuries. Key questions involving Earth System interactions include:

• What are the dynamic pathways, storages, transfers and transformations of water within the Earth System, and how do they change in association with seasonal to interannual climate variability?
• What are the interactions and feedbacks between terrestrial and marine ecosystems, land use and land cover, and the global water cycle, and how will these evolve as atmospheric CO2 increases?
• How do regional changes in air pollution affect the local and global behavior of the water cycle?
• What is our ability to reproduce/assimilate, simulate and/or predict the water cycle and/or its components at global and regional scales using the state-of-the-art models and data assimilation systems?
• What new observations are needed to improve our understanding of the water cycle?
• How will the humidity of the stratosphere and upper troposphere change in response to anthropogenic CO2 emissions, and how will these changes influence other aspects of global change?

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