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Remote Sensing of Global Wetland DynamicsAlthough natural wetlands only cover about 4% of the earth's ice-free land surface, they are the world's largest methane (CH4) source and the only one dominated by climate. In addition, wetlands affect climate by modulating temperatures and heat fluxes, storing water, increasing evaporation, and altering the seasonality of runoff and river discharge to the oceans. Current CH4 emissions from wetlands are relatively well understood but the sensitivity of wetlands and their emissions to climate variations remains the largest uncertainty in the global CH4 cycle and could strongly influence predictions of future climate. Therefore, characterizing climate-sensitive processes prevailing in the world's wetlands is crucial to understanding and predicting physical and biogeochemical responses of wetlands to interannual and longer-term climate variations. Recent research has resulted in the first generation of models to predict methane emissions from wetlands but the models must still be applied to static data on wetland distributions. Moreover, no models currently exist to realistically predict the distribution and dynamics of wetlands themselves for the current, or any other, climate. The dominant obstacle to modeling wetland dynamics has been lack of remote sensing techniques and data useful for characterizing quantitatively the seasonal and interannual variations of wetlands. We report on initial remote sensing studies undertaken to validate a global hydrological model linking rivers, takes and wetlands. Using a combination of SSM/I microwave and TOPEX Poseidon altimetry data sets, we developed and applied techniques to quantify inundation extent and duration for several large wetlands in tropical Africa and South America. Our initial results indicate that seasonally-inundated wetlands can be well characterized over large spatial scales and at monthly time scales using these remote sensing data. The results also confirm that currently available remote sensing products can be applied to provide crucial data to the research community modeling global hydrological and biogeochemical cycles.
Document ID
20000095577
Acquisition Source
Goddard Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
Matthews, Elaine
(NASA Goddard Inst. for Space Studies New York, NY United States)
Prigent, Catherine
(NASA Goddard Inst. for Space Studies New York, NY United States)
Birkett, Charon
(Universities Space Research Association Greenbelt, MD United States)
Coe, Mike
(Wisconsin Univ. Madison, WI United States)
Hasen, James E.
Date Acquired
August 19, 2013
Publication Date
January 1, 2000
Subject Category
Earth Resources And Remote Sensing
Meeting Information
Meeting: Remote Sensing of Environment
Location: Cape Town
Country: South Africa
Start Date: March 27, 2000
End Date: March 31, 2000
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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