Assessing Links Between Water and Carbon Storage in Indonesian Peatlands Using Data from the Gravity Recovery and Climate Experiment

Wednesday, 17 December 2014: 3:25 PM
Erin Swails1, John T Reager2, James Tremper Randerson3, James S Famiglietti3, Deborah Lawrence1 and Kailiang Yu1, (1)University of Virginia Main Campus, Charlottesville, VA, United States, (2)NASA Jet Propulsion Laboratory, Pasadena, CA, United States, (3)University of California Irvine, Irvine, CA, United States
Deforestation and drainage of tropical peat swamp forests for conversion to other uses results in a loss of carbon storage through the clearing and burning of forest vegetation as well as decomposition of peat soils and increased frequency of fires following drainage. We used Gravity Recovery and Climate Experiment (GRACE) terrestrial water storage observations and a global forest cover change product to investigate trends in terrestrial water storage associated with land use conversion in Indonesian peatlands between 2002 and 2012. Our initial analysis indicated that secular trends in GRACE terrestrial water storage were consistent with the spatial distribution of peatlands drained for the establishment of oil palm plantations. A decreasing trend in GRACE terrestrial water storage measurements over the observation period indicated a substantial decrease in water table heights. Combining this information with measurements of bulk density and carbon content of surface peat layers, we estimated potential emissions from carbon stocks now vulnerable to oxidation. Independent measurements of fire carbon emissions were used to estimate the fraction of committed emission that was combusted. Our research represents the first known application of GRACE data to assess loss of soil carbon storage associated with depletion of soil water.