Project Funding: 2008 - 2011

NRA: 2007 NASA: Carbon Cycle Science   

Funded by NASA

Abstract:
Northern Eurasian lakes and wetlands are the source of over ten percent of global methane emissions, but the uncertainty may be as large as a factor of three, and the sensitivity of these fluxes to rapid ongoing warming in the region is not well known. We propose to assess the effects of changes in lake and wetland extent and accompanying thermal variations associated with ongoing climate change, as well as permafrost degradation, on Northern Eurasia's net CO2 and methane emissions, both retrospectively (last half-century) and over the next century. The large uncertainties in estimates of CO2 and methane emissions in the region are mostly attributable to the sparseness of ground observations. We will, therefore, focus on development and extension of CO2 and methane emissions models coupled with representations of key hydrological and thermal drivers, which will be tested at limited existing in situ observation sites, and driven with remote sensing data that will help to characterize the key driving properties, such as extent of inundation. We will then use remote sensing data of lake and wetland extent and their temporal variations to help constrain model estimates of regional scale fluxes. A major thrust of our work will be to create a time series of satellite imagery that will provide accurate estimates of the temporal evolution of the extents and net methane and CO2 emissions of lakes and wetlands. For the measurement of lake and wetland spatial extent, our strategy will be to use high-resolution, long-repeat-cycle SAR imagery to calibrate a low-resolution, fast-repeat cycle time series from AMSR-E and MODIS. The high-resolution element of our strategy will be ALOS/PALSAR-derived classification of lake and wetland extent acquired in 2006-2007 and future years over focused study regions and comparison with JERS -derived products acquired in 1998 or earlier over the same region. The lower-resolution time series component will be based on analysis of wetland dynamics derived from AMSR-E from 2002 onwards. We will extend information extracted from remote sensing data through use of our large-scale, process-based Variable Infiltration Capacity (VIC) model, which we will continue to enhance to represent methane and CO2 fluxes from lakes as well as wetlands over a region where in situ data are sparse. The enhanced VIC framework will allow estimation of the spatial distribution of water table position and the dynamics of lakes and seasonally-inundated wetlands. Using this modeling framework, we will reconstruct the evolution of the region's lake and wetland extent over the last halfcentury, and perform multimodel ensemble simulations using statistically downscaled IPCC AR4 model output for the next century. Finally, we will identify the major uncertainties in the carbon budgets of Northern Eurasia's lakes and wetlands, and determine where future remote sensing (and/or ground data collection) efforts might be focused to most effectively reduce these uncertainties. This work addresses NASA's Strategic Goal 3A.3, which is to quantify global land cover change and terrestrial and marine productivity, and improve carbon cycle and ecosystem models. More specifically, this proposal contributes directly to the goals and objectives of The Northern Eurasia Earth Science Partnership Initiative (NEESPI).

2011 NASA Carbon Cycle & Ecosystems Joint Science Workshop Poster(s)

• Satellite Remote Sensing of Inundated Wetlands: Global Data Record Assembly Status and Development Plans   --   (Kyle McDonald, Bruce Chapman, Erika Podest, Ronny Schroder, Laura L. Hess, Lucas A Jones, John S Kimball, Mahta Moghaddam, Jane Whitcomb)   [abstract]

2008 NASA Carbon Cycle & Ecosystems Joint Science Workshop Posters

• An Inundated Wetlands Earth System Data Record: Global Monitoring of Wetland Extent and Dynamics   --   (Kyle C. McDonald, Bruce Chapman, Laura Hess, Mahta Moghaddam, Elaine Matthews, John S. Kimball, Catherine Prigent)   [abstract]
• Radar Remote Sensing of Wetlands in Boreal Eurasia and North America for use in Methane Emission Modeling   --   (Erika Podest, Kyle McDonald, Ted Bohn, Dennis Lettenmaier, Mahta Moghaddam, Jane Whitcomb)   [abstract]   [poster]