ASSESING WATER FLUXES IN REGIONAL WETLANDS WITH MODIS AND GRACE

Large regional wetlands systems, such as the Iraqi (Mesopotamian) Marshes, an extensive wetlands system in Iraq, and the Sudd Marshlands, located in Sudan, the Panatal, across Brazil, Bolivia and Paraguay have been heavily impacted by either or both of human and climate forces over the past decades. The Sudd wetlands are highly variable in size, averaging roughly 30,000 km², but extending to as large as ~130,000 km² during the wet seasons. The Iraqi marshes are smaller, at ~15,000 km², without the same extent of intra-annual variability. The Panatal are the worlds largest wetlands, with size estimates of between 140,000 and 210,000 km². Using a combination of MODIS and GRACE images from 2003-2015 for these three areas, we determined the time dependent change in surface water area (SWA) in the marshes, marshland extent and variability in total water storage. We related the SWA and vegetation abundance and cover, as determined by MODIS (NDVI and MNDWI), and found it to be correlated with total mass variability observed by GRACE (RL05 Tellus land grid). Annual variability in the Iraqi marshes correlates well with combined SWA and vegetation extent. Variability of vegetation in the Sudd marshes is seen to correlate well on an annual basis with water storage variation, and with a 2 month lag (water mass increases and decreases lead vegetation increases and decreases) when examined on a monthly basis. Despite the relative abundance of water in these systems. The overall wetlands extent and health in these systems is observed to be water limited.