ASSESSING VARIABILITY IN SUDD WETLANDS FROM GRACE AND MODIS: 2003-2013

The Sudd Marshlands, located in Sudan, is one of Earth’s most expansive wetlands, covering an average area of over 30,000 km². This area has the potential to change greatly due to below or above-average rainfall events. East Africa has two rainy seasons called the "short rains" (October to December) and the "long rains" (March to May). The short rains are important because they serve to refuel the water supply of the marshes. Variability in Indian ocean temperature differentials, described by the Indian Ocean Dipole (IOD), is a major driving factor of rainfall variability in East Africa. When the sea surface temperature (SST) anomalies are warmer toward the eastern/central Indian Ocean, East Africa gets more rain than usual. Cold eastern SST anomalies result in a drier season for East Africa. We measure monthly variability of total water storage in the Sudd system over the past ten years using time-varying GRACE measurements. For the same period, we determine time varying (monthly) open water extent and extent of wetlands cover using MNDWI and NVDI derived from MODIS satellite imagry. These data are analyzed to determine changes in the Sudd extent over the past ten years, correlation between IOD anomalies, Sudd water storage anomalies and Marshlands extent.