Monday, 23 January 2012: 2:15 PM
Precipitation Changes near Three Gorges Dam, China: Can TRMM or GPM Data Help with the Analysis
Room 257 (New Orleans Convention Center )
In October 2010, the water level upstream of the Three Gorges Dam (TGD) reached the designated 175 m. The associated inundation and land use/land cover changes have important implications for water resource management, agriculture, ecosystems, and the hydroclimate. This study examines the impact of TGD on regional precipitation using NASA Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis (TMPA) data from 1998 to 2009. The study area is divided into two sub-regions based on empirical orthogonal functions. Then satellite estimates are verified with rain gauges annually and seasonally for all study regions. Spatially, the point source gauge data is gridded using Thiessen Polygons for comparison with satellite data. The results yield strong statistical support for applying satellite rainfall data for hydroclimate studies in this region. Monthly epoch analyses ("pre-dam", "post-dam" and "post-dam II") are performed. Composite analyses on heavy rain days (top quartile) and moderate rain days (mid 50 percentile) revealed that heavy rain composites do not show major distinguishable changes. However, in the two “Post Dam” epochs, moderate precipitation is greatly reduced in the vicinity of the reservoir, while enhanced on both sides of the reservoir. Overall, this analysis presents one of the most thorough and long-term analyses of TGD-hydroclimate relationships to date.