Water Resources Research Act Program

Details for Project ID 2009MS85B

Influences of Land Surface / Land Use Characteristics on Precipitation Patterns over the Lower Mississippi Alluvial Plain

Institute: Mississippi
Year Established: 2009 Start Date: 2009-03-01 End Date: 2010-11-30
Total Federal Funds: $11,104 Total Non-Federal Funds: $23,034

Principal Investigators: Jamie Dyer

Project Summary: The lower Mississippi River alluvial valley, within which is the Mississippi Delta, is extremely important for regional economic stability and growth due to the widespread agriculture in the area. Despite being in a sub-tropical climate, agricultural practices revolve around the use of irrigation to maintain crop production during the warm season. Research has shown that irrigation practices have dramatically reduced the levels of groundwater within the underlying aquifer, due in part to instances of drought over recent years where precipitation has been anomalously low. This shows the critical sensitivity of the region to precipitation variability, such that agricultural and hydrological systems may be substantially impacted by changes in rainfall patterns. To better prepare water resource managers, it is therefore necessary to understand the climatological mechanisms responsible for precipitation variability over the Mississippi Delta. This project will address this topic by analyzing high-resolution multi-sensor precipitation estimates from the National Weather Service (NWS) NEXRAD network over the lower Mississippi River alluvial valley. Initial results indicate that a definite pattern exists in which regional precipitation is minimized over the heavily irrigated Mississippi Delta with a corresponding maximum farther east along the Mississippi-Alabama border. It is hypothesized that land use / land cover characteristics may be augmenting existing climatological patterns, thereby intensifying the evaporation-precipitation cycle over the region while shifting it eastward. To better understand and identify the causes of the rainfall patterns, a sensitivity analysis will be performed using the Weather Research and Forecasting (WRF) model. The WRF model will provide information on the importance of various meteorological and surface conditions on convective initiation and precipitation over the region, providing information on the existence and/or extent of anthropogenic and climatological modification of rainfall patterns. This will lead to a better understanding of rainfall trends and patterns and potentially better prediction of future rainfall.