During the past 150 years, the Southern Bottomlands across the alluvial flood plains in Tennessee, Arkansas, Mississippi and Louisiana, along the Mississippi River, have been gradually converted to agricultural and other anthropogenic use, especially during the years 1880 to 1960. This region is referred to as the Lower Mississippi Alluvial Valley (LMAV). The main purpose of this research is to attempt to relate the current and historical land use and land cover in the LMAV to near surface temperature patterns, trends, and return values of the temperature extremes.

Land use change patterns for the Mississippi Delta region for the last several decades are being compiled based on information from forest and agriculture surveys, satellite imagery analysis and the MODIS derived land use patterns for the present. Historical records of surface meteorological observations from the U.S. Historical climatology Network (USHCN), over areas that experienced the most significant changes in land use, are being examined to determine if there are trends in surface temperature, dew point, precipitation and cloudiness that could be related to changes in land use. Our initial focus is on the analysis of monthly surface temperatures. The monthly surface temperature observations have been corrected to detect and account for undocumented change points as well as for missing data. The historical trends for the monthly mean minimum and maximum temperatures have been computed. The results are being analyzed to compare the trends of with in the LMAV to the trends in the surrounding regions. The return levels of the extreme values of the temperature ranges are also being computed, and will be compared across the landscape domains. This observational study is expected to complement a parallel numerical modeling analysis, and together they are expected to enhance our understanding of the complexity and implications of the meteorological impacts of the conversion of forests and wooded areas for anthropogenic use. The conversion of forests to agricultural use is expected to change the minimum and maximum temperature, and hence the diurnal temperature range and their trends.