88th Annual Meeting (20-24 January 2008)

Wednesday, 23 January 2008: 11:00 AM
Numerical model simulations of regional weather and climate impacts due to changes in historical landuse in lower Mississippi river valley
224 (Ernest N. Morial Convention Center)
Valentine Anantharaj, Mississippi State University, Starkville, MS; and U. S. Nair, A. Song, L. Wasson, S. Christopher, P. J. Fitzpatrick, and R. King
The Lower Mississippi Alluvial Valley (LMAV) (also known as the Mississippi Delta) is an area subject to significant changes in land use during the past 150 years. Since the mid 1800s, the bottomland hardwood forests in the rich alluvial valley across Arkansas and Mississippi have been gradually converted into agricultural croplands. The extent of land use change in the Mississippi Delta region is obvious in the satellite imagery, which reveal the existence of a sharp boundary, especially along in the eastern region of the lower Mississippi river valley. Historical landuse maps for this region have been created using agricultural and forest surveys. A numerical mesoscale model is being used to analyze potential changes of atmospheric circulation, precipitation and cloud formation for pristine and anthropogenic altered land use scenarios.

In order to incorporate the historical land cover information into the numerical model, the land use maps have been complemented further with satellite imagery analysis and the MODIS derived land use patterns for the present. Numerical model experiments are being conducted using the Regional Atmospheric Modeling System (RAMS). The MODIS observed seasonal variations of vegetation characteristics, such as albedo, emmisivity, vegetation fraction and Leaf Area Index (LAI) over the study area, are also being utilized in the simulations. Detailed, higher spatial resolution simulations will be used to study differences in cloud formation over adjacent areas of contrasting land use, such as in the vicinity of the sharp border region in the eastern Mississippi region between agricultural and forested areas. Observational and numerical modeling analyses are expected to provide understanding of the processes through which land use change impact the regional climate of this region, allowing for interpolation of the results to other areas in the southeast.

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