HR: 1340h
AN: GC23A-1303    [Abstracts]
TI: Vegetation Variability And Its Effect On Monsoon Rainfall Over South East Asia: Observational and Modeling Results
AU: Sarkar, S
EM: ssarkar@forestone.com
AF: Forest One Inc, 300 Park Blvd., Suite 425, Itasca, IL 60143 United States
AU: Peters-Lidard, C
EM: Christa.Peters@nasa.gov
AF: Hydrological Sciences Branch, GSFC, GSFC, NASA, Greenbelt, MD 20771 United States
AU: * Chiu, L
EM: lchiu@gmu.edu
AF: School of Computational Science, George Mason University, 4400 University Blvd, Fairfax, VA 22030 United States
AU: Kafatos, M
EM: mkafatos@gmu.edu
AF: School of Computational Science, George Mason University, 4400 University Blvd, Fairfax, VA 22030 United States
AB: Increasing population and urbanization have created stress on developing nations. The quickly shifting patterns of vegetation change in different parts of the world have given rise to the pertinent question of feedback on the climate prevailing on local to regional scales. It is now known with some certainty, that vegetation changes can affect the climate by influencing the heat and water balance. The hydrological cycle particularly is susceptible to changes in vegetation. The Monsoon rainfall forms a vital link in the hydrological cycle prevailing over South East Asia This work examines the variability of vegetation over South East Asia and assesses its impact on the monsoon rainfall. We explain the role of changing vegetation and show how this change has affected the heat and energy balance. We demonstrate the role of vegetation one season earlier in influencing rainfall intensity over specific areas in South East Asia and show the ramification of vegetation change on the summer rainfall behavior. The vegetation variability study specifically focuses on India and China, two of the largest and most populous nations. We have done an assessment to find out the key meteorological and human induced parameters affecting vegetation over the study area through a spatial analysis of monthly NDVI values. This study highlights the role of monsoon rainfall, regional climate dynamics and large scale human induced pollution to be the crucial factors governing the vegetation and vegetation distribution. The vegetation is seen to follow distinct spatial patterns that have been found to be crucial in its eventual impact on monsoon rainfall. We have carried out a series of sensitivity experiments using a land surface hydrologic modeling scheme. The vital energy and water balance parameters are identified and the daily climatological cycles are examined for possible change in behavior for different boundary conditions. It is found that the change from native deciduous forest vegetation to crop land affects monsoon rainfall in two ways: 1) The presence of cropland increases the sensible heat release from ground, increasing the chances for development of forced convection; 2) Large scale irrigation associated with spring crop development creates a moister lower boundary layer thus inducing more moist instability and free convection in the succeeding season.
DE: 0480 Remote sensing
DE: 1631 Land/atmosphere interactions (1218, 1843, 3322)
DE: 1632 Land cover change
DE: 1834 Human impacts
DE: 1854 Precipitation (3354)
SC: Global Climate Change [GC]
MN: Fall Meeting 2005