Water Resources Research Act Program

Principal Investigators: Vasubandhu Misra, Henry Smith

Abstract: The research objective of this proposal is to discern the regional climate variations of the Caribbean Islands as a result of the large-scale interannual variations associated with the Atlantic Warm Pool (AWP). The Atlantic warm pool that peaks in the August-September-October season varies in its size appreciably from year to year, decade to decade and has a background linear trend as well. Given these large-scale variations of the AWP that is also associated with changes in the strength of the trades in the Atlantic Ocean and the Caribbean low level jet, it is important to realize their influence on the regional climate variations of the relatively smaller Caribbean islands. A very high resolution Regional Climate Model (RCM) integration at 5km horizontal resolution forced with the National Centers for Environmental Prediction & National Center for Atmospheric Research (NCEP-NCAR) reanalysis is proposed to diagnose the influence of the AWP variations on the corresponding seasonal-interannual variations of the Caribbean rainfall. The high resolution is necessary to resolve some of the smaller islands (including the U.S. Virgin Islands) and the local orography therein. It is anticipated that this high-resolution study will also enable us to examine the diurnal variations of the rainfall in these islands and the frequency of the extreme events like tropical storms in the August-September-October season. Since the pattern of the AWP variations across many temporal scales are similar, the conclusions of this study on the Caribbean rainfall variability could possibly be also used in understanding the influence of the AWP variations at longer time scales.