Caribbean precipitation: review, model and prospect

Abstract

The study of Caribbean climate pre-1990 focused almost exclusively on attempts to link spatial patterns in climatic variables to physical processes. Much of this research assumed a `simple' regional climate, warm year round with a wet season dominated by tropical cyclones, but researchers soon found that a precipitation regionalization of the Caribbean was not as straightforward and simple. Consequently, a satisfactory understanding of the regional precipitation climate has eluded researchers for much of the second half of the twentieth century. Recently, with the increased availability and quality of satellite and precipitation data, researchers have begun to use gridded data sets to identify the spatial boundaries of the bimodal precipitation region and the atmospheric processes associated with the two maxima and minimum in precipitation. The findings of these most recent studies can be combined to construct a five part (North Atlantic high pressure, low level Caribbean jet, subsidence caused by Central America convection, basin wide increased wind shear, and divergence around Jamaica) conceptual Caribbean precipitation model that begins to address spatial variability in the bimodal structure of annual rainfall and the development of the midsummer minimum in precipitation. Such a regional precipitation climate model provides hypotheses to be tested and investigated in future research. Further, researchers must work towards a more effective and clear communication of the bimodal nature of Caribbean precipitation and the associated summer decrease in precipitation, integrate upper air analysis into the current working hypotheses, and further examine the interannual to interdecadal variability of the Caribbean midsummer drought for prediction purposes.