Significant Decrease In Rainfall Research Articles

IMPACT OF CHANGES IN LAND SURFACE PARAMETERS ON PRECIPITATION OVER INDOCHINA USING A GCM

Simplified deforestation effects on the climate over Indochina is assessed usinga GCM. In the simulation, a significant decrease in rainfall over Indochina is found in April and May (the beginning of the wet season) as a result of the simplified deforestation. On the contrary, no significant decrease is found in the time series of observed rainfall data in April and May. As the strong sensible heat calculated at forested land surface in Indochina in the dry season is supposedto be inadequate, additional two sets of numerical experiments are carried out with simple modifications to the land surface scheme. However, the decrease in rainfall is still found in the results of the numerical experiments. Change in Bowen ratio doesn't seem to play a major role within “land surface-rainfalrlelationship.”

A Comparative Study of the Effects of Albedo Change on Drought in Semi–Arid Regions

Numerical simulation studies of the effects of changes in albedo on rainfall involve comparisons of semiarid areas, lying at the boundary between a major desert and an adjacent monsoonal region, with areas of the same size located within the monsoonal region itself. The sensitivity of the rainfall to the ground hydrology was determined by performing the albedo simulations with two different evapotranspiration parameterizations, one giving too high evaporation over land and the other giving negligible evaporation over land. The evaporation rate is, in general, found to have as important an effect as changes in albedo. The mechanism by which an increase of albedo reduces the rainfall during conditions of high evaporation is considered.