IMPACT OF INCREASED CO_(2) ON RAINFALL OVER INDIAN MONSOON REGION IN IPCC-AR4 CGCM SIMULATIONS

摘要

An attempt is made to study the spatial and temporal changes in meteorological parameters that are likely to take place over the Indian monsoon region when CO_(2) doubles from the present level. We use the most comprehensive multi-model perspectives of climate changes as of today generated as part of IPCC-AR4, archived at the Program for Climate Change Model Diagnosis and Inter comparison (PCMDI) at the Lawrence Livermore National Laboratory, USA for this purpose. We selected 6 out of 15 models for the CO_(2) doubling studies that produce the annual cycle of rainfall over the Indian summer monsoon region reasonably well in the 20th century experiments. The CO_(2) doubling simulations by these 6 models suggest that the rainfall rate over the India monsoon region is likely to increase during the entire year except the spring season. During summer monsoon season, peak rainfall increase (>3 mm day~(-1)) is seen over the head Bay of Bengal and adjacent regions.