Influence of eastern Arabian Sea on summer monsoon rainfall over west coast of India

Abstract

Sea surface temperature (SST) anomalies have been assigned as one of the boundary conditions in the global circulation models for simulation of climatic changes. The effects of SST anomalies on the summer monsoon simulations are both of local and distant nature. In order to realise the model results and the influence of Arabian sea in the context of long range forecasting of monsoon rainfall, we have examined the correlation between the rainfall over west coast of India and premonsoon thermal anomaly field in the eastern Arabian Sea where larger atmospheric convection as compared to that over other parts of the water body normally takes place during the summer monsoon season. The present results based on observations during ten years' period (1975-1984) have not shown local influence (higher SSTs causing higher rainfall) of the sea. On the contrary, a negative association has been observed in the sense that monsoon activity at west coast of India is more likely to be less when abnormal pre-monsoonal warming takes place in the eastern Arabian Sea