Relationship between sea surface temperature, southern oscillation, position of the 500 mb ridge along 75ºE in April and the Indian monsoon rainfall

Abstract

Relationships between the seasonal sea surface temperature values of four oceanic regions, namely the western Arabian Sea, the eastern Arabian Sea, the Bay of Bengal and the sea off Somalia coast with the Southern Oscillation Index, position of the 500 mb ridge along 75ºE in April and the summer monsoon rainfall for the period 1948 to 1972 are studied. There is positive and significant relationship between the preceding winter sea surface temperatures in the Bay of Bengal and the 500 mb ridge position along 75ºE in April. The study further shows that sea surface temperature anomalies in the Arabian Sea and the north Indian Ocean during the summer monsoon are caused by the monsoon circulation/monsoon activity over India rather than vice versa. It was also found that the premonsoon sea surface temperature values in three of the above study areas are useful for predicting the monsoon rainfall.