A Statistical Study of the Relationships between Ocean Surface Temperatures and the Indian Monsoon

Abstract

The hypothesis that Indian Ocean sea surface temperatures are linked to the intensity of the Indian summer monsoon was tested using sea temperature, rainfall and sea level pressure data for the period 1949–72. The data sets were compacted using empirical orthogonal function analyses. The time coefficients of the most important functions were used to statistically test the general hypothesis. The results suggest that in summer a warmer Arabian Sea or Indian Ocean is weakly associated with decreased rainfall and increased sea level pressure over much of the Indian subcontinent. The relationship between the Indian summer monsoon and the sea surface temperatures of the eastern tropical Pacific Ocean was also investigated. This analysis suggests that higher than normal Indian sea level pressures are often associated with higher eastern Pacific sea temperatures one month later and higher Indian region sea temperatures another month later.