MONSOON RAINFALL AND SOUTHERN OSCILLATION RESPONSES IN THE PRESSURES OVER THE NORTHERN INDIAN OCEAN

The pressure variations over the North Indian Ocean during the summer monsoon season have been exam-ined using the monthly data from June to September for the period 1961 to 1968. It is found that these varia-tions can be described by two significant eigenvectors (EV1 and EV2) which together account for 53% of the total variance.The first eigenvector (EV1) represents in phase variation over both, the Arabian Sea and the Bay of Bengal with higher variations over the northern side of the area. The second eigenvector (EV2) depicts the out-of-phase variation between the pressure anomalies over the north and the south of 15°N latitude with two areas of pronounced variation, viz., the head Bay of Bengal and the equatorial region near 65°E longitude.The coefficients of EV1 show significant association with rainfall of West Coast and Central India for the concurrent months. These coefficients also show significant association with the pressure and temperature indices of the Southern Oscillation. The coefficients of EV2 show significant association with the monsoon rainfall of south peninsular India.