Monsoon variability in relation to equatorial trough activity over Indian and West Pacific Oceans

Abstract

Variability of Indian monsoon rainfall has been examined in relation to the convective activity of the equatorial trough over the Indian Ocean a~d the Pacific Qcean west of the International Date Line. It is found that the cyclogenesis (tropical cyclones) near the West Pacific equatorial trough is closely related to this variability through a see-saw in. convection between this ocean basin and north Indian Ocean, with period in the range 30-50 days. SST anomalies over north Indian Ocean and West Pacific Ocean can cause variability of the date of onset of monsoon and also the quantum of monsoon rainfall over India through the 30-50 day mode.