Indian Ocean moisture flux variations during summer monsoon and its relation with Indian rainfall

Abstract

1971-1977In this article, we discussed about the variations of moisture flux (MF) over the Indian Ocean (IO) and successive Indian summer monsoon rainfall (ISMR). MF calculated over 1000-850 mb levels at five different sub regions over the IO during 2006-2014. In monsoons months (June through September), moisture transported from the southern IO through Arabian Sea (AS) via a low-level jet produces rainfall in Indian subcontinent. MF commences in May then increases through August and then decreases by September. We verified the relation of five sub regions MF with ISMR and found northwest IO (NWIO), Arabian Sea (AS) have positive relation. However, the Bay of Bengal (BOB) and the central IO (CIO) indicated negative relation. Strong positive relation observed with correlation coefficients (CC) of 0.81 and 0.72 between MF and ISMR over NWIO and AS respectively, however BOB and CIO reveal an inverse relation (CC of –0.34 and -0.7). During an El Nino year, MF deviations are negative over the NWIO and AS, indicating lower moisture transport to India and consecutive ISMR is low. MF during El Nino/La Nina/normal monsoon season over the NWIO and AS areas are important for ISMR

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