CR prepress abstract  -  DOI:

Inter-annual variability of moisture transport over the northern Indian Ocean and South Asian Summer Monsoon

F. S. Syed, A. Hannachi


ABSTRACT: The inter-annual variability of the vertically integrated zonal / meridional moisture transport in the lower troposphere, over the northern Indian Ocean is studied. Observed data from 1971 to 2016 for the South Asian Summer Monsoon (SASM) season is used. The moisture transport variability is dominated by the zonal component associated with Somali low level jet. For the identification of dominant modes of inter-annual variability, three dimensional empirical orthogonal function analysis is performed. The leading mode associated with suppressed meridional moisture transport in both Arabian Sea and Bay of Bengal and increased zonal moisture transport over the Bay of Bengal is linked with the positive phase of Indian Ocean dipole and El-Nino conditions in the Pacific Ocean. Whereas second leading mode is associated with the enhanced zonal moisture flow over the Arabian Sea extending up to the Bay of Bengal allied with Somali low level jet, and enhanced northeastward moisture transport over the whole region. This enhanced moisture flow results in stronger monsoon circulation and increased rainfall over South-Asia.