A diagnostic analysis of MONEX-1979 onset vortex over the Arabian Sea

Abstract

Based on MONEX-,1979 data over the Arabian Sea, the paper analyses observationally the structure, development and movement of a vortex which formed during onset of the monsoon around mid-June near the coast of Kerala developed into a cyclonic storm at mid-sea and moved towards the coast of Oman to die out there Heat budget computations bring out the differential behaviour of the different quadrants of the disturbance and appear to highlight the contrasting features between the northwestern and the other quadrants in regard to vertical. distributions of diabatic heating, local temperature tendency thermal advection and adiabatic heating or cooling. The study reveals an interaction of the vortex with two eastward-propagating subtropical westerly troughs which might have contributed significantly to its explosive development (decay) through warm (cold) advection. Both barotropic and baroclinic energy conversions appear to supply energy to the storm; though there appears to be a dominance of one over the other at different stages of development and at different heights. It seems likely that condensation heating also contributed to development of the storm.