Formation mechanisms of temperature inversions in the Southeastern Arabian Sea

Abstract

Numerical simulations using a high resolution (0.25°×0.25°, 40 levels) OGCM of the Indian Ocean are used to study the formation mechanisms of temperature inversions (TI) in the southeastern Arabian Sea (SEAS) during winter. To the west and south of India, haline stratification is a necessary pre-requisite for TI formation. Off the southern tip of India, low-salinity water advected from the Bay of Bengal is cooled by strong winds and leads to TI formation. In the southern part of the SEAS, advection of this cooler low-salinity water over warm salty SEAS water leads to the formation of TI and occur at a deeper depth (~80 m) due to the downwelling within the Lakshadweep High. In the northern part, TI occur at a much shallower depth (~20 m) and are caused by shortwave radiation penetrating below the mixed layer of about 12 m.