Summer cooling of the Arabian Sea during contrasting monsoons

Abstract

Temperature and salinity profiles from the upper ocean in the Arabian Sea, measured by Argo floats, together with satellite derived sea surface temperature and winds are used to examine the response of the Arabian Sea to the contrasting monsoons of 2002 and 2003. The Indian summer monsoon rainfall of 2002 was unusually low compared to a near normal monsoon during 2003. Contrary to the general belief that a stronger Indian summer monsoon causes larger summer cooling and leaves behind a cooler Arabian Sea, we find that the Arabian Sea was warmer during 2003 summer than during 2002. The delayed onset of the summer monsoon during 2003 led to this difference. Although the winds during 2003 July were stronger it was not able to compensate for the weak and delayed onset of southwesterlies during 2003. This implies that a strong summer monsoon over India does not necessary imply a larger thermodynamic impact on the Arabian Sea. The strength and duration of the southwesterlies are the decisive parameters for the summer cooling of the Arabian Sea.