Intermonsoonal equatorial jets

Abstract

Three transects each from the cruises of RV Pioneer (84-degrees, 88-degrees and 92-degrees-E) during May-June 1964 and RV Vityaz (77-degrees, 84-degrees and 94-degrees-E) during October-November 1962 were used to compare pre and postmonsoon equatorial jets, respectively. Hydrographic features and transport computations favour a well developed equatorial jet during both seasons. The net surface eastward and subsurface westward flows are well balanced during the premonsoon transition period and appear to be decreasing from 84-degrees to 92-degrees-E. In general, equatorial jet seems to be at its peak at 84-degrees-E irrespective of the season. Proximity of two opposing currents found one below the other during premonsoon within the equatorial jet would induce mixing, which may account for the vanishing of high salinity core that is otherwise associated with any eastward flow, and the formation of a layer of homogeneous water at the equator. Absence of similar phenomena, as in the case of postmonsoon transition, may preserve the structure of high salinity core.