On the relative (Geostrophic) currents in the south eastern Arabian Sea

Abstract

Determination of space distribution of ocean currents in the sea is one of the most important problems in dynamical oceanography. Such studies facilitate the determination of the areas of convergence and divergence in the ocean, which are of important consequence to the fertility and thus to the fisheries of the region (Hela and Laevastu, 1961). Studies regarding current patterns along the west coast of India from hydrographical observations have been made by the Central Marine Fisheries Research Institute, from the data collected on board the research vessels VARUNA and, KALAVA (Sastry, 1959 ; Ramamirtham etal, 1960 ; Jayaramane/ al.,1960 ; Patil et al., 1963). The above-mentioned accounts pertained to a coastal belt of maximum width 150 miles only, and for localised areas around the Laccadives. Moreover, in all these studies the main properties considered for the current studies were temperature and Sigma-T only, as the data collected were not sufficient to permit a detailed study using the method of dynamic computation. During the period November 1962 - January 1963 detailed hydrographic studies were made in the southeastern Arabian Sea, covering a vast region between 11° and 17° N, within the meridians of 70° and 75° E. The observations were extended to deeper waters of 2000-3000 m., and the whole region was covered within a period of nearly one and a half months. Hence it was considered worthwhile to attempt a detailed study of the current patterns from the geopotential topographies of the isobaric surfaces, and the data collected were quite sufficient for the purpose.