Journal of Oceanography, Vol. 63 (No. 1), pp. 1-14, 2007
Mohammed Ali Al Saafani1* and S. Satheesh Chandra Shenoi2
1Department of Earth Science and Environment, Faculty of Science, Sana'a University, Sana'a, Yemen
2National Institute of Oceanography, Goa - 403 004, India
(Received 26 January 2006; in revised form 3 July 2006; accepted 31 July 2006)
Abstract: Hydrographic data collected from Gulf of Aden since 1920 have been compiled to identify and refine the definitions of water masses in the Gulf of Aden (GA) and to describe their spatio-temporal variability. Four water masses have been identified based on their &theta-S characteristics. The Red Sea Water (RSW) that flows from the Red Sea is the most prominent water in the GA; this occupies about 37% of the total volume of Gulf of Aden. The Gulf of Aden Surface Water (~3%) forms as a mixture of local water and the water from western Arabian Sea during winter and Red Sea surface water during summer. The intermediate water, identified as Gulf of Aden Intermediate Water (GAIW), occupies about 9% of the total volume of GA; a characteristic salinity minimum is associated with it at σθ = 26.50 kg m-3. The northward spread of sub-tropical subsurface water from the south appears to be the major source of GAIW. The bottom water, named Gulf of Aden Bottom Water, showed the least variability. It was formed due to the mixing of Red Sea Water and water of southern origin. Mixing triangles have been used to analyze the composition of water in the GA.