Heat and freshwater budgets in the Red Sea from direct observations at Bab el Mandeb

Direct oceanographic observations at the strait of Bab el Mandeb, which connects the Red Sea with the Indian Ocean, are used to estimate the heat and freshwater budgets of the Red Sea. The observations consist of 18-month records from transport resolving current-meter arrays and temperature-salinity chain moorings that allow accurate heat and salt fluxes through the strait to be determined. The new measurements account for the seasonally reversing surface-layer flow in the strait and the summertime intrusion of low-salinity thermocline water from the Gulf of Aden. The annual mean freshwater loss to the atmosphere over the Red Sea is estimated to be 2.06 +/- 0.22 m yr(-1), while the annual mean heat loss is 11 +/- 5 W m(-2). These results are compared with previous estimates of the Red Sea heat and freshwater budgets derived from both direct and indirect methods, which show large differences between each other and much larger uncertainties than the present estimates. (C) 2002 Elsevier Science Ltd. All rights reserved.