Observations on the Circulation in the Alboran Sea Using ERSI Altimetry and Sea Surface Temperature Data

Abstract

Data from the altimeter onboard the European Remote Sensing Satellite (ERSI) was used to Study the circulation of the Alboran Sea between 35° and 38°N, 0° and 6°W. This region is dominated by two anticyclonic gyres that are quasi-stationary in space but at times collapse over periods as short as 9 days. Maps of sea level residual, between February 1992 and December 1993, were created from the ERSI data with high correlation between sea surface temperature and residual sea level in the eastern part of the Alboran Sea. The spatially coherent signal was then extracted using the technique of complex empirical orthogonal analysis with the first three modes statistically significant. The variability of the first complex empirical orthogonal function mode appears to be associated with the incoming jet through the straits of Gibraltar with three time periods of high amplitude during the 1992?93 time frame. The second and third modes appear to be associated with the variability of both the western and eastern gyres. Westward propagation in the third mode is evident in the area of the eastern anticyclonic gyre and consistent with previous model simulations. The results indicate that combining sea surface temperature data and sea level data from altimetry holds promise for understanding the circulation of the Western Mediterranean.