Low-frequency current variability at the Straits of Crete, eastern Mediterranean

Abstract

Current meter data from six moorings are analyzed to study current variability at the straits of the Cretan Arc which connect the south Aegean Sea with the eastern Mediterranean. The three layers in which the current meters were deployed show different current characteristics. The upper layer shows evidence of the Asia Minor current in the Rhodes Strait and a clockwise eddy in the Karpathos Strait. Water in the middle layer moves slowly into the south Aegean. The bottom current meters in Kassos and Antikithira Straits recorded currents, steady in amplitude and direction, with speeds equal to or higher than those observed in the upper layer. The observations suggest a significant outflow (0.5 Sv) of Cretan Dense Water (CDW) to the Levantine and Ionian Seas. Rotary empirical orthogonal functions are used to extract and describe the coherent part of the variability. Forty-four percent of the total variability is described by the first three empirical orthogonal functions. Less than 20% of the current variability of the western strait is coherent with variability of the eastern straits. The coherent part of the variability refers mainly to periods longer than 20 days. The current meter data are compared with atmospheric pressure, showing good correlation during the first period of the measurements, when a major atmospheric pressure low passed over the Aegean. Copyright 1997 by American Geophysical Union.