The effect of thermohaline variability on the exchange through Mediterranean straits

Abstract

exchanges through straits. The primary assumption is that the exchange is determined by tlle pressure force created by the differing weights of tlle water columns on either side of the sill and by the continuity of mass required by the internal basin. This renders the exchanges insensitive to

the particular bathymetry or ynamical complications within the strait and computable from density profiles on either side of the strait. The method is applicable at time scales greater than days, and thus facilitates the resolution

of seasonal variability in therniollaline circulations and the monitoring of interannual trends. Application to the Strait of Gibraltar gave summer and winter outflows of 1.7 and 2.3 Sv, respectively. The seasonal balance

of exchanges for the Tyrrhenian Sea was computed to provide an example

of the interdependence of exchanges in basins with multiple openings. The

flow through the Strait of Sicily is driven by tlle steric-height differences between the Ionian and both the Tyrrllenian and Balearic Seas. Eastward upper layer flow was calculated to be 0.6 and 2.0 Sv for summer and winter, respectively. A cursory example is also given of the consequences of atmospheric warming on the Mediterranean circulation. It is shown that tlle vigor of thee thermohaline circulation would decline in proportion to a decline in deep-water production.