Synoptic upwelling and cross-shelf transport processes along the Crimean coast of the Black Sea

Abstract

The Crimean coast along the northern periphery of the Black Sea is an area of frequent synoptic upwelling events during the spring and early summer. During June 1996, an observational program consisting of repeated hydrographic surveys, sea surface temperature from satellite imagery, and a small moored array with current meters is used to describe two upwelling events, with emphasis on the cross-shelf transport of upwelled waters. Typical minimum surface temperatures ranged between 10 and 14°C, compared to surrounding surface waters of 20°. The upwelled water near the coast translated alongshore to the west with velocities of typically 0.10 m s -1. One day after the peak wind stress, filaments of cold water developed which were directed offshore, perpendicular to the coast. The filaments were 3–10 km wide with offshore velocities inferred at 0.3 m s -1 from feature tracking of thermal imagery. Cool water was carried 60 – 80 km offshore from the coast within several days after the cessation of upwelling favourable winds. The upwelled water transits the shelf rapidly in both the along-shelf and cross-shelf directions, and the offshore filaments may be related to the Rim Current and the associated eddy field penetrating onto the continental shelf.