Investigation of the response of the Aegean Sea to the Etesian wind forcing

Abstract The response of the Aegean Sea to seasonal forcing by the Etesian winds is investigated, based on Copernicus products for weather forecasting (winds) and satellite information (sea-surface temperature (SST) and chlorophyll-α (chl-a) concentration), as well as fisheries records from the Hellenic Statistical Authority. To that end, a site-specific response criterion for upwelling intensity has hereby been developed, based on the zonal SST gradient between eastern and western Aegean. Combined use of the above criterion with lagged cross-correlation between wind, zonal surface temperature gradient, surface chl-a concentration and local fish landings reveals a well-hidden (until now) signal of chl-a increase in response to intensification of wind forcing, as well as a relation between fish landings and upwelling events, challenging the conclusions of previous studies suggesting that the Aegean Sea is immune to summer coastal upwelling, due to the great depth of its nutricline.