engleski

Istrian Coastal Countercurrent in the year 1997

During the 1966-1997 period the Istrian Coastal Countercurrent (ICCC), i. e. the strong southward surface current confined to the coastal belt off Istria, up to 20 Nm wide, appeared and was particularly pronounced in August of those years when mucilage or anoxia events occurred in the northern Adriatic (1977, 1988, 1989, 1991, 1997). In this paper we analyse geostrophic currents and hydrographic characteristics of the northern Adriatic in 1997. We show that the ICCC can appear in months other than August, as well as that its occurrence implies the presence of an anticyclonic gyre in the northeastern Adriatic, in which lower salinity waters, originated in the Po Delta area, are confined. Longer residence times of this nutrient rich waters can favour eutrophication process and mucilaginous aggregate accumulation. On the basis of the prediction formula derived for the 1966-1992 period we was able to predict the intense episode of the ICCC ; really verified in August 1997 from air-sea heat flux calculations with -7 months time lag and Po River discharge rate with -1 month time lag.

northern Adriatic Sea; heat and water surface fluxes; Po river runoff; geostrophic currents; mucilaginous aggregates

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