Climatological analysis on the North-Western Black Sea upwelling phenomena

We used monthly means by Copernicus Marine Services for the Black Sea basin to calculate a series of metrics related to wind-driven upwelling dynamics (Upwelling Index) and examine the relationship with nutrient and plankton environment. We then use these to objectively describe upwelling signals in terms of their frequency, intensity and duration during summer months over 26 years (1993 - 2019). We found that an increase or a decrease in the sea surface temperature is associated with a reduction (or increase) in upwelling events, a decrease/increase in the intensity of upwelling, and a decrease/increase in the cumulative upwelling intensity, with differences between Romanian Black sea areas. Nitrate supply by coastal upwelling has been estimated by combining sea surface temperature and salinity for the in-situ data for the North-Western Black Sea shallow waters. The seasonal vertical transport induced by wind forcing was assessed by daily wind data retrieved from the Copernicus Marine Service data was used.