Vortex structures in the Southeastern Baltic Sea: satellite observations and concurrent measurements

Abstract

Vortex structures of different types are common in the Southeastern Baltic Sea. Intensive western winds, a complex coastline and an absence of steady currents make this region very appealing for studying the nature of vortex processes. These processes are clearly identified from Space. We present results of a multi-year satellite monitoring of mesoscale and submesoscale vortex structures in the Southeastern part of the Baltic Sea and of supporting field studies. An important part of our work was accumulation of remote sensing data as the first step in evaluation of circulation patterns and vortex structures presented on the sea surface. An analyzed remote sensing data include color composite images from MSI Sentinel-2, OLI Landsat-8 and ETM+ Landsat-7 as well as radar images from Sentinel-1 and Radardsat-2 that also provide a powerful tool for an identification of circulation processes on the sea surface. Continuous monitoring of the Southeastern Baltic Sea with an analysis of satellite visual and radar images show that the Gulf of Gdansk is the most frequent area with mesoscale and submesoscale eddies. They appear in this area mostly in summer and mainly under the atmospheric influence. Some eddies remain stable for at least of 8 days and could be easily tracked on color composite images. The other area of the vortex structure was determined to the north of the Cape Taran. In summer months from 2014 to 2018, we performed oceanographic concurrent experiments in the southeastern part of the Baltic Sea. Field studies of spatial and temporal characteristics of vortex structures proved results found by an analysis of satellite images.