Mesoscale eddies in the area of peter the great bay according to satellite data

We have studied the characteristics of mesoscale eddies in the Peter the Great Bay and the adjacent area of the northwestern Sea of Japan. The characteristics were determined using infrared images (NOAA/AVHRR satellite data) for July-October periods of 2000-2004. It is established that anticyclonic eddies are always present in the indicated area, since they have been identified on 85% of the available cloudfree images. Characteristics of 43 anticyclonic eddies have been determined. Their diameters vary from 20 to 110 km, with the most probable sizes within 20-60 km. The typical eddy lifetime varies from 3 to 30 days. However, some medium-sized eddies (40-60 km) have been observed for a longer time (up to 40-60 days) and large eddies (60-110 km in diameter) remained for up to 1-2 months. Eddies drift southwestward and southward along the continental slope at a typical speed of 3-6 cm/s. There are interannual variations in the vortex structure of water flows in the area studied, which are manifested by the presence of a single large eddy occupying a large part of the bay in some years (2000, 2002, and 2003) or by the formation of several smaller eddies (2001 and 2004). The eddies contain warmer and less saline shelf waters (compared to the surrounding water) and transport it in their cores over quite a long distance. Thus, eddies are an essential element of the process of the intermediate low-salinity water-mass formation in the Sea of Japan. In addition, eddies play important role in the cross-shelf water exchange, providing rapid ventilation of the coastal zone and determining the variability of the biological processes.