Operational system for automatic coastal upwelling detection in the Baltic Sea based on the 3D CEMBS model

Abstract

The upwelling in the Baltic Sea region is very common phenomenon. According to different studies, in some places it can exist almost one-third of the year leading to vertical mixing and transporting fresh, rich in nutrients water from deeper layers to the surface. The upwelling phenomenon has been analysed for years 2010-2016, during thermally stratified period, i.e. between May and September. Surface layer temperature from coupled ecosystem model of the Baltic Sea - 3D CEMBS was analysed together with NOAA/AVHRR satellite SST observations. Wind data from weather forecasting model - UM from ICM UW were also analysed to describe favourable conditions for the upwelling occurrences. The research includes statistical analysis of entire Baltic Sea region as well as particular examples from selected areas. Areas of upwelling occurrences were found along almost entire coastline of the Baltic Sea. Main areas were located along Swedish coast in Baltic Proper, Oland and along Finnish coast in the Gulf of Finland, where the event can last up to 30% of the time. Other areas, with frequencies over 20%, include Polish coast, Gotland and Bay of Bothnia. It was determined that collected results were in good agreement with earlier studies, with satellite data giving slightly higher frequencies closer to the shore. Based on these results, an automated coastal upwelling detection system was designed and launched in operational mode together with the 3D CEMBS model.