AUTHOR=Skudra Māris , Väli Germo , Ikauniece Anda , Papirtis Miks 

TITLE=Upwelling characteristics in the Gulf of Riga (Baltic Sea): multiple data source approach

JOURNAL=Frontiers in Marine Science

VOLUME=Volume 10 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2023.1244643

DOI=10.3389/fmars.2023.1244643

ISSN=2296-7745

ABSTRACT=Upwelling events in the Gulf of Riga during 2010-2022 were studied by analyzing sea surface temperature time series from coastal stations and smartbuoy, together with satellite data, model data and CTD surveys. Starting/end point, active and relaxation phase was defined in each event to describe characteristics and length of each phase. Upwellings were less frequent (41%) at the eastern coast but lasted longer and had higher temperature drop than at the western coast. At western coast variety in upwelling characteristics between stations only 30 km apart were found with likely reason being the different orientation of the coastline in respect to the wind direction.Satellite data revealed that in the western coast of the Gulf rather small upwelling events form along specific sections of the coastline. 30% of all upwelling events were characterized by immediate temperature increase after reaching the minimum temperature and we suggest that this is related to distinct change of wind direction. The results from the simulations indicated smaller lateral density and salinity gradients in the sea surface than in a larger Baltic Sea gulfs. It signals that conditions for the occurrence of baroclinic instabilities are rather small, thus, we suggest that weaker gradients could explain quite fast upwelling relaxation in the basin if compared to, e.g., the Gulf of Finland.