Remote Sensing of Coastal Upwelling in the SE Baltic
Kozlov, Igor¹; Dailidienė, Inga²; Mingelaitė, Toma²; Chapron, Bertrand^3
1SOLab, RSHU / Klaipeda University, RUSSIAN FEDERATION; ²Klaipėda University, LITHUANIA; ³IFREMER, FRANCE

In this work coastal upwelling events in the SE Baltic Sea based on Terra/Aqua Moderate Imaging Spectrometer (MODIS) infrared imagery between 2000 and 2012 are analyzed. The MODIS-based SST data set provides valuable information on important spatio-temporal parameters of upwelling front, as well as reveal distinct dynamical features associated with its evolution.
Main statistical properties of the upwelling in the SE Baltic for the whole study period were calculated. The maximum observed SST gradients across the front were up to 1.2 °C/km, temperature drop up to 15 °C, with total upwelling-affected area being up to 18000 km2. The duration of the upwelling in this part of the sea may reach up to several weeks.
In general, the structure of the upwelling front, its time evolution and the form of generated filaments appear to be predominantly shaped by the bottom topography. The spatial distribution and main parameters of the upwelling filaments were calculated. The maximum observed horizontal offshore velocities of the filaments reached up to 0.5 m/s, they were up to 120 km in length and and up to 25 km wide with associated temperature anomalies up to 5°C. It is shown that these filaments may be responsible for intensive cross-frontal water exchange between upwelling zone and open sea.
Moreover, it is shown that under certain wind conditions water exchange at the entrance of SE Baltic lagoons, namely the Curonian and the Vistula lagoons, may be severely changed. For the cases of intensive upwelling, the strong inflows of relatively cool and more salty upwelling waters to the lagoons is registered and leads to the formation of pronounced density gradients in the lagoons.

Core support of this research was provided by Russian Government via Mega-Grant No. 11.G34.31.0078.