Sea heat waves. Disturbing phenomenon
From 1951 to 2020 Air temperature in the area of the Polish Baltic coastU increased by 0.29 degrees Celsius/10 years. IMGW He emphasizes that “one of the most disturbing manifestations of these changes are – more and more often appearing from a year by a year stronger – Marine Heatwaves (MHWS)”. Studies conducted by scientists from the Institute of Maritime Research of the University of Klaipedza showed that in the years 1993-2023 in the south-eastern part of the Baltic Sea Waves of heat occurred almost every year, and their duration was constantly extended.
“Typical values for tropical seas”
It turns out that in 2021 the phenomenon was observed for up to 60 days, and in the early 1990s there were less than 7 days). In the same year, in July, the average water temperature exceeded the norm by over 4 degrees – reaching a maximum of 25.5 degrees C. “These are typical values for tropical seas” – we read on the IMGW website. However, this is not the end of bad news. In 2022, large areas of the Baltic Sea were one of the warmest measurements in history. As many as 7 MHW episodes were recorded in the Danish straits, with anomalies of 4.6 degrees above the norm. However, the Botnicka Bay was observed Increase in water temperature by up to 9.6 degrees C.
“Fatal influence on the reproductive capabilities of fish”
In addition, sea heat waves occurred not only in the surface layer of the Baltic Sea, but reached to a depth of almost 20 meters. For a relatively shallow basin, this is of great importance. “Waves reaching the sea bottom they contribute to a drastic decrease in concentration oxygen and thus are an additional factor affecting the enlargement of the bottom water zone with a reduced content of this element ” – I'm writing IMGW. Scientists point out that intensification of sea waves of heat It will have a fatal impact on the reproductive capabilities of fish and the entire Baltic ecosystem.
Heat waves in the Baltic Sea. What causes them?
IMGW reports that the main factor creating the atmosphere of the Baltic Sea “is the variability of atmospheric circulation over the northern Atlantic.” As we read, “Baltic – being a shallow sea, half -hilly, with low salinity – is particularly susceptible to heating and accumulating heat. Limited water exchange with the North Sea It causes heat to accumulate in the Baltic Sea faster and stays longer. “However, low salinity” hinders the mixing of warm surface water with cool bottom waters. ”
Disturbing forecasts
IMGW reminds that in 2022 a team of scientists from the Leibniz Institute for Baltic Sea Research in Germany conducted climate projects for the Baltic Sea until 2100. They show, among others, that large areas of the Baltic Sea will experience MWh on average once a year. However, in some areas – e.g. the Bay of Riga or Finnish – heat waves may appear 2-3 times a year, and in the Botnicka Bay take up to about 20 days. “According to researchers, until the end of the current century The Baltic Sea will certainly continue to insulate. The expected growth will be from 1.1 degrees C to even 3.2 degrees Celsius ” – we read on the IMGW website.
See also: Sea and Arctic Ice. New data. More in the text “Disturbing. It has not been so for 47 years. They took a closer look at the sea and arctic ice. Records were fallen” “.
Source: IMGW observer