The hydrographic-hydrochemical state of the Baltic Sea in 2015

For the southern Baltic Sea area, the “cold sum” of the air temperature of 19.8 Kd in Warnemünde amounted to a very warm winter in 2014/15 and ranks as 7^th warmest winter since the beginning of the record in 1948. The summer “heat sum” of 182.3 Kd is in the upper midrange over the past 68 years and ranks on place 21 of the warmest summers.

The situation in the deep basins of the Baltic Sea was mainly coined by the Major Baltic Inflow of December 2014 which was the third largest ever observed. In May 2015, the layer between 140 m and the bottom in the eastern Gotland Basin was completely ventilated. In 2015, inflow events with estimated volumes between 141 and 270 km³ occurred on five occasions. In conclusion, intensified water exchange processes were recorded in the last two years and some inflow pulses were able to reach the bottom water of the central Baltic Sea fostering the large Major Baltic Inflow of December 2014 with subsequent consequences for the biogeochemical cycles.