Seasonal, Regional, and Interannual Variations of SST in the Baltic Sea

The overview about the monthly mean sea surface temperature maps of the investigation period 1990-2005 presented in Fig. 9.1 displays the strong seasonal and interannual variations. The implemented monthly means of the entire period (bottom row) show the typical seasonal cycle and the yearly mean values (right column) the increase in temperature in the last years. The seasonality is characterized by a variation range of the monthly mean temperatures from 0°C up to 22°C. The seasonal variations of the sea surface temperature are 

FIGURE 9.1 Monthly mean sea surface temperature maps from the investigation period 1990-2005 including the monthly means of the entire period (bottom row) and the yearly mean temperatures (right column). (See color plate) 

These main tasks, the seasonality, the regional differences, as well as the long-term temperature development, are subject of further detailed investigation. 

While the mean maximum of air temperature occurs between July and August, the maximum S ST is reached normally in August, as seen in Fig. 9.2 where seasonal variations of all monthly mean SST for the investigation period and the mean values for the entire period are presented. 

The mean seasonal cycles of the investigation period reflect the expected course of the temperature development. In the period of the winter minimum in February/March, the sea surface temperature varies between — 1 °C and 1 °C except in the warmest winter 1990. 

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