(2011). The smallest trends occurred along the east coast of Sweden 0.3 to 0.5 °C decade− 1 compared to 0.5 to 0.9 °C decade− 1 in the central part of the Baltic Proper. Those authors postulated that the decrease in the warming trend along the coast was due to increased upwelling connected with Z-VAD-FMK ic50 a shift in the dominant wind directions. Our trend analysis of favourable wind conditions derived from the wind station data May–September for the period 1990–2009 support this hypothesis (Figure 11). There is a positive trend of south-westerly and westerly wind conditions along the Swedish

coast and the Finnish coast of the Gulf of Finland and a corresponding negative trend along the east coast of the Baltic Proper, the Estonian coast of the Gulf of Finland and the Finnish coast of the Gulf of Bothnia. September contributes most to this trend, whereas in June and August the trend undergoes a partial reversal. The present paper extends the statistical investigation of Baltic Sea upwelling to cover the entire area of the sea for the first time. For Staurosporine mouse the period 1990–2009, weekly maps based on NOAA/AVHRR satellite data were used to analyse the locations and frequencies of upwelling along the Baltic Sea coast. These characteristics compare very well with earlier studies, also based on satellite observations (Gidhagen, 1987 and Bychkova et al., 1988).

Additionally, daily SST fields derived from a coupled sea ice-ocean model run were analysed for the same period. The statistical analysis was carried out over the thermally stratified period from May to September but also for each individual month. Different methods and various thresholds were applied to different data sets (satellite observations and numerical model results). The overall agreement of the derived statistics was very high, which confirms the robustness of the results. Upwelling events occurred most frequently along the Swedish east coast and the Finnish coast of the Gulf of Finland. Upwelling

frequencies Rapamycin were related to prevailing wind conditions during particular months and the orientation of the coastline with respect to the wind direction. For the period 1990–2009 a positive trend of upwelling frequencies along the Swedish east coast and the Finnish coast of the Gulf of Finland was calculated, which is in accordance with the positive trend in the wind conditions forcing upwelling, i.e. an increase in south-westerly winds over the Baltic Proper and more westerly directions over the Gulf of Finland. A negative trend occurs along the east coast of the Baltic Proper, the south coast of the Gulf of Finland and the Finnish coasts of the Gulf of Bothnia. For our analysis we assumed a fixed mixed layer depth, which of course varies during the summer and from year to year. For a deep mixed layer the necessary wind impulse to force upwelling is larger than for a shallow mixed layer in order to produce a signal in SST (Haapala 1994).