Atmospheric teleconnections between the Arctic and the eastern Baltic Sea regions

Abstract

The teleconnections between meteorological parameters of the Arctic and the eastern Baltic Sea regions were analysed based on the NCEP-CFSR and ERA-Interim reanalysis data for 1979-2015. The eastern Baltic Sea region was characterised by meteorological values at a testing point (TP) in southern Estonia (58°N, 26°E). Temperature at the 1000ghPa level at the TP have a strong negative correlation with the Greenland sector (the region between 55-80°gN and 20-80°W) during all seasons except summer. Significant teleconnections are present in temperature profiles from 1000 to 500 hPa. The strongest teleconnections between the same parameter at the eastern Baltic Sea region and the Arctic are found in winter, but they are clearly affected by the Arctic Oscillation (AO) index. After removal of the AO index variability, correlations in winter were below ±0.5, while in other seasons there remained regions with strong (| R | > 0.5, p < 0.002) correlations. Strong correlations (| R | > 0.5) are also present between different climate variables (sea-level pressure, specific humidity, wind speed) at the TP and different regions of the Arctic. These teleconnections cannot be explained solely with the variability of circulation indices. The positive temperature anomaly of mild winter at the Greenland sector shifts towards east during the next seasons, reaching the Baltic Sea region in summer. This evolution is present at 60 and 65° Nbut is missing at higher latitudes. The most permanent lagged correlations in 1000ghPa temperature reveal that the temperature in summer at the TP is strongly predestined by temperature in the Greenland sector in the previous spring and winter.