Long-term changes in water level of the northwestern part of the Black Sea

The characteristics of sea water level (SWL) in the northwestern part of the Black Sea and the main influencing factors were studied. Based on observation data, it was found that the mean SWL at hydrological stations along the coast is similar. Over the past four decades, an increase in SWL has been observed, with an average rate of about 3.3 mm per year. This rise is comparable to the average increase observed in the World Ocean. Since about 2000, the increase in level has practically disappeared. It was shown that this feature is caused by the changes of the Black Sea water balance. The increase of air temperature in the studied region is greater than worldwide. This increase is observed alongside with the increase in water temperature and a significant increase in evaporation from the sea surface. The inflowing river runoff, which has been less than usualin recent years, also has an effect on SWL. In addition to long-term changes, seasonal fluctuations also occur. During a year, the smallest increase is observed in May and June, the largest – in November and February. The intra-annual distribution of water runoff from the Danube and Dnipro rivers is the primary factor that influences the seasonal changes of SWL.