Multidecadal climate variability dominated past trends in the water balance of the Baltic Sea watershed

Abstract The Baltic Sea watershed includes the territories of 14 countries in Northern, Central, and Eastern Europe. Long-term observations have shown that climate this area is characterised by a pronounced multidecadal variability, with period about 30 years, but its origin thus far unknown. We propose observed ~30-year fluctuations salinity are caused Atlantic Multidecadal Variability North Oscillation, which together modulate precipitation over hence river discharge into Sea. return large portion outflowing brackish water inflowing salt water, due to mixing at entrance results positive feedback mechanism amplifies variations salinity. strength self-amplification considerable since atmospheric forcing has nearly same periodicity as response time freshwater content external inputs.