ON FORECASTING LONG-TERM VARIATIONS OF WATER LEVEL IN LARGE LAKES

Abstract

The paper assesses the present-day state and long-term forecast of intrasecular oscillations of water level in large Eurasian lakes. The analysis of the North Atlantic climate change influence on the catchments hydrological regime of the Caspian Sea and Ladoga and Onega lakes was made on the basis of the reanalysis data and numerical simulation results. The connection between some indexes of atmospheric and oceanic circulation describing climatic variability of the North Atlantic and Europe and hydrological regime of Volga and Neva rivers basins was estimated. The paper investigates the causal effects between climatic characteristics and catchments hydrological regime and the lakes water level. Several years’ time lag of hydrological regime (rivers runoff, the Caspian Sea level) response to changes in atmospheric circulation was shown. The dynamics of precipitation in the Caspian catchment correspond to changes in circulation indexes. Moisture transport from the Atlantic to the European part of Russia in the 21st century was estimated using the combined scenario of climate changes based on the hybrid of greenhouse and cyclic effects. The simulation results reveal possible decrease of moisture transport and atmospheric precipitation over the European part of Russia for the next 15-20 years resulting (with several years’ time lag) in the ongoing water level decrease in the Caspian Sea and Lake Ladoga. Moisture transport increase is expected from around 2035 to 2070, which will presumably lead to precipitation increase and water level rise in these water bodies.