Snow water equivalent variability and forecast in Lithuania

Atmosphere circulation is the most important modulator of snow cover parameters. This study deals with the relation between the dominant Northern Hemisphere circulation mode, called the Arctic Oscillation (AO), and the spatial distribution of the snow water equivalent (SWE) within the territory of Lithuania. The results indicate an inverse relation between the extreme AO phase and the SWE. However, the largest spatial differences are seen in the positive AO phase. The absolute altitude and slopes expositions play a more significant role in that case. During the extreme negative AO phase, a decreasing temperature as a function of distance from the seacoast from west to east becomes more significant to the accumulation of snow cover. The study also includes a climatic forecast for changes in the snow water equivalent based on the outputs of five climate models. Under an increasing winter air temperature and rain fraction in winter precipitation, the SWE will decrease distinctly causing a change in river feeding regime.