Influence of large-scale atmospheric circulation on Romanian snowpack duration

Daily data of snow depth from 104 meteorological stations across Romania were used to study the variability of snowpack for the period 1961-2010. The weather stations are fairly distributed over Romania (both spatially and with respect to elevation). Trend analysis was conducted with the Mann-Kendall nonparametric test, while the magnitude of the linear trend was estimated with the Theil-Sen method. The results show that the maximum snowpack duration is decreasing in the intra- Carpathian region of Romania, showing a clear spatial pattern. The signal is consistent and statistically significant. The influence of large-scale atmospheric circulation on continuous maximum snowpack duration in Romania was investigated using several teleconnection indices. We found statistically-significant negative correlations between winter East Atlantic and North Atlantic Oscillation patterns and the maximum continuous snowpack duration. Our findings are in agreement with recent studies on snow variability in the region, which point to a diminished snow / rain ratio since 1961.