Abstrakt
The change in precipitation phase is an important manifestation of climate change, especially in the moderate climate zone and mountain regions. We analyse changes in precipitation at 107 European stations in cold months (November-April).
Stations in Czechia where both surface synoptic observations (SYNOP) reporting the precipitation phase, and temperature and precipitation data are available in sufficient quality, are used to determine the regional threshold temperature. The threshold temperature is then applied to separate solid and liquid precipitation phase in cold months at European stations in 1961-2010.
If daily mean temperature is higher than the regional threshold temperature, daily precipitation amount is considered to be liquid and vice versa. The value of the regional threshold temperature is 1.1 degrees C.
The ratio of solid to total precipitation (S/P) significantly declines over large parts of Europe. The strongest negative trend is detected in the belt stretching from the coast of northern Scandinavia through central and eastern Europe towards southern and southeastern Europe.
The trend of S/P ranges from -0.2 to -0.9%.year(-1) there. The average annual trend of the ratio of solid precipitation for all Europe is - 0.12%.year(-1).
The magnitude of the trend of the ratio of solid precipitation exhibits only a minor sensitivity to the choice of the threshold temperature. A comparison with real trends, calculated for stations in Czechia, indicates that trends determined from the threshold temperature tend to be overestimated, that is, the decline of solid precipitation in Europe is even faster that what results of this study indicate.