Abstract:

Based on the daily precipitation data, weather phenomenon, radiosonde data, and the NCEP reanalysis data with resolution of 0.5°×0.5° (part 2.5°×2.5°) during October to April from 1979 to 2012, the climate and atmospheric stratification characteristics of winter precipitation in different phase states were analyzed in Dandong. The typical cases of winter precipitation in the different phase states were discussed. The results show that although Dandong is located in the north of China, winter precipitation phase states are variety. The temperature thresholds for various winter precipitation phase states at each stratification are different in the periods of autumn-winter, winter-spring and winter. Finally the criteria for winter precipitation phase states at the different stratification are determined. The stratification temperature background (especially surface temperature) is important to appearance and conversion of precipitation phase states, which could provide references for the prediction of the dynamic precipitation phase state. Temperature at 850 hPa and below is essential to generation of precipitation phase states. The 0 ℃ line at 850 hPa is the approximate boundary between rain and snow, while that at 925 hPa is between sleet and snow or sleet and rain.

Key words: Winter precipitation, Precipitation phase states, Criteria