Abstract:In this study, based on precipitation observation data and ERA5 reanalysis data of Haituo Mountain from 1 January to 15 March of 2019-2021, the 34 winter precipitation processes in Haituo Mountain were classified. The characteristics of observed precipitation at different altitudes under different weather types were analyzed statistically. The results were as follows. According to the influence of weather system and terrain, the winter precipitation in Haituo Mountain can be divided into four weather types: northerly airflow type, easterly airflow type, low eddy trough type, and backflow low eddy trough type. Under different weather types, the direction and intensity of the airflow, the vertical distribution of water vapor and other conditions below the topographic height of Haituo Mountain as well as the interaction with the topographic conditions, make significant differences in precipitation and its duration between different altitudes. The northerly airflow type is controlled by the strong northerly airflow in the whole layer behind the 500 hPa trough, forming the airflow passing over mountain, and the precipitation is concentrated in the high-altitude area. The easterly airflow type is affected by the easterly airflow at the lower level, and the precipitation is concentrated in the low-altitude area. The above two weather types have no synoptic-scale system to accompany, and are dominated by topographic forcing, so the precipitation is small in amount, lasting for relatively short time. The low eddy trough type is affected by the high-altitude eastward movement of low trough, accompanied by the low level southwest airflow, which makes more precipitation at high-altitude area, and this type is also the most frequent weather type in Haituo Mountain in winter. Backflow low eddy trough type is affected by the low trough, with easterly backflow before precipitation to humidify the lower level and play a role of cold cushion, so the precipitation in low-altitude area is more. The above two weather types have synoptic-scale systems, superimposed by the topographic effect of Haituo Mountain terrain, which causes significant precipitation and its long duration, affecting the game run. The above results have been applied in the forecast of a heavy snowfall process during the 2022 Beijing Winter Olympics Games, and proved that the statistical results of the above characteristics can play a role in the forecast of precipitation over complex terrain of Haituo Mountain in winter.