关键词: 北京2022冬奥会, 山地气象, 冷空气湖, 观测实验

Abstract: Based on the observations of thermometers installed at the slopes and bottom of the valley in Chongli zone for Beijing 2022 Olympic winter games, the temperature variations at different heights under different circulation backgrounds from 4 to 18 March 2019 were analyzed, and the law of emergence and breaking of the cold air lake at night under special terrain conditions has been revealed. The results show that under the non-stationary situation, there was normal temperature stratification in the vicinity of the experimental stations and no cold air lake developed. Under the stationary situation, there was obvious cold air lake in the valley. Due to the special topography of the area, the east-southeast wind at the valley bottom appeared together with the cold air lake and the depth of the cold air lake was related to the degree of the weather static stability and changed dynamically with time. The development or disappearance of the cold air lake was directly related to the wind speed. When large-scale system wind was weak, the gravity wind played a leading role in the valley and cold air lake developed. When the large-scale system wind was strong, it played a leading role and increase of wind speed led to the enhancement of wind shear and the generation of turbulence, which mixed downward momentum with warm air. Also the airflow over the mountain led to foehn effect, then the structure of the cold air lake disappeared.

Key words: Beijing 2022 Olympic winter games, mountain meteorology, cold air lake, observation experiment