Some Characteristics of the Surface Boundary Layer of a Strong Cold Air Process over Southern China

• Published in: Advances in atmospheric sciences Vol. 30; no. 1; pp. 210 - 218
• Main Author: 刘熙明 程雪玲 吴琼 傅敏宁 曾庆存
• Format: Journal Article
• Language: English
• Published: Heidelberg SP Science Press 2013; Springer Nature B.V; State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry,Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029; State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing 100081%State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry,Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029%Meteorological Sciences Institute of Jiangxi Province, Nanchang 330046; Nanjing University of Information Science & Technology, Nanjing 210044; Meteorological Sciences Institute of Jiangxi Province, Nanchang 330046; State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing 100081%Meteorological Sciences Institute of Jiangxi Province, Nanchang 330046
• Subjects: Aerodynamics; Atmospheric boundary layer; Atmospheric Sciences; Boundary layers; China; Earth and Environmental Science; Earth Sciences; Fluctuations; Fluid dynamics; Fluid flow; Fluxes; Freezing; Geophysics/Geodesy; Gusty winds; Meteorology; Turbulence; Turbulent flow; Wind; Wind speed; 中国南方; 动量通量; 大气边界层; 天气过程; 强冷空气; 气象观测数据; 监测数据; 风速仪; surface boundary layer; cold air; gusty wind; descending motion
• ISSN: 0256-1530; 1861-9533
• DOI: 10.1007/s00376-012-1223-8

In southern China, cold air is a common weather process during the winter season; it can cause strong wind, sharp temperature decreases, and even the snow or freezing rain events. However, the features of the atmospheric boundary layer during cold air passage are not clearly understood due to the lack of comprehensive observation data, especially regarding turbulence. In this study, four-layer gradient meteorological observation data and one-layer, 10-Hz ultrasonic anemometer-thermometer monitoring data from the northern side of Poyang Lake were employed to study the main features of the surface boundary layer during a strong cold-air passage over southern China. The results show that, with the passage of a cold air front, the wind speed exhibits low-frequency variations and that the wind systematically descends. During the strong wind period, the wind speed increases with height in the surface layer. Regular gust packets are superimposed on the basic strong wind flow. Before the passage of cold air, the wind gusts exhibit a coherent structure. The wind and turbulent momentum fluxes are small, although the gusty wind momentum flux is slightly larger than the turbulent momentum flux. However, during the invasion of cold air, both the gusty wind and turbulent momentum fluxes increase rapidly with wind speed, and the turbulent momentum flux is larger than the gusty wind momentum flux during the strong wind period. After the cold air invasion, this structure almost disappears.