中国大地形对冻雨天气云微物理过程的影响

云贵高原的冻雨是中国南方冬季最严重的气象灾害。利用天气研究和预报模式(weather research and forecasting model, WRF),对云贵高原大地形进行了敏感性实验，模拟了不同地形高度对大气环流、云微物理参量及冻雨分布的影响，结果显示：随着云贵高原大地形的抬升，准静止锋的锋线一直维持在24°N附近，但锋面越来越陡，表明高原大地形是形成云贵准静止锋的主要因素，准静止锋长时间滞留在贵州中东部和湖南西部，是该区冻雨高发的原因。随着高原的抬升，从全境的云滴碰并增长逐渐在高原东部出现冰晶融化过程，高原主体上的冻雨以过冷暖雨机制为主，而低海拔的东部地区以融化机制为主。随着高原抬升，高空逆温层及冻雨区均从贵州西北向贵州中部及东部地区移动，逆温层的存在及其冷-暖-冷的垂直结构是冻雨形成非常重要的因子。当云贵高原降至原地形的一半时，冻雨量最大，其后随着高原抬升，冻雨量开始减少。该研究有助于更深入了解云贵高原大地形对冻雨形成、范围和强度的影响机制。

Seneitivity of Large Topography on the Formation and Cloud Microphysics of Freezing Rain in China

The freezing rain in Yunnan-Guizhou Plateau is the most serious meteorological disaster in winter in southern China. By using the Weather Research and Forecasting model (WRF) model, the influence of the Yunnan-Guizhou plateau on the formation, distribution, and Cloud Microphysics with freezing rain was analyzed. The results show that: 1) With the increasing of the topography, the slope of the quasi-stationary front has gradually increased and the frontal line has been maintained near 24°N. This phenomenon indicates that the Yunnan-Guizhou Plateau is the main factor in the formation of the quasi-stationary front in Yunnan-Guizhou. The quasi-stationary front stays longer in the central-eastern part of Guizhou and western Hunan, resulting in a high incidence of freezing rain in this region; 2) With the lifting of the plateau, the cloud droplets from the whole region gradually collide and grow in the eastern part of the plateau with the ice crystal melting. The freezing rain on the main region of the plateau is dominated by the supercooling warm rain mechanism, while the melting mechanism dominates the eastern part of the low altitude. 3) With the lifting of the plateau, the high inversion layer and the freezing rain area both move from northwest Guizhou to central Guizhou. The inversion layer and its cold-warm-cold vertical structure are essential in the formation of freezing rain. The amount of freezing rain is greatest when the Yunnan-Guizhou plateau descends to half of its original topography, and then decreases with the plateau rises. This study deepens the understanding of the mechanisms that influence the formation, extent, and intensity of freezing rain on the large topography of the Yunnan-Guizhou Plateau.