摘要
利用中尺度模式WRF V2.2对超强台风"桑美"(2006)进行数值模拟,在模式较好地模拟出台风路径和强度及其近海突然增强过程基础上,分析在"桑美"近海突然增强过程中,环境场中的干冷空气在湿度场和温度场上的表现特征以及对近海台风突然增强的作用及其可能机制。结果表明:"桑美"在近海突然增强与环境场中干冷空气活动密切相关,高时空分辨率的FY-2C气象卫星水汽图像可以形象地揭示出台风发展演变过程中干冷空气的发展演变特征,干冷空气在高层的范围和强度明显强于中层。随着"桑美"西北侧的干冷空气不断靠近台风环流,台风在近海发展加强;而随着"桑美"西南侧干冷空气逐渐逆时针卷入台风环流,台风开始减弱。干冷空气沿着等熵面由高层向中层、由高纬向中低纬入侵,在"桑美"北上时,两者发生相互作用,"上干下湿"的层结分布,有利于台风增强。干冷空气与沿西北向移动的暖湿台风环流系统发生相互作用,干冷空气及其穿越等熵面的下沉运动所产生的冷平流效应有利于台风发展;干冷空气随着等熵面高度的下降出现明显西倾,有利于台风发展。
Employing the meso-scale WRF（Weather Research and Forecast）model, Super Typhoon Saomai （2006） is simulated. The variation of track and intensity and its offshore rapid intensification process are well demonstrated by the model, and the temperature and humidity patterns associated with the dry cold air activity and their impact on and mechanism of the offshore rapid intensification of Saomai are mainly studied in this paper. The results indicate that high-resolution water vapor imagery can visually reveal the development, evolution, interaction as well as the mutual complementation of the dry cold air activity accompanied with the development of Saomai. The offshore rapid intensification phenomenon of Saomai is closely related to the dry cold air which originates from the upper- and mid-troposphere. Besides, the dry cold air from the upper troposphere is stronger than from the mid-troposphere. Saomai intensifies as the dry cold air from the northwest moves toward its circulation but weakens when the dry cold air from the southwest is drawn into the storm. Dry cold airflows and their cold advection effect caused by the downward motion across the isentropic surface are favorable to the development of Saomai. The dry cold air always moves along an isentropic surface from the upper troposphere to the mid-troposphere around the typhoon circulation and contributes to Saomai＇s abrupt intensity change.
出处
《热带气象学报》
CSCD
北大核心
2015年第1期21-31,共11页
Journal of Tropical Meteorology
基金
国家自然科学基金(40730948
40875030
41475041)共同资助
关键词
天气学
台风
强度突变
WRF模式
干冷空气
synoptics
typhoon
rapid intensity change
WRF model
dry cold air
作者简介
通讯作者：于玉斌，男，江苏省人，研究员，博士，主要从事热带气旋研究。E-mail：yuyb@ema．gov．cn
