三类沙尘暴过程环流特征和动力结构对比分析  

Comparative Analysis on Characteristics of Circulation and Dynamic Structure in Three Types Duststorm Processes

作　　者：姜学恭 云静波 

机构地区：[1]内蒙古自治区气象台,呼和浩特010051

出　　处：《高原气象》2014年第1期241-251,共11页Plateau Meteorology

基　　金：国家自然科学基金项目(41365003;40965005)

摘　　要：利用地面、高空气象观测资料、NCEP再分析资料等对冷锋、蒙古气旋、高压底部倒槽型3类天气过程的大尺度环流、动力和热力结构特征进行了对比分析。结果表明，从大尺度环流特征来看，冷锋型、蒙古气旋型均在高纬地区形成尺度较大的槽涡，槽涡底部出现低槽分离并向南发展，在中纬度诱发地面冷锋及蒙古气旋，其差异在于蒙古气旋过程中往往在中纬度对流层中低层形成切断低涡；蒙古冷高压底部倒槽型过程中，中高纬度为脊前西北气流，中纬度蒙古冷高压与向北发展的倒槽在中纬度相遇形成准静止锋，并在其南侧诱发沙尘暴。从动力、热力结构来看，冷锋型、蒙古气旋型在对流层中低层均呈现典型的斜压结构，冷锋型过程锋区异常陡立，700hPa以下近于垂直，上升运动呈倾斜形态，并在对流层中低层形成高值中心；蒙古气旋型过程中，气旋区形成8～10个纬距上升气柱，贯穿整个对流层；蒙古冷高压底部倒槽型过程中，沿经向700hPa以上形成南北风的明显交汇，而在其下方形成南侧沙尘区上升、北侧高压区下沉的垂直正环流。The cold front, Mongolia cyclone and surface inverted trough at bottom of Mongolia cold high types are the main weather systems inducing duststorrn processes in North China. The characteristics of circulation and dynamic structure were comparative analysed by using observational data. The results show that the cold front type and the Mongolia cyclone type processes formed the planetary-scale trough （low） in the high-latitude area. Its separated low developed southwards. It induced the development of cold front （ or Mongolia cyclone）. Their difference was a cut-off vortex formed in the mid-lower troposphere in the Mongolia cyclone type process. On the surface inverted trough at bottom of Mongolia high process, the northwest wind stream was dominant in the mid-high latitude area. The Mongolia cold high moved southwards and encountered the northwards developed in- verted trough and induced a quasi-stationary front formed there. The duststorm appeared in south of the quasi-sta- tionary front. In both of the cold front and Mongolia cyclone ]processes, a typical baroclinic structure formed in the mid-lower troposphere. In the cold front process, the cold front zone was nearly perpendicular to the surface below 700 hPa. A slope ascending air stream appeared and formed a center in the mid-lower troposphere. In the Mongolia cyclone process, an perpendicular ascending air stream column formed at the cyclone area and spread to 8 ~ 10 latitudes horizontally and to the whole troposphere vertically with the positive vorticity. In the inverted trough process, along the meridional direction an evident intersection area between the southern and northern wind appeared above 700 hPa. Below it, a positive circulation formed with its ascending branch locating in the duststorm area while its down sinking branch appearing in the cold high area.

关 键 词：沙尘暴 天气系统 大尺度环流 动力热力结构 对比分析 

分 类 号：P445.4[天文地球—大气科学及气象学]