单多普勒雷达反演涡旋风场方法分析

Analysis of Vortex Wind Fields Retrieval Methods for Single Doppler Weather Radar

由于单雷达在探测台风临近、登陆时仍具有双部或多部雷达难以具备的优势,目前利用单多普勒雷达反演涡旋风场的方法并不多见,本文对能够反演涡旋风场的3种方法NIVAP(自然坐标系的积分VAP方法)、EVAPTC(反演热带气旋的EVAP方法)、GBVTD(地基速度追踪法)进行了比较,分别从每种方法的假设条件和数学方法以及结果精度来比较3种方法对涡旋风场的适用性。利用中尺度气旋Rankine模式模拟了纯涡旋性气旋、只有环境风场时、环境风场和辐合(辐散)同时存在时的径向速度场及风场,比较了各种情况下的反演风场和模拟风场的相似系数。在对模拟风场比较之后,选取了2014年"威马逊"台风登陆前1h、登陆时及登陆后1h的3个实测雷达资料,对比分析了3种方法反演实测资料的风场特征,3种方法中EVAPTC方法最好,GBVTD方法在应用中有一定的限制,NIVAP方法较差。

The methods for using single Doppler radar to retrieve the vortex wind fields are rare currently.This article compares three methods:NIVAP,EVAPTC,GBVTD,which can retrieve the vortex wind fields,from the aspects of assumptions,mathematical methods,and the retrieval accuracy,so to identify which is most suitable for the vortex wind field.Using the Rankine mode mesoscale cyclone to simulate the Doppler velocity and wind field with the vortex wind field only,with the environmental wind,and with both environmental wind and convergence(divergence).The similarity coefficients of wind velocity and wind direction between the simulated and the retrieval wind fields are compared.After comparing the simulated wind field,the measured data of Typhoon Rammasun at the time of one hour before landing,right landing and one hour after landing are selected.Then the characteristics of the retrieval wind fields by the three methods are compared and analyzed.The analysis shows that EVAPTC has a good performance,GBVTD has some restrictions in practical application,and NIVAP performs poorly.