双多普勒天气雷达反演大气三维风场的个例研究

根据笛卡尔坐标系下双多普勒天气雷达反演大气三维风场的理论，以2003年7月5日发生在安徽省的一次强降水过程为例，反演大气三维风场。结果表明：利用双多普勒天气雷达反演大气风场能够更加详细地反映出大气风场的三维结构。     

VAD技术三种仰角策略反演风场的比较和应用

对不同天气情况的资料分别采用单仰角VAD方法和多仰角VAD方法进行风场反演，比较了这两种算法的反演结果，提出了融合两种方法优点的自适应仰角取样方法，并进行反演比较，结果表明：单仰角和多仰角策略各有所长，采用自适应仰角取样策略结合两种方法优点，在某些场合下可以获得更有参考价值的VAD反演结果。     

多普勒雷达风场反演VAP方法的资料预处理

在分析了三类单多普勒雷达反演风场方法的基础上, 认为VAP方法是近期内可望在业务中应用的方法, 并指出VAP方法的关键是能否将原始资料中的中-U及以上尺度的风场信息过滤出来, 以消除中-V尺度以下风场信息对反演结果的影响.为此提出了二维区域滑动低通滤波方法对资料进行预处理.此外还对VAP方法的风速计算公式进行了改进以减小计算误差.     

多部多普勒雷达同步探测三维风场反演系统

“我国重大气候和天气灾害的形成机理与预测理论研究”项目首次启用双多普勒雷达组网同步观测，如何从同步观测的暴雨资料中反演三维场，具有重要的理论和现实意义，根据项目需要，建立了国内首套多部多普勒天气雷达同步探测三维风场反演软件系统，并反演出2001年7月13日由双多普勒雷达同步观测到的一个中β尺度暴雨系统的三维风场，结果显示，该三维风场结构合理，系统能满足外场试验的要求。     

相关法雷达反演风场在台风监测和分析中的应用

随着我国沿海雷达网的建设,雷达资料正逐步成为沿海气象台站台风临近登陆时的一个重要监测手段。利用相关法雷达风场反演对2001年登陆台风“百合”和“飞燕”作了环流和强度估测分析。结果表明,通过适当的质量控制,该方法可以有效地反演得到台风强风分布特征,分析精度与业务中常用的卫星估测方法相当。     

"7.23"大暴雨动力机理的双多普勒雷达反演

使用地基双多普勒雷达MUSCAT三维风场反演技术，利用宜昌和荆州双多普勒雷达同步体积扫描资料，对2002年7月22—23日湖北省境内的一次混合型大暴雨进行了三维风场的反演。分析表明，中低层的中尺度气旋和气旋性切变线是触发和维持此次大暴雨的重要动力因素；低层辐合，高层辐散的动力配置也有利于强降水系统的发生和发展。     

双多普勒雷达反演强风暴三维风场的数值试验

两部雷达测得的径向速度再加上质量连续方程可以求解大气风场，利用这一原理，以1996年6月29日发生在北京东北部京冀交界处的一次强风暴过程为例，用模式反演出风暴体的三维风场结构，误差分析表明和实况基本一致。利用模式输出的三维风场，先模拟两部多普勒雷达扫描的数据，在此基础上，进行三维风场反演，结果表明，反演得到的流场和模拟的流场总体趋势完全一致，风暴的中心位置吻合较好，上升气流和下沉气流的分布也很接近，水平速度分量反演的误差很小，基本上可以反映三维风场的真实情况。垂直速度的平均离差在各个高度上都较小，反演结果较好。     

单部多普勒雷达反演三维风场涡度—散度方法的初步研究

涡度－散度反演三维风场的方法是在反演二维风场的涡度－散度方法基础上发展得到的。其基本做法是将垂直方向的涡度方程适当简化，结合涡度和散度的定义，再以连续方程为约束，计算出风场三个方向的分量以及涡度，散度，从而反演到三维风矢量场。初步的试验资料检验结果表明，它是一种具有实用前景的三维风场反演方法。2000年，作者考虑了降水粒子的下落速度对垂直速度的影响，将该方法进一步完善。     

2008年8月1~2日滁州特大暴雨双多普勒雷达三维风场反演试验的初步结果

受“凤凰”低压和冷空气共同影响, 2008年8月1~2日安徽省东部和江苏西部部分地区出现大雨, 局部地区暴雨到特大暴雨。滁州和全椒24 h雨量分别为429 mm和414 mm, 此次特大暴雨具有局地性和降水强度大的特点。使用南京和马鞍山双多普勒雷达时间同步观测资料, 对此次暴雨的三维风场进行反演, 在此基础上, 研究了暴雨的三维风场结构。由雷达回波分析可知, 此次暴雨是由β中尺度对流系统造成的, 在β中尺度对流系统内部还有γ中尺度对流单体, 对流单体发展非常旺盛。中低层切变线自西向东移入降水区后, 在该地区停留较长时间, 加之有充足的水汽供应, 造成了局地特大暴雨。在垂直剖面内, 对流系统发展旺盛, 强降水区上空回波较强且对应着较强的上升气流区, 而在强回波中心区的两侧均有下沉气流。当切变线减弱并移出降水区后, 强降水停止。     

双多普勒雷达风场反演资料的同化应用试验

利用合肥、马鞍山2部多普勒雷达联合观测资料及多部多普勒雷达合成和连续调整技术（MUSCAT）,在笛卡尔坐标下反演得到三维风场。将得到的风场通过由CAPS（center for analysis and prediction of storm）研发的ARPS（advancedregional prediction systemv5．2．4）模式及数据处理系统ADAS（ARPS data analysissystem）进行同化试验。结果表明,反演风场信息可以改善短时模拟场、特别是风场的状况;但由于对湿度场等的改进较小,致使预报的3h降水量与实况有出入。     

ASSIMILATION METHOD FOR RETRIEVING HORIZONTAL WIND FIELD FROM SINGLE-DOPPLER DATA

Doppler weather radar can provide the wind information such as the radial velocity,and hasbecome one of the most powerful means for studies of severe mesoscale and microscale weathersystems.Usually the radar observation provides only plane position indicator(PPI)scanning dataand range height indicator(RHI)scanning data.and this makes some retrieval methods usingthree-dimensional volume scanning data impractical in operation.In order to use these data moreefficiently,a plane assimilation retrieval(PAR)method is developed using data assimilationtechnique on the PPI scanning plane.The PAR method is tested with the observation data ofChinese Academy of Meteorological Sciences(CAMS)Doppler weather radar and the result isencouraging.     

WIND SHEAR IDENTIFICATION WITH THE RETRIEVED WIND OF DOPPLER WEATHER RADAR

Wind shear reflects that the wind field is not uniform, which is one of the primary factors which make the retrieval of the wind field difficult. Based on volume velocity process(VVP) wind field retrieval technique, the intensity of wind shear is identified in this paper. After analyzing the traditional techniques that rely on the difference of radial velocity to identify wind shear, a fixed difference among radial velocities that may cause false identification in a uniform wind field was found. Because of the non-uniformity in wind shear areas, the difference of retrieved results between surrounding analysis volumes can be used as a measurement to show how strong the wind shear is. According to the analysis of a severe convective weather process that occurred in Guangzhou, it can be found that the areas of wind shear appeared with the strength significantly larger than in other regions and the magnitude generally larger than4.5 m/(s·km). Besides, by comparing the variation of wind shear strength during the convection, it can be found that new cells will be more likely to generate when the strength is above 3.0 m/(s·km). Therefore, the analysis of strong wind shear's movement and development is helpful to forecasting severe convections.     

ERROR COMPARISON OF WIND FIELD RETRIEVAL FROM SINGLE AND DUAL-DOPPLER RADAR OBSERVATIONS

The error distributions of the wind fields retrieved from single and dual-Doppler radar observations are given inthis paper.The results indicate that the error of dual-Doppler retrieval depends on the position in the scan region of thedual-Doppler radar.The error of single-Doppler retrieval by using velocity azimuth processing(VAP)technique de-pends on the angle between the directions of wind and the radar beam.Generally,the winds retrieved from single Doppl-er radar are close to those retrieved from dual-Doppler radar.But,the error distribution of the single-Doppler retrievalis different from the dual-Doppler retrieval.We simulate the retrievals of single Doppler observation by the use of theoutput wind data from a 3-D numerical model of severe convection.The comparison of the simulated single-anddual-Doppler retrievals shows that the VAP may be a suitable technique for the operational analysis of mesoscale windfields.It can also be used as a supplement to wind field retrieval in the field experiment.     

RETRIEVAL OF HORIZONTAL WIND PERTURBATION FIELDS FROM SIMULATED SINGLE DOPPLER RADAR OBSERVATIONS

The application of the single Doppler radar dataset analysis is usually confined to the assumption that the actualwind is linearly distributed or uniform locally.Following some dynamic features of convective weather,a conceptualmodel of moderate complexity is constructed,wherewith a horizontal wind perturbation field is retrieved directly fromthe single Doppler radar measurements.The numerical experiments are based on a 3-D cloud model-generatedconvective cell,whose radial velocity component is taken as the radar observations that are put into the closed equationsbased on the conceptual model to retrieve the horizontal wind perturbation field.After the initial field is properlytreated,the retrieval equation is solved in terms of the 2-D FFT technique and the sensitivity to noise is examined.Finally,contrast analysis is done of the retrieved and the cloud model output wind fields,indicating the usefulness of theapproach proposed in this paper.     

单多普勒雷达径向风场反演散度场的一种新方法

为利用多普勒雷达的径向风速获得实际风场的信息,提出了一种由单多普勒雷达径向风场反演水平散度场的新方法。在二维平面内,以某个探测点为中心,建立一个分析面,在假设风场呈线性变化的前提下,直接由径向风速推导出此探测点的散度值。并对几种典型理想风场的散度场进行了反演试验,试验结果表明,反演的散度场与分析的散度场比较一致。并对反演场与分析场之间的差别进行了讨论。     

以单多普勒雷达观测资料反演冷锋流场的试验

通过对一次欧洲冷锋过程单多普勒雷达立体扫描资料的实例计算来考察用ＶＡＤ（ＶｅｌｏｃｉｔｙＡｚｉｍｕｔｈＤｉｓｐｌａｙ）方法反演锋面在垂直剖面图上的风场和用ＶＡＰ（ＶｅｌｏｃｉｔｙＡｚｉｍｕｔｈＰｒｏｃｅｓｓｉｎｇ）方法反演水平风场的可能性。反演结果不仅显著展示了锋面两侧的风向切变，而且也展示出气团内部风场中存在的中尺度结构。由于ＶＡＰ方法对距离圈上多普勒速度随方位的变化非常敏感（多普勒速度的脉动）     

双多普勒天气雷达联合探测大气风场技术进展

本文详细总结了目前国内外关于双多普勒天气雷达联合探测大气风场的技术和发展动态，阐述了双多普勒天气雷达联合探测大气风场技术方法的发展进程和几种探测方法的优缺点。从中可以了解到目前双多普勒天气雷达联合探测大气风场的最新技术——综合和连续调整技术。     

RETRIEVAL OF HORIZONTAL WIND PERTURBATION FIELDS FROM SIMULATED SINGLE DOPPLER RADAR OBSERVATIONS*

The application of the single Doppler radar dataset analysis is usually confined to the assumption that the actual wind is linearly distributed or uniform locally.Following some dynamic features of convective weather,a conceptual model of moderate complexity is constructed,wherewith a horizontal wind perturbation field is retrieved directly from the single Doppler radar measurements.The numerical experiments are based on a 3-D cloud model-generated convective cell,whose radial velocity component is taken as the radar observations that are put into the closed equations based on the conceptual model to retrieve the horizontal wind perturbation field.After the initial field is properly treated,the retrieval equation is solved in terms of the 2-D FFT technique and the sensitivity to noise is examined.Finally,contrast analysis is done of the retrieved and the cloud model output wind fields,indicating the usefulness of the approach proposed in this paper.     

民航上海多普勒雷达风场反演UW方法的试验

介绍一种实用的单多普勒雷达风场反演方法－UW技术，并以民航上海气象中心多普勒雷达资料的试验结果作简单验证。     

MODELING AND QUANTITATIVE RETRIEVAL OF FINITE FIELD FOR THE TROPICAL SEA SURFACE WIND SPEED OF THE FY-3B MICROWAVE IMAGER

The purpose of this study is to select a suitable sea wind retrieval method for FY-3B(MWRI). Based on the traditional empirical model of retrieving sea surface wind speed, and in the case of small sample size of FY-3B satellite load regression analysis, this paper analyzes the channel differences between the FY-3B satellite microwave radiation imager(MWRI) and TMI onboard the TRMM. The paper also analyzes the influence of these differences on the channel in terms of receiving temperature, including channel frequency, sensitivity and scaling precision. Then, the limited range of new model coefficient regression analysis is determined(in which the channel range settings include the information and features of channel differences), the regression methods of the finite field are proposed, and the empirical model of wind speed retrieval applicable to MWRI is obtained, which achieves robust results. Compared to the TAO buoy data, the mean deviation of the new model is 0.4 m/s, and the standard deviation is 1.2 m/s. In addition,the schematic diagram of the tropical sea surface wind speed retrieval is provided.