本計畫屬於一整合型計畫之子計畫。吾人將利用傳統之都卜勒雷達VAD (Velocity Azimuth Display)技術，但將其向下列兩個方向推廣: (1) 傳統之VAD 技術能求出風場、水平輻合/輻散場以及變形場。但結合一回波保守方程後，可再求出渦度場。 (2) 在某特定高度層上，經由計算雷達徑向風沿方位角的梯度以求出風場之垂直剖線。此種推廣可使風場之估計較不受雷達觀測時。徑向風資料被折疊(aliasing)的污染，適合即時作業之要求。上述方法之結果將與雙雷達資料交叉比對以確認其準確度，並經由大量的個案分析統計此風的診斷場與降水強度之關係，並進而發展應用在台灣即時天氣降水預報的技術。 This proposal is part of an integrated project. In this research, the PI will use the traditional Doppler radar VAD technique, but extend its usage in the following two directions: (1) The traditional VAD method derives only the vertical profiles of mean wind, horizontal divergence, as well as horizontal deformation. However, if combined with a reflectivity conservation equation, one can also estimate the parameter of vorticity. (2) By computing the gradients of the radar observed radial velocity with respect to the azimuthal angle, it is also possible to compute the vertical profiles of winds. The advantage of this modification is that the influence of the velocity aliasing to the products can be reduced. This can speed up the computation, and is believed to be useful when the application of VAD method to real-time operations is required. The accuracy of the wind fields derived by the above two methods will be verified by Dual Doppler analyses. It is also planned to conduct a large number of case studies so that the statistical relationship between the diagnostic wind fields and the intensity of the precipitation can be established. Based on this relationship, one can develop the technique used for the nowcasting of Taiwan precipitation. 研究期間：9308 ~ 9407
