GVAD技术及其在新一代天气雷达中的应用

摘要

The gradient velocity azimuth display (GVAD) technology has been developed to get over the in-fluence of velocity aliasing in traditional velocity azimuth display (VAD) technology,which can calculate the vertical wind profiler (VWP) above the radar.This paper first introduced the theory of GVAD tech-nology and conducted simulation,and analyzed about the GVAD technology,and then applied it into the case of typhoon and severe precipitation monitored by CINRAD.The simulation result demonstrated that the GVAD technology can overcome the velocity aliasing effectively compared with the traditional VAD technology,and the added noise also can be depressed through low-pass filter.The influence of aliasing ve-locity was got over in the two cases,but the noise and fluctuation in radial velocity were enlarged by the gradient of radial velocity,which affected the retrieval accuracy of wind although the low-pass filter was a-dopted,especially,the retrieval accuracy of wind speed was impacted.In the examples,the retrieved wind speed by GVAD technology was 2-3 m·s-1less than the value by the traditional VAD technology.So,the influence of noise and fluctuation in CINRAD on GVAD technology should be further studied and reduced.%天气雷达中VAD技术可求取雷达站上空水平风垂直廓线,梯度VAD技术(简称GVAD技术)为克服传统VAD技术受速度模糊影响较大而被提出.文中首先从理论上对GVAD技术进行模拟分析,再将其应用于新一代天气雷达实际探测的台风与大范围强降水速度模糊个例,分析其应用效果.理论模拟表明,GVAD技术较传统VAD技术可有效克服速度模糊对反演水平风垂直廓线的影响,加入的模拟噪声,也通过低通滤波方法有效抑制;在两次实际应用个例中,GVAD技术可较好克服速度模糊影响,但方位径向速度中的小波动或者噪声会在径向速度方位梯度中放大,尽管利用低通滤波进行了平滑,但其对反演水平风精度有较大影响,尤其影响水平风速反演精度,在个例中GVAD技术反演风速较传统VAD技术平均偏弱2~3 m·s-1,模拟部分方位缺失并不影响GVAD技术的反演精度.需进一步研究减少新一代天气雷达径向速度资料中小波动或者噪声对GVAD技术应用影响的方法.