关于Doppler雷达VAD技术的讨论

Doppler雷达VAD技术可以从距离圈上的Doppler速度随方位角的分布廓线中提取背景风场的散度。但是，通常Doppler雷达观测到的距离圈上的Doppler速度一般都是不完整的。为了计算散度，必须插补上所有缺侧方位上的Doppler速度，这就使应用VAD技术得到的散度带有不客观的成分。该文利用Doppler速度随方位角的分布具有一阶简谐曲线的特点，提出了用对称法计算散度的方法，从而避免了对Doppler速度方位廓线进行人为插值。文中还针对用VAD技术计算出的不同高度上不同水平面积的散度量级不同的问题，提出了对散度进行面积修正的方法。

A Study of Doppler Radar VAD Technique

Doppler radar VAD technique can draw the divergence of background wind field from the distribution profile of Doppler velocity with azimuth on a distance circle. But, the distribution of Doppler velocity of a distance circle is unintegral normally. In order to calculate the divergence, the data gaps on the velocity-azimuth profile have to be interpolated artificially, which cause the calculated divergence not objective. According to the simple harmonic distribution of Doppler velocity with azimuth, the symmetric method is proposed to avoid making up the data gaps artificially. In addition, the method of area modification for calculating divergence is proposed.