二维多路多普勒雷达风场自动退模糊算法应用研究

Application study of automated 2D multipass Doppler radar velocity dealiasing scheme

本文选取Zhang Jian的二维多路自动退模糊算法做雷达径向速度退模糊应用研究,并做适当改进。它首先通过在一个仰角扫描数据中搜寻速度线附近的弱风区来确定初始参考点集,并对弱风区内三条邻近的径线进行连续性检测和模糊订正,然后从顺时针和逆时针两个方向进行两轮二维退模糊处理。改进后,在第一轮和第二轮二维退模糊过程中,先不在切向上对可疑模糊点进行订正,而是根据空间连续性原则,在切向上确定更多的非模糊点作为参考速度,然后在从径向上进行退模糊处理,这样可以有效避免了在真实的切变(辐合)区造成不恰当的模糊订正。对台风、龙卷、飑线等系统中的速度模糊订正试验结果表明,该算法退模糊的准确率高,在雷达观测资料无效点较多的情况下,该技术退模糊效果比WSR-98D更优,更加有利于实际业务运行和科研分析。

Based on Zhang Jian＇s automated Two-Dimensional Multipass velocity dealiasing scheme, this study makes some modifications to improve its performance in strong shear regions. The automated dealizsing can be used to first identify a set of ＂good＂ gates and radials as initial reference velosity by finding the weakest wind region, and then check continuities among the adjacent three radials and correct the velocity which is identified as aliased. After that, the scheme goes to two rounds Two-Dimensional dealiasing from both clockwise and counterdockwise. Difference to Zhang＇s Jian scheme which correct all the suspectable gates in last two round along both radial and azimuth directions to gain more ＂good＂ gates; it deals with all the gates in question radially. The test results for typhoon, tornado, severe thun- derstorm situations show that the new alogrithm is very robust and efficient. Compared with the current WSR-98D operational velocity dealiasing scheine, it shows improvements in case of many data voids.