乌鲁木齐地区山体地形对地闪回击定位精度的影响

Effect of Mountain Terrain on Lightning Return Strokes Location Accuracy in Urumqi

利用二维时域有限差分算法(FDTD),构建了真实地形下的雷电电磁波传播模型,研究了乌鲁木齐周边区域山地地形对雷电电磁波传播的影响,然后提出了一种修正闪电定位误差的方法即不同步长的地形包络法。模拟结果表明:1)山地地形会明显改变切向磁场的波形峰值大小和上升沿时间,给闪电定位带来误差,波形峰值变化最大的增加了57%,上升沿时间增加范围在1~5μs,相比平地最大定位误差增加了3 800 m。2)步长为10 km的地形包络法修正效果最好,最大修正了510 m的定位误差。

Using the two-dimensional time-domain finite difference algorithm(FDTD), a lightning electromagnetic wave propagation model under real terrain was constructed, the influence of mountain terrain on the electromagnetic wave propagation in the surrounding area of Urumqi was studied, and then a method to correct lightning location error was proposed, that is terrain envelope method with different resolution. The simulation results show that: 1) Mountain terrain will obviously change the peak value of the tangential magnetic field and the rising edge time, which will bring errors to the lightning location. The peak value of the waveform changes by a maximum of 57%, and the rising edge time increases in the range of 1~5 μs. Compared with flat ground, the maximum location error is increased by 3 800 m. 2) The terrain envelope method with a resolution of 10 km has the best correction effect, and the maximum of corrected location error is more than 510 m.