不同测站数量和组合对广域雷电定位精度的影响研究

Effect of Number and Configuration of Participating Stations on Lightning Location Accuracy for the Long-Range Lightning Network

摘要: 本文研究了不同测站数量和不同组合对VLF/LF广域雷电定位网定位精度的影响，分别以10站、11站、12站和13站的同步定位结果为参考点，分别选取了其中的5~9站同步、5~10站同步、5~11站同步和5~12站同步的任意测站数量和不同组合进行了重新定位，研究了这种相对定位偏差的变化规律。结果表明：1) 在测站网的外围区域，不同测站数量和不同组合的定位结果通常呈现近似的一条线，相对定位偏差很大，平均偏差可达几十公里；而在测站网内部，这种相对偏差较小，平均偏差为几公里。2) 无论是测站网内部还是外部，利用变速度定位算法时，不同测站和数量的定位结果相对比较集中，而利用恒定光速的定位结果比较分散，表明变速度定位方法更优、不同测站数量和组合的影响较小。3) 当测站数量超过10个时，这种测站基线长度可达上千公里的甚低频段的广域雷电探测网的定位结果基本趋于恒定；如果以10个及以上的同步测站的定位结果为参考点，则其中任意6~7个同步测站的相对定位偏差基本处于5 km以内。

Abstract: The effect of the number and configuration of participating stations on lightning location accuracy have been studied for the Very Low Frequency Long-range Lightning Location Network (VLF-LLN). Firstly, the lightning flashes located by the 10-station,11-station,12-station and 13-station synchronized waveform data are chosen as the reference value, respectively, and then the relative location deviation distance have been evaluated for different number of participating stations and its configuration from 5 to 9, 5 to 10, 5 to 11 and 5 to 12, respectively. 1) It is found that effect of the number and configuration of participating stations on lightning location is much more outside of the network than that inside the network, and the relative deviation distance decreases with the increase of number of stations and the spatial distribution of the location results outside the network approximately seems to be on a straight line. Outside the network, the average relative location deviation is about tens of hundreds km, while it is only several km inside the network. 2) We have compared with the location results by using the assumed light speed (c) of lightning-radiated sferic from the lightning stroke point to the observation station and the equivalent propagation method (v), and it is found that the effect of the number and configuration of participating stations on lightning location deviation is much more for the assumed light speed (c) than that for the variable propagation (v), which means that the equivalent propagation method (v) is more reasonable. 3) For the VLF-LLN with the baseline length of several thousands of km, the lightning flashes located by the synchronous 10-station and more seem to be a constant range value, and if we choose the lightning flashes located by the 10-station,11-station,12-station and 13-station synchronized waveform data as the reference value, respectively, the location deviation distance are statistically approaching to be within 5 km.