基于人工引雷的粤港澳闪电定位系统性能评估

利用2014—2019年中国气象局雷电野外科学试验基地广州从化人工触发闪电试验所获资料，评估粤港澳闪电定位系统(Guangdong-Hongkong-Macau Lightning Location System，GHMLLS)性能，结果表明:GHMLLS对人工触发闪电和回击的探测效率分别为96%(48/50)和88%(233/265)，回击位置定位误差的算术平均值、几何平均值和中值分别为279 m，193 m和202 m。对于触发闪电的回击过程，GHMLLS探测的回击电流峰值(I_LLS)全部偏低，与通道底部雷电流峰值的直接测量结果(I_DM)相比，I_LLS的相对偏差平均值(中值)为-37%(-36%)，但I_LLS和I_DM相关系数为0.93，存在显著正相关关系(达到0.01显著性水平)；截距为0的线性拟合结果表明I_LLS与I_DM存在65%的比例关系，利用该系数校正I_LLS，结果的相对偏差绝对值的平均值(中值)为15%(12%)。GHMLLS有对应定位记录的233次触发闪电回击中，16次定位结果为云闪，判别正确率为93%。被误判为云闪的回击的I_DM更低，可用于定位的站点数量更少，定位误差更大，I_LLS的精度更低。

Evaluation of GHMLLS Performance Characteristics Based on Observations of Artificially Triggered Lightning

Artificially triggered lightning refers to the lightning that is artificially triggered to the ground under appropriate thunderstorm conditions. The location of artificially triggered lightning can be determined; the occurring time can be precisely stamped, and the channel-base current can be measured directly. Therefore, it's one of the effective methods to evaluate the performance of lightning location system (LLS). From the observations of artificially triggered lightning experiment conducted at the Field Experiment Base on Lightning Sciences, China Meteorological Administration from 2014 to 2019, 50 lightning flashes are selected to evaluate and analyze the performance characteristics of Guangdong-Hongkong-Macau Lightning Location System (GHMLLS).The results show that the lightning detection efficiency and stroke detection efficiency are about 96% (48/50) and 88% (233/265), respectively. The arithmetic mean, geometric mean and median values of location error are 279 m, 193 m and 202 m, respectively. The results show that there is a systematic deviation to the southwest in GHMLLS observations around the triggered lightning experiment site, which is about 170 m to the west and 50 m to the south. After correction, the arithmetic mean, geometric mean and median values of location error are reduced to 198 m, 108 m and 103 m, respectively. The linear fitting result with intercept of 0 shows that the LLS-inferred peak current of GHMLLS is about 65% of the direct measurement value of the channel-base current. Meanwhile, the arithmetic mean (median) value of the LLS-inferred peak current error is -37% (-36%). However, there is a strong positive correlation and the correlation coefficient is 0.93. The arithmetic mean (median) value of the absolute value of the LLS-inferred peak current error is reduced to 15% (12%) when the ratio of 65% is used to correct them. Among 233 return strokes of triggered lightning flashes, 16 return strokes are mistakenly classified as intra-cloud lightning, so the return stroke classification accuracy of GHMLLS is 93%. The peak currents of these mistakenly classified return strokes are lower, the stations available for locating are fewer, and the errors of location and LLS-inferred peak current are larger.In conclusion, GHMLLS have good detection efficiency and location accuracy. The return stroke classification accuracy of GHMLLS is at a high level as well. Nevertheless, there is an obvious systematic deviation in the LLS-inferred peak current of GHMLLS. In order to obtain more reliable analysis results, it's recommended to divide it by 0.65 when using the LLS-inferred peak current of GHMLLS.