鲁西南地区云地闪密度历史平均值研究

Study on the Historical Averaged Cloud-to-Ground Lightning Flashes Density in Southwest Shandong Province

为了计算鲁西南地区年云地闪密度的历史平均值,选取雷暴日数据及闪电日数据进行相关性分析,将雷暴日与可闻范围内云地闪密度进行拟合,并进一步进行分组拟合,分析相对误差,最后绘制出鲁西南地区云地闪密度历史平均值分布图。结果表明:在距离观测台站6~22 km范围内,雷暴日与闪电日密切相关,两者的相关系数在距离观测站不同半径范围内呈单峰状分布,确定雷声可闻距离为14 km;雷暴日与云地闪密度拟合得出的关系式优于规范公式,更能代表云地闪密度历史平均值,且具有相同成雷机制的邻近区域,由雷暴日通过拟合公式计算得到的云地闪密度与实际发生的云地闪密度一致性更好;云地闪密度历史平均值总体呈现出西南、东北大,中间小的漏斗形,区域差异明显。

In order to calculate the historical average annual cloud-to-ground lightning flashes density in the southwest of Shandong Province,the correlation between thunderstorm days and lightning days was analyzed firstly,then the thunderstorm days and cloud-to-ground lightning flashes density within audible range were fitted and carried on further based on group,and the relative errors were analyzed. Finally,the spatial distribution of historical averaged cloud-ground lightning density was drawn in the southwest of Shandong Province. The results show that the thunderstorm days were closely related to the lightning days within distances of 6-22 km from the meteorological stations,and the correlation coefficients of them presented a single peak curve within different radius of the observatory,the audible range of thunder was 14 km. The fitting result between thunderstorm days and cloud-ground lightning density was superior to the normal formula,and it was more representative of the historical average annual cloud-to-ground lightning flashes density. The adjacent area with the same mechanism for thunderstorm,cloud-to-ground lightning flashes density calculated by the fitting formula by using thunderstorm days was consistent with the actual values. The historical average cloud-ground lightning density presented a funnel-shape with high values in the southwest and northeast and low values in the middle,and the regional difference was significant.