大气环流背景下的武当山景区闪电时空分布

Spatio-Temporal Distribution Characteristics of Cloud-to-Ground Lightning in the Wudangshan Mountains Scenic Region in the Background of Atmospheric Circulation

武当山是世界文化与自然遗产,因而武当山风景区的雷电防护尤为重要。截取风景区的地闪数据,以1 km2范围为基本单元,得到各单元内2008-01-01―2011-12-31期间的全部地闪频次、极性、强度等参数,分析武当山风景区雷电环境及武当山地理环境对雷电活动的影响。研究表明:研究区域闪电集中发生在6―8月份的午后T14:00―18:00。闪电频数日变化规律明显,最大值出现在T 16:00,最小值出现在T 10:00―11:00。雷击大地密度整体上随高度表现出明显的增长趋势,雷电流强度平均值与高度大致呈现反向分布趋势,拟合出的雷击大地密度与高度关系式的相关系数R达0.834 56。大气环流特征表明,武当山雷电天气主要有3种类型:副热带高压西北部雷电型、高空槽雷电型和低涡雷电型,其中副热带高压西北部雷电型占主导。

Lightning prevention is particularly important for the Wudangshan Mountains Scenic Region, which has been listed as a site of World Cultural and Natural Heritage. With the range of 1 km2 （1 km ×1 km） being the basic unit, the lightning frequency, polarity, intensity and other parameters in each unit from Jan. 1st, 2008 to Dec. 31st, 2011 are gained for the whole region. At the same time, the influences of geological features and the lightning environment and geographical environment of the Wudangshan Mountains on lightning activities are analyzed. The results show that：most of the lightning happens at T14-18 in June-August. The daily variation of lightning frequency is obvious in each area, the peak appears at T16：00, while the minimum value at T10-11. The lightning frequency increases with the increase of altitude, while the average lightning current intensity decreases in the mountainous areas. As a result, the correlation coefficient between the lightning density and the elevation is 0.834 56. The atmospheric circulation characteristics indicate that there are three main types of lightning storms in the Wudangshan Mountains： there are subtropical high of the northwest lightning type,upper-level trough lightning type and vortex lightning type, in which the northwest lightning type of the subtropical high dominates the area.