中国典型区域雷电活动气候特征及其机制分析

Characteristics of lightning activities over typical areas of China and analysis of the causes

选取不同纬度不同下垫面的四川省、山东省和黑龙江省,利用2005—2010年地闪资料,研究了三个典型区域雷电活动气候特征及其物理机制。在不同时间尺度上,三省地闪变化呈现不同的年际、月际及日际变化特征。地闪极性上,四川省西部高原及黑龙江省正地闪比例较四川省东部盆地和山东省高,这是由于高海拔、高纬度地区雷暴云顶高度及南北方雷暴云电荷结构差异造成的。地面盛行风系与地形对雷电活动影响很大,迎风坡为雷电活动频发区域,且直接热力环流圈迎风坡地闪比例较间接热力环流圈高。雷电活动具有较大的区域性,其对气温及不稳定参量有较好的响应,雷暴过程中黑龙江省北部对流有效位能(CAPE)及对流抑制能量(CIN)远小于四川省东部及山东省中部,中层相对湿度及700 hPa相当位温四川省东部最大,山东省中部次之,黑龙江省北部最小。

Choosing Sichuan, Shandong and Heilongjiang province located at different latitudes and have different underlying surface, this paper analyzes climatological characteristics of lightning activities and its physical mechanism using CG data 2005--2010. At different time scales, lightning activities in three typical areas showed different inter-annual, monthly and daily variations. As for lightning polarity, the proportion of positive CG lightning in the western highlands of Siehuan province and Heilongjiang province is much more than that in eastern Siehuan Basin and Shandong province, which can be ex- plained by thunderstorm cloud top height and cloud thunderstorm charge structure diversity of different al- titude and latitude. Prevailing winds and surface topography have great impact on lightning activities, windward areas prone to lightning activities, and lightning activities ratio of windward slopes of the directthermal circulation loop is higher than the indirect one. Lightning activities are regional, whose responses to temperature and atmospheric instability parameters are great. In process of thunderstorms, CAPE and CIN in the northern Heilongjiang province are much smaller than that in the eastern Sichuan and central Shandong; the middle-level relative humidity and 700 hPa equivalent potential temperature are the big- gest in eastern Sichuan province, followed by central Shandong province, but the smallest is in the north- ern Heilongjiang province.