深圳云地闪时空分布特征研究

利用1997-2011年云地闪电定位探测资料和深圳国家基本气象站1953-2011年的观测资料，对深圳云地闪电（简称地闪）时空分布特征和雷暴日变化趋势进行分析。结果表明：深圳雷暴日数近59 a来呈下降趋势，小波分析显示年雷暴日数存在5 a周期和10-15 a的次周期；年内地闪频次特征表现为6月和8月双峰形特征，8月为全年地闪次数最多的月份；雷暴的活跃程度与太阳辐射热力条件密切相关，地闪活动高峰出现在14-18时；深圳地闪密度呈现西北多、东南少，内陆地区多、沿江沿海地区少的分布特征，地形、海陆分布是影响地闪空间分布的重要原因；地闪强度的分析表明，正、负闪月平均强度峰值分别出现在2月和6月，负闪强度低于正闪，正、负闪日强度峰值均未出现在频次峰值时段。

Temporal and spatial distributions of cloud-to-ground lightning in Shenzhen

Based on the cloud-to-ground lightning data from the detecting station during 1997 to 2011 and the observational data from the national basic weather station at Shenzhen during 1953 to 2011,the temporal and spatial distributions of cloud-to-ground lightning flashes （hereafter abbreviated as lightning flashes） and the trends of thunderstorm days in Shenzhen were analyzed.The results show that the annual thunderstorm day is in a descending trend in recent 59 years,and it is a 5 years main cycle and a 10-15 years sub-cycle by a wavelet analysis.The significant peak values of the monthly thunderstorm days occur in June and August,especially in August.There is a close relation between activity of thunderstorm and solar radiation.The frequency of lightning flashes is highest from 14：00 to 18：00 at Shenzhen.Many lightning flashes are recorded in the northwestern area and inland area,while the few are in the southeastern area and coastal or riverside area in Shenzhen.The spatial distribution of lightning flashes is significantly influenced by the land-sea distribution and the topography.The analysis of the lightning intensity shows that the positive and negative peak values of mean monthly lightning intensity appear in February and June respectively,and the intensity of the negative lightning is lower than that of positive lightning flashes.Neither the positive lightning nor the negative lightning flashes,they never occur in the time period that the frequency of lightning flashes is the highest.