海南岛地闪活动的时空特征与海陆风关系

The Relationship of Temporal and Spatial Characteristics of Lightning Activities over Hainan Island and Sea-Land Breeze

海陆风是触发海南岛春夏季节对流天气的主要因素,对海南岛闪电活动有很大影响。利用2007—2008年以及2013年海南省气象局地闪定位监测网资料、中尺度气象自动站逐时地面风向风速等数据,采用统计分析方法,研究海南岛地闪活动的时空分布特征及海陆风对其影响。结果表明:海南岛地闪主要发生在春夏季,大部分地区地闪主要发生在白天,特别是下午,而南部沿海和西部沿海地区的地闪在夜间较白天更为活跃。春夏季活跃的海陆风对海南岛地闪活动有很大影响,是导致海南岛地闪具有时间和空间分布特征的主要原因之一:在西北部内陆和东北部沿海地区,白天偏北海风与环境偏南风辐合,造成地闪活动多发生在白天;而在南部沿海地区,夜间偏北陆风常和环境偏南风辐合造成地闪在半夜和早晨更为活跃。

Sea-land breeze is one of the main triggers of convective weather during spring and summer in Hainan Island.To better understand the relationship between sea-land breeze and lightning activities over Hainan Island,and therefore to improve the prediction capability of lightning activities over Hainan Island,based on the lightning data from Lightning Location Monitoring Network and hourly surface wind direction and wind speed data from mesoscale automatic weather stations of Hainan Meteorological Service,the relationship of temporal and spatial characteristics of lightning activities over Hainan Island and sealand breeze was studied using statistical method.Result shows that the lightning mainly occurs in spring and summer over Hainan Island.In most areas,lightning occurs during the daytime,especially during the afternoon.On the southern and western coasts,lightning is more active during the nighttime than the daytime.Result also indicates that,in spring and summer,the active sea-land breeze has a key impact of lightning activity and is likely one of the important reasons led to the temporal and spatial distribution characteristics of lightning activities over Hainan Island.Over the northwest inland and the northeast coastal areas,the northerly sea-breeze converges with the southerly environmental wind during the daytime,resulting in more lightning activities during the daytime.Over the southern coastal areas,lightning is more active during the middle of the night and the morning due to the convergence of the northerly land-breeze and the southerly environmental wind.