朝鲜冰雹的气候特征分析

利用朝鲜1981-2010 年95 个地面观测站的冰雹观测记录, 分析朝鲜冰雹的气候特征。结果表明, 朝鲜的冰雹主要分布在北部山区、中部山区和西部平原地区, 年平均冰雹日数在上述地区分别达到4, 1.5 和1 以上。年平均冰雹日数分布表现出明显的季节变化, 春季主要集中在中部山区和北部山区, 年平均冰雹日数达到0.4; 夏季主要出现在北部山区, 年平均冰雹日数达到0.8; 秋季南移至西部平原和东部沿海地区, 年平均冰雹日数达到0.4。朝鲜的冰雹发生时刻具有明显的日变化特征, 平壤站冰雹最大值出现在13:00LT (当地时)。在研究的时间段内, 朝鲜全国72 个台站的年平均冰雹日数出现显著的下降趋势, 6 个台站的年平均冰雹日数明显上升, 主要分布在北部的两江道。另外, 对平壤观测站的零度层高度(FLH)、归一化对流有效位能(NCAPE)和垂直风切变(VWS)进行分析, 探讨平壤地区冰雹频数下降的原因。

Climatology of Hail in North Korea

The hail climatology in North Korea is analyzed according to the station observation from 1981 to 2010 at 95 weather stations. Geographical distribution of annual hail day (AHD), seasonal variation, diurnal variation, and long-term trend of AHD are discussed. The results show that hail occurs most frequently in the northern mountainous areas, middle mountainous areas and western plains in North Korea. The AHD are 4, 1.5 and 1 days above in these regions. The spring hail falls mainly at middle and northern region, its value is 0.4 day. The summer hail events show high frequency at northern mountain region, and its value is 0.8 day. The autumn hail events often display in western plain and some regions of eastern coast area, and its value is 0.4 day. The diurnal cycle of hail events is distinct, the peek value of hail occurrence is at 13:00LT (local time) at Pyongyang station. During the study period, 72 stations experienced significant decrease in AHD frequency, while only 6 stations that mainly located in Rang Kang Province had distinct increase in AHD frequency. Freezing level height (FLH), normalized convective available potential energy (NCAPE), and vertical wind shear (VWS) derived from sounding data at Pyongyang station are also discussed to understand the decrease trend of AHD in Pyongyang region.