保定地区冰雹的气候及物理量参数特征

利用保定地区1974~2010年4~10月19个县市气象站冰雹资料,对保定地区近37 a的冰雹气候特征进行了详细统计与研究,在此基础上筛选出典型个例,并基于北京和邢台探空站2000~2010年探空资料,细致分析了典型冰雹日常用物理量参数的阈值。结果表明:保定地区年均冰雹日数的地区差异较大,年均最大降雹日数中心位于西北部山区的涞源,铁路线以西年均降雹日总体多于铁路线以东各市县;冰雹日数与海拔高度呈显著正相关,相关系数达0.924;冰雹日数夏季最多、春季次之、秋季最少,其中6月冰雹出现几率最大;近37 a来,保定地区年冰雹日数均呈不同程度的减少趋势,其中西部山区减少趋势及波动最明显,说明降雹频繁的地区降雹年际波动也大;各物理量参数的阈值可作为预报本市冰雹的参考。

Climatology and Physical Parameters Characteristics of Hail in Baoding

Based on the data of hail days at 19 meteorological stations in Baoding from April to September during 1974-2010,the cli-matology characteristic of hail was studied,firstly.Then,ten typical cases of hail were selected.And on this basis the physical param-eters characteristic of hail in typical hail days were analyzed in detail using the sounding data at Beijing and Xingtai stations during 2000-2010.The results displayed that the spatial distribution of annual mean hail days were obviously different during 1974-2010 in Baoding area.The hail days reduced from northwest to southeast in Baoding.The maximum value of annual hail days occurred in Laiyuan which located in the mountain region of northwest Baoding,and the annual hail days in the west side of the rail line were gen-erally larger than that in the east side.The correlation between the hail days and the altitude was significantly positive,and the correla-tion coefficient was 0.924.The hail days were the most in summer,the next in spring,and the least in autumn,and the accumulative hail days in June were the most,and reached 189-day from 1974-2010.In the past 37 years,the annual hail days in Baoding had decreasing trend to a different extent,while the decrease and fluctuation of hail days in the mountain region of north Baoding was signif-icant.Furthermore,the thresholds of physical parameters could be used as forecast indexes for the hail in Baoding.