基于概率分布模型的北京地区冰雹灾害风险区划

利用北京地区20个地面气象台站1951-2006年的冰雹数据,统计分析了各台站冰雹日数在作物生长季4-10月的不同月份及年度发生的风险概率特征,并在此基础上进行了北京地区不同时段不同雹日数的冰雹风险区划.结果表明:北京地区各台站雹日数在不同时段的发生具有明显的POSSION分布特点;从年度分布来看,风险概率随着年雹日的增多逐渐降低,各台站年雹日≥1、2、3、4 d的风险概率分别在50%、18.8%、4.6% 和0.9%以上.从空间来看,北京地区冰雹风险具有明显的山区高于城区的空间分布特征,山区又以西北部最大、东部和西部次之、南部最小;西北部山区佛爷顶附近冰雹年发生概率高达98.1%,6月冰雹风险概率也在60%以上,是北京地区冰雹的主灾区.

Hail risk distribution based on probability density model in Beijing region

Based on data from 20 meteorological stations in Beijing region between 1951 and 2006,risk distribution maps of hail disaster in Beijing region were made after probability density functions were determined.The results showed that hail disaster has marked characteristics of POSSION distribution.Risk of hail disaster reduced along with the increasing hail days in a year.The hail risk probabilities are 50 percent,18.8 percent,4.6 percent and 0.9 percent respectively while the hail days are no less than 1,2,3 and 4 in a year.Hail risk distribution presents marked spatial characteristics in Beijing.Spatially,the high-frequency hail disaster occurred mainly in mountainous areas rather than urban areas.The northeastern part is much more likely to have hail storms than the southern area.The hail risk probability of Fuyeding station in northwestern part is 98.1 percent in a year and over 60 percent in June.it is the main disaster district in Beijing.