基于指标叠套法的安徽省强对流天气潜势预警研究

Study on potential warning of severe convective weather based on method of overlapping sets of indices in Anhui province,China

对2005—2007年4—9月安徽省冰雹、雷雨大风等强对流天气日数进行统计,分析了基于探空资料计算的不稳定指标与强对流天气发生的关系。结果表明:K指数、A指数、沙氏指数和对流有效位能、归一化对流有效位能和对流抑制能量这几个指标对于强对流天气指示意义较好。基于此结果,挑选K指数、沙氏指数和对流有效位能针对不同季节划分阈值,建立强对流天气潜势预警指标,并利用中尺度模式MM5的数值预报产品计算该指标,对2005—2010年13个强对流天气过程预报结果进行对比检验表明,MM5模式给出的强对流天气潜势预警产品对大多数过程均能起到预警作用。对其中两次强对流天气过程分析表明,模式具备预报强对流发生潜势的能力,预报结果对强对流天气发生的时间、落区有预警意义。

A number of days of severe convective weather during April to September from 2005 to 2007 in Anhui province were analyzed, and relationships between the severe convective weather and instability index calculated by sounding data were investigated. The results show that K, A, Si indices, convective available potential energy （CAPE）, normalization convective available potential energy （NCAPE） and convective inhibition （CIN） are in- dicative of severe convective weather. Thus, the potential warning indices of severe convective weather are established,including K index and Si index as well as CAPE. According to these indices, the threshold values in the different seasons are determined. These indices are calculated by the products of MM5 mesoscale model. 13 severe convective weather processes from 2005 to 2010 are predicted by the MM5 model. Compared with the real situa- tion, warning products from the MM5 model are predictive to most of the cases. Among cases, two severe convective weather processes are analyzed in detail. It indicates that the MM5 mesoscale model could predict the potential of severe convective weather, especially for the time and location of the occurrence of severe convective weather.