1991-2008年福建省强对流天气特征

利用1991-2008年强对流资料，分析福建省强对流天气时空分布和形成原因以及主导天气型。结果表明：3-6月是福建省强对流天气的高发期，7-8月是次高发期；主要发生在14-20时，且多为孤立日，1-2个站次较为多见。不同季节强对流天气的地理分布有较大差别，春季地域性强，内陆山区明显比沿海多，中北部地区明显比南部多，其他季节分布较为均匀。强对流天气主要发生在强切变类天气形势下，主要出现在春季和秋冬季，其中66.5%的伴有低空西南急流，并以急流适中型和偏北型居多，≥3站次或≥10站次的主导天气形势为低槽型和低涡切变与高空槽配合型；弱切变类强对流天气主要发生在7-9月，主导天气型为副热带高压边缘型和台风外围型。低层无西南急流，发生较大范围强对流天气的可能性小。

Character of severe convection weather from 1991 to 2008 in Fujian province

Based on the meteorological data from 1991 to 2008 in Fujian province, the temporal and spatial distribu- tions of severe convective weather and its formation reason as well as the dominantly synoptic patterns were ana- lyzed. The results indicate that the monthly change of severe convective weather presents a typical bimodal pattern with the higher one from March to June and the other from July to August. A majority of severe convective weath- ers occur during 14：00 to 20：00 and their life time are normally less than one day, and its influencing areas are of- ten within two weather stations. The spatial distributions of severe convective weather in different seasons are dif- ferent. The regional character of severe convective weather in spring is obvious. For example, the most severe con- vective weather events occur in the inland mountain, the middle and north areas rather than in the coastal area and in the south areas. In comparison, the distributions are even in other seasons. Severe convective weather often oc- curs under severe shear weather situation and mainly happens in spring, autumn and winter. The rates of severe convective weather situations accompanying with low-level southwest jets are 66.5%, and the majority are types of moderate or slightly northward jet. The dominant synoptic situations are low trough and low-vortex shear or upper- level trough which influences areas covering more than three stations or ten stations. The severe convective weather of weak shear type often occurs during July to September, and the dominant synoptic patters are subtropical high edge type and typhoon periphery type. There are not southwest jets in low level, so a wide severe convective weather rarely happens.