核电站周边地区龙卷风时间分布与灾害特征

通过气象站记录、灾害大典、气候影响评价等多种途径，收集到湖北通山核电站周边300km×300km区域范围内1956-2000年龙卷风资料，对龙卷风的时间分布和灾害特征进行了分析。结果表明：龙卷风有明显的时间分布，一年中主要集中在夏春季，以7月、4月最多；一天中，午后至傍晚最多；龙卷风平均持续时间为17min；近45年，1976～1985年这10年中龙卷风出现最频繁；龙卷风出现时，蒲福风力等级一般在10级以上，平均12～13级，最大17级，富士达风力等级平均F1级，最大F3级，风速约70m·s^-1；龙卷风从NW→SE向移动的频次最多；龙卷风影响宽度一般在0．5km内，平均带长为10．0km；龙卷风灾害呈并发性，主要是风灾，往往伴有冰雹、暴雨、雷击及飞射物，使灾害加重。

Research on Characteristics of Disasters and Temporal Distribution of the Tornadoes Around the Nuclear Power Plant in Tongshan,Hubei

The characteristics of disasters and temporal distribution of the tornado events is analyzed based on the primary data collected from the area of 300 km×300 km around the nuclear power plant in Tongshan, Hubei from 1956 to 2000 by many ways such as the record in meteorological stations, the collection of disaster events, the report of climate impact assessment. It is revealed that： （1） there is apparent temporal （daily, monthly, decadal） distribution for those tornado events, mostly concentrated in summer and spring especially in July and April in a year, from mid-day to early evening especially at afternoon for a day, and from 1976 to 1985 the average lasting time for all tornadoes is 17 min; （2） with Beaufort scale, the wind speed grade is mostly over grade-10, the average is grade-12 or grade-13, the strongest can get to grade-17; with Fushida F scale, the average wind speed grade is grade-1, the strongest can get to grade-3 with 70 m·s^-1 or so; （3） the most frequent moving direction of the tornadoes is from NW to SE, and the width of affected belt by the tornadoes is mostly less than 0.5 km, the average length is 10.0 km; （4） there are many kinds of disasters causing by tornadoes, the most severely disaster is made by the extremely strong wind, and the concomitant hailstones,heavy rain,lightning strikes and projectiles can make the disaster heavier.