2016-2020年中国龙卷过程和灾情特征

TORNADOES IN CHINA AND THEIR DISASTER CHARACTERISTICS FROM 2016 TO 2020

基于2016—2020年收集的龙卷个例及详细的龙卷灾情调查资料,根据“增强藤田级别”分类标准和中国龙卷强度等级行业标准,对中国龙卷过程和灾情特征进行了分析总结。(1)近5年共收集了我国178个龙卷个例,EF2级及以上的强龙卷漏记情况相对较少,比较接近实际发生的情况,EF1级及以下的弱龙卷因灾情小可能被忽略,因此龙卷统计总数量可能会被明显低估。龙卷主要发生在中国东部和部分中部地势平坦的地区,青藏高原、云南等地区也有弱龙卷发生,广东省、江苏省和安徽省是龙卷发生频次最多的三个省份。95%的龙卷发生在地面粗糙度长度为0.04~1.70m的地区,该粗糙度长度范围下垫面土地利用类型为低矮作物、农田、郊区、矮树丛及低矮建筑为主。96%的龙卷发生在4—9月,集中在白天10—20时。(2)基于39个有详细灾情调查的龙卷个例,共确认的EF2级(含)以上强龙卷22个,比1961—2010年每5年平均次数多5.5个,其中EF3级龙卷5个,EF4级龙卷3个,龙卷路径长度和宽度与龙卷强度呈正相关。(3)中国龙卷的地面灾情特征包括:狭长的路径和龙卷条迹、辐合状倒伏、扭曲状折断、强度等级非对称分布、抛射物明显等。(4)龙卷的实拍视频展示了龙卷发展不同阶段的形态特征,在国内第一次通过龙卷实拍视频和现场灾情特征确认了我国有多涡旋龙卷发生的事实,为龙卷的组织和演变研究提供了珍贵的数据。

Based on the data of tornadoes that happened during 2016—2020 and corresponding damage survey data,the present study analyzed the characteristics of tornadoes in China according to the“Enhanced Fujita scale”and the tornado intensity scale proposed by Chinese meteorologists.The main conclusions are as follows:(1)In the past 5 years,we collected 178 tornadoes cases in China.Few EF2 tornadoes or stronger ones were overlooked,which is close to the actual situation;however,EF1 tornadoes and weaker ones may be ignored,so the total number of tornadoes may be significantly underestimated.Tornadoes mainly occurred in the flat areas in eastern China and parts of central China.Weak tornadoes also occurred in the Qinghai-Tibet Plateau and Yunnan Province.Guangdong Province,Jiangsu Province and Anhui Province were the three provinces with the highest frequency of tornado occurrence.95%of the tornadoes occurred in the areas with a surface roughness length of 0.04~1.70 m,and the underlying land within these areas were mainly used for low-rise crops,farmland,suburbs,bushes,and low-rise buildings.96%of the tornadoes occurred during 10:00—20:00 BJT from April to September.(2)Based on 39 cases of tornadoes with detailed damage survey,a total of 22 strong tornadoes were confirmed at or above the EF2 scale,5.5 more than the average number of times every 5 years from 1961 to 2010,among which 5 were EF3 tornadoes,3 were EF4 tornadoes,and the length and width of the tornadoes path were positively correlated with the strength of the tornado.(3)The ground disaster characteristics of tornadoes in China include:narrow path and strip traces,convergence-like inversion,twisted break,asymmetrical distribution of intensity,obvious projectiles,etc.(4)The live video of the tornado showed the morphological characteristics of the different stages of the development of tornadoes,and for the first time in China,the fact that there are many vortex tornadoes was confirmed,providing valuable data of the structure and evolution of tornadoes.