2013年7月延安暴雨致灾成因与气象服务思考

Causes and Meteorological Services of Rainstorm Disasters in July 2013 in Yan'an

2013年7月陕西延安连续出现5次强降水过程,区域平均降水量是常年同期降水量的近4倍,为延安历史阶段降雨量最多,持续暴雨引发滑塌灾害多点频发,并造成严重人员伤亡、大批革命旧址及珍贵文物受损和严重经济损失。在此对延安7月暴雨过程中的降水特征、致灾成因、预报预警等服务情况进行了剖析、归纳和总结,结果表明,暴雨过程多、累计雨量大、短时降雨强是致灾的主要气象条件;当地地表土质疏松,黄土层遇水易崩解、抗冲抗蚀性弱,居民靠山居住等是主要孕灾条件;在此次暴雨灾害防御中,气象部门预报预警服务及时准确,各级部门采取果断措施及群众自救挽救了大量人员生命及财产损失。

5 consecutive heavy rainfalls hit Yan＇an City,Shaanxi Province in July 2013,the average rainfall of which is nearly four times as much as the average annual precipitation over the same period,which is more than any other recorded meteorological observations.The heavy rainfalls triggered various landslide,resulting in serious casualties,various damage to a large number of precious relics and revolutionary sites,and severe economic losses.This article is mainly about the precipitation characteristics,the causes of disasters,and forecasting and warning services in these rainstorms during this period in Yan＇an.It is found that the high frequency of the heavy rain,the large amount of cumulative rainfall and the large instantaneous rainfall intensity are the major weather conditions of these disasters,while the direct causes of these disasters are listed as follows：Local loose surface loess soil have poor stability and can easily disintegrate when it is infiltrated and eroded by water; Most local residents settled in the foothills.A lot of human life were saved and property damage was reduced in this period because of various efforts,including timely and accurate weather forecasting and warning services provided by meteorological department,decisive measures taken by other relevant departments and self-help activities of the masses.