江苏省苏北地区季节性干旱特征及动态风险评价研究

摘要

利用江苏省统计年鉴提供的气象资料，通过标准化降水指数（SPI）计算苏北地区近25 a（1989—2013年）的季节干旱指标，分析江苏省苏北地区五市的季节性干旱时空特征和发生规律，并对其进行动态干旱风险评价。基于危险性、脆弱性、暴露性和防灾减灾能力这四个影响因子构建相应干旱风险评价指标体系，选取适合苏北五市的气象、水文、地理、社会经济方面相关二级指标，组合运用熵权法和 CRITIC 法确定各指标综合权重，通过加权综合评价法对苏北五市进行动态旱灾风险评价。结果表明：苏北地区干旱时间特征存在明显的季节性差异，发生干旱多为轻旱和中旱，且多发生于春夏秋三季，盐城市冬季发生中旱和重旱相对较频繁；干旱强度变化趋势和干旱频率趋势大体一致，五市发生春旱的频数和强度总体都呈增加趋势，而秋季情况略有好转。近年来，苏北地区五市的旱灾风险具有一定的稳定性，风险排名依次为：淮安＞连云港＞宿迁＞徐州＞盐城，其中，防灾减灾能力对于干旱风险的动态变化体现出较强相关性。%According to the meteorological data provided by Jiangsu statistical yearbook ,through the standardized precipitation index (SPI) ,this paper calculated the seasonal drought indexes of five cities in northern Jiangsu Province in recent 25 years (1989 — 2013) in order to analyze the spatial-temporal characteristics and occurrence regularity of drought ,and to assess dynamic drought risk .Based on four risk factors including dangerousness risk ,exposure risk ,vul-nerability risk and disaster prevention and mitigation capacity ,the paper selected ten suitable indexes covering meteoro-logical ,hydrological ,geographical ,social and economic aspects to build a corresponding drought risk evaluation index system .After a combination use of entropy method and the CRITIC method to determine the weight of each index , weighted dynamic risk evaluation method was used to calculate the drought risk score of every city from 2008 to 2013 . The results showed that drought in northern Jiangsu Province possessed obvious seasonal differences .Light drought and medium drought usually occurred in the spring ,summer and autumn ,while heavy drought and excessive drought occurred most often in autumn and winter in Yancheng city .The tendency of drought intensity was generally consistent with the tendency of drought frequency .Drought frequencies and intensities in the five cities were generally increased in spring , while the situation slightly turned better in autumn .In recent years ,drought risks of the five cities had a certain kind of stability and their risks rankings from high to low were :Huaian > Lianyungang > Suqian > Xuzhou > Yancheng .In addi-tion ,there was a strong agreement between the disaster prevention and mitigation capacity ,and the dynamic changes of drought risk .