江苏省典型年梅雨洪涝灾害对比分析

Contrastive analysis of plum rains floods in typical years in Jiangsu Province

梅雨期降水形成的洪涝和枯梅年产生的干旱是江苏省主要的气象灾害。为了能客观地划分各年梅雨的旱涝等级,从而为防灾减灾决策提供依据,利用江苏省近50年来的梅雨资料,考虑梅期持时长短、梅期平均日雨量及暴雨日数等3个因子,给出了梅雨强度计算模型及梅期旱涝指标,较好地反映了江苏省每年各地的梅期旱涝状况。结合实际灾情,确定了典型梅雨洪涝年的标准。针对1954,1991和2003年3个比较典型的梅雨洪涝年,进行了详细的比较分析,结果表明:(1)长江及淮河流域上游的客水、入梅之前的降水量和梅期降水会直接影响该省梅雨期的洪涝灾情;(2)1991年的洪涝是历年来最为严重的,1954年的洪涝稍重于2003年;(3)3个典型梅雨洪涝年中全省最涝的地区都位于沿淮地区或江淮之间地区的北部,淮北地区这3年中都出现了较重的涝灾,淮北南部的灾情重于北部。

Floods and droughts caused by excessive or insufficient precipitation in plum rains period are the primary meteorological disasters in Jiangsu Province.In order to grade annual floods/droughts objectively and to provide bases for making decisions on defending and reducing disasters,a model of calculating the intensity of plum rains and assessing the indexes of droughts/floods is proposed in this paper,based on the data of plum rain in recent 50 years in Jiangsu Province.Plum rain's duration,average rainfall and days of rainstorm are considered.This model reflects the fact of annual floods/droughts in each area better.According to the situation of disasters,standards of typical flood-years caused by plum rain are defined and detailed contrastive analyses of three typical flood-years-AD1954,1991,2003 are given.The results show that:(1)The droughts/floods in Jiangsu may be affected directly by upriver water of Changjiang River and Huaihe Rivers,rainfall before plum rains begining and rainfalls in the whole plum rains period;(2)In recent 50 years,the flood in 1991 is the most severe and the flood in 1954 is more severe slightly than that in 2003.(3)The most severe floods areas are along Huaihe Rivers or in the northern part of the area between Changjiang River and Huaihe Rivers in the above mentioned three typical flood-years,severe floods also occurred in Huaibei at the same term,and the floods in southern part of Huaibei are more severe than that in northern part.