变化环境下我国干旱灾害演变趋势分析

Analysis on the evolution trend of drought disaster in China under changing environment

基于1949-2020年全国及各省(自治区、直辖市)作物播种面积、因旱受灾面积、成灾面积及因旱粮食损失量等数据系列,构建了我国干旱灾害综合评价指标系列,分析了我国干旱灾害的时空分布特征及其变化趋势。分析结果表明,时间尺度上,1949-2000年全国干旱受灾率、成灾率和因旱粮食损失率都呈现增加趋势,增加速率分别为1.72%/10 a、1.26%/10 a和0.61%/10 a,而2001-2020年干旱灾害呈逐步减缓趋势。空间分布上,我国北方地区的东北、黄淮海、西北和内蒙古是干旱灾害发生频繁且较为严重的地区,受灾率和成灾率均超过15%和10%;而南方地区的华南、西南和长江中下游受旱成灾相对较轻,受灾率和成灾率低于10%和5%。由干旱灾害综合评价指标分析可得,1949-2020年全国发生重旱以上有26 a,发生特旱有13 a;1980年前发生重旱以上干旱范围的有10个省(自治区、直辖市),1980年以后扩大到了16个,反映出我国是一个干旱灾害多发、频发的国家。气候变暖和人类活动是干旱灾害形成的主要因素,1961-2020年黄淮海、西南等地区年降水量呈减少趋势,1951-2020年中国地表年平均气温呈显著上升趋势,升温速率为0.26℃/10 a;人类活动通过干扰作物的水分收入和支出对干旱灾害形成产生作用,在一定程度上使得干旱灾害更加严峻。

This study analyzed the evolution trend of drought disaster in the whole country and every provinces from 1949to 2020 by constructing the comprehensive index series of drought disaster and base on the four indicators series such as crop sown,drought affected,and disaster affected areas,and grain loss due to drought and the spatio-temporal distribution characteristics and change trend of drought disasters in China were analyzed.The statistical results show that rates of drought affected area,disaster affected area and grain loss have increased from 1949 to 2000,by 1.72%/10 a,1.26%/10 a and 0.61%/10 a,respectively,but the drought disaster have decreased gradually from 2001 to 2020 on the time scale.In terms of spatial distribution,the agricultural drought disaster is more severe in the Northeast,Northwest and Huang-HuaiHai regions,where the rates of drought affected area and disaster affected area are more than 15%and 10%.While the drought disaster rate is relatively slow in the South China,Southwest and Middle-lower reaches of the Yangtze River regions,where the rates of drought affected area and disaster affected area are lower than 10%and 5%.According to comprehensive drought index,there are 26 years of above severe drought and 13 years of extreme drought from 1949 to2020 in China.There were 10 provinces with above severe drought before 1980,but there were expanded to 16 after 1980,which means that China is a country with frequent drought disasters.This study also concluded that climate warming and human activities are the main drivers of the aggravation of drought disasters in China.The annual precipitation in the HuangHuai-Hai,southwest and other regions showed a decreasing trend from 1961-2020,average annual surface temperature showed a significant increasing trend from 1951-2020 in China,with temperature increasing at 0.26℃/10 a.Unsustainable human activities were found to contribute to agricultural drought disasters by disrupting crop water income and expenditure,the drought disaster were more severe,to a certain extent.