气候变化对中国农业旱灾损失率的影响及其南北区域差异性

摘要

The impact of drought on agricultural production is getting worse and worse in China under the climate change,but due to the complexity and its significant regional differences of disaster loss caused by drought,the understanding of the law and the mechanism for the agricultural loss caused by drought are very limited.In this paper,using the data of Chinese agricul-tural drought disaster and the conventional meteorological data since 1961,a more systematic analysis of the disaster loss index trends is made,such as the different intensity disaster ratios and the comprehensive agricultural loss rate caused by the agricul-tural drought,and the regional differences in the North and the South of the past 50 years.We researched the characteristics that the temperature mutation have the effects on the agricultural loss caused by drought since 1990s,we discussed also the de-pendence between the comprehensive agricultural loss rate and the climatic factors of temperature and precipitation,as well as the distribution characteristic of the agricultural loss rate in the climatic space.The results showed that the comprehensive agri-cultural loss rate increased by an average of 0.5% per decade in the past 50 years,and the risk increased significantly under the climate change.Moreover,the comprehensive loss rate is increased by about 0.6% per decade in the North,higher one time than the South,with the increasing of risk faster significantly than the South.The North agricultural drought disaster can oc-cur in a loose temperatures condition,and it occurred in the years with the higher temperatures in the South.And,the war-ming trend is increasing clearly after the temperature mutation,with the national comprehensive loss rate is increased by about 0.9%,and higher significantly risk;and the increment is 1.8% in the North,about four times higher than the South,sugges-ting that the North climatic mutation has more prominent impact on the agricultural drought disaster risk than the South.The response of the North comprehensive loss rate to precipitation is more sensitive than the South,but the South is more sensitive in terms of temperature.Meanwhile,the impact of the key periods temperature and precipitation for the comprehensive loss rate is more significant than the annual;in the key periods the North is more prominent in terms of precipitation than the South.These new scientific understanding has important implications for agricultural drought disaster prevention in China.%在全球变暖背景下，干旱灾害对中国农业生产的影响日益严重，然而由于旱灾损失的复杂性及其显著的区域差异，至今对中国农业旱灾损失规律及其影响机制的认识十分有限。文中利用1961年以来中国农业干旱灾害的灾情资料和常规气象资料，系统分析了近50年来中国农业干旱灾害不同受灾强度分布比率和综合损失率等指标的变化趋势及其在北方和南方的区域差异，研究了20世纪90年代的气温突变对农业旱灾损失率的影响特征，探讨了农业旱灾综合损失率对气温和降水等气候要素变化的依赖关系及其在气候空间的分布特征。结果发现，在气候变化背景下，近50年来中国农业旱灾综合损失率平均每10 a 约增加0．5％，风险明显增大。而且，北方综合损失率每10 a 约增加0．6％，高出南方1倍，风险增大的速度明显比南方快；北方农业旱灾几乎在很宽松的气温条件下就可以发生，而南方更多发生在气温较高的年份。并且，在气温突变后，变化趋势明显加剧，全中国综合损失率约增加了0．9％，风险明显增高；而且北方综合损失率的增值高达1．8％，是南方的4倍还多，气候突变对北方农业旱灾风险的影响明显比南方更凸出。综合损失率在北方对降水变化的响应要更敏感，而在南方对气温变化的响应更敏感。同时，关键影响期降水对综合损失率的影响比全年降水影响更显著；北方的关键影响期作用比南方更凸出。这些新的科学认识对中国农业旱灾防御具有重要意义。