甘肃省农业干旱灾害损失特征及其对气候变暖的响应

The Characteristics of Agricultural Drought Disaster Loss and Response to Climate Warming in Gansu,China

随着全球气候变暖,干旱频次和强度增大,粮食生产与安全面临严重的挑战。利用1960—2012年甘肃省农业干旱灾情和气象资料,分析不同干旱程度的农业受灾率、成灾率和绝收率变化特征,并构建了农业干旱灾害风险指数(农业干旱综合损失率),揭示了甘肃农业干旱灾害损失特征及其对气候变暖的响应,讨论了关键时段气象条件对灾害损失的影响,阐述干旱灾害损失在气温和降水气候态中的分布特征,模拟出农业干旱受灾程度的气象阈值,并对未来情景下干旱灾害风险进行预测。结果表明:甘肃省近50多年农业干旱灾害范围、程度和频次均呈增加趋势,粮食受干旱灾害减产的风险加大。受灾率、成灾率、绝收率和综合损失率均呈明显上升趋势,尤其是20世纪90年代气温突变以后干旱灾害损失增大的趋势更明显。21世纪00年代干旱增幅最大,干旱受灾率、成灾率、绝收率和综合损失率均高于全国平均水平。多年平均综合损失率为10.8%,约为全国平均值(5.1%)的2倍。气温和降水量是甘肃农业干旱灾害损失的关键致灾因子,并且关键时段降水量和气温对干旱灾害的影响比全年平均值更加明显,年降水量每减少100mm,综合损失率增加5.6%。年平均气温每升高1℃时,综合损失率增加6.3%。年平均气温6.45℃和年降水量460mm是干旱高风险的临界值。未来气候变暖情境下,甘肃综合损失率增幅将可能达到1.85倍,气候变暖导致农业干旱灾害风险加大。

The food production and food security will face the severe challenge under the climate warming,with the characteristics of increased frequency and intensity of drought,climate change result in an increase on agricultural production risk.In this paper,we calculated the drought-induced rate,drought-occurred rate,no harvest rate and comprehensive agricultural loss rate,constructed a comprehensive agriculture drought risk index-agricultural drought comprehensive loss rate based on the drought disaster data from1960 to 2012,analyzed the risk characteristics of the agricultural loss caused by drought.The results showed that the drought scope,extent and frequency have an increasing trend in Gansu Province for nearly 50 years.The drought-induced rate,drought-occurred rate,no harvest rate and comprehensive agricultural loss rate showed a clear upward trend,especially after the 1990 s,the trend of the drought frequency and intensity increased is clear.The drought-induced rate,drought-occurred rate,no harvest rate and comprehensive agricultural loss rate were higher than the national average.The average comprehensive loss rate is two times for the national average（5.1%）.The comprehensive agriculture drought risk increases with decreasing precipitation,but increases with increasing air temperature,and the comprehensive agriculture drought risk are highly relevant with air temperature and precipitation.Air temperature and precipitation is a major factor caused drought disaster reduction,as well as regional water resources,exacerbated by drought losses and risks.About 6.45 ℃ and460 mm are the critical value of the high drought risk.Under future climate change scenarios,comprehensive risk will increase 1.85 times in the end of the century.Climate change will lead to higher drought risk