西南地区农业旱情的气象干旱指数适应性研究

Research on the adaptability of meteorological arid index of agricultural drought in Southwest China

利用西南地区60站1961—2011年的日平均气温、降水量资料求得半年尺度的气象干旱指数值,包括帕尔默干旱指数、标准化降水干旱指数、Z指数、降水距平百分率指数。采用超前相关、相似和技巧评分两种计算方法检测与西南地区农业灾情最适宜的气象干旱指数。基于最适宜的干旱指数,给出西南地区农业干旱灾害可能发生的风险分布。结果表明:Z指数定义的冬半年气象干旱对西南地区农业旱情的指示性较其他3种气象干旱指标更优。冬半年Z指数小于等于-0.84时引发的西南地区农业干旱灾害成灾率大于8%的风险平均达0.53,农业干旱绝收率大于5%的风险平均达0.37,风险最大地区位于贵州西北部。结论有助于深入认识气象干旱指数与农业干旱灾情的联系,对于西南地区农业干旱的检测预测有一定的应用价值。

By using the daily mean temperature and precipitation data from 60 observation stations in Southwest China from 1961 to 2011, the half-year scale meteorological drought index values, including Palmer drought index, standardized rainfall drought index, Z index and precipitation anomalies percentage, are collected. Methods of lead correlation, similarity and skill score are adopted to detect the most suitable meteorological drought index related to the agricultural disasters in Southwest China, based on which, the possible risk distribution of agricultural drought disasters in Southwest China is obtained. The results show that the meteorological drought in winter half-year defined by Z index is much more indicative on the agricultural drought in Southwest China than the other three kinds of meteorological drought indexes ; when Z index in winter half year is ≤ -0. 84, its raising risks of the 〉8% agricultural drought disaster rate and the 〉5% agricultural drought crop failure rate amount to 0. 53 and 0. 37, respectively, and the highest risk area is in the Northwest Guizhou. The conclusion not only help to know the connection between the meteorological drought index and agricultural drought disaster thoroughly, but has certain application value in the detection and prediction of agricultural drought in Southwest China.