大同市干旱成因特征分析及其对农业生产的影响

The Analysis on Drought’s Formation Characteristics in Datong and Its Influence on Agricultural Production

摘要: 为分析大同市干旱发生的成因及其气候特征，用大同市1970~2012年的降水资料，采用降水量距平百分率指数，划分干旱等级，对干旱发生的频率及时间序列变化等进行分析研究，结果是：受特殊地形和天气系统的影响，给我市农业生产造成不利后果的主要是春旱和秋旱，夏旱次之，严重干旱最长周期具有9年的变化特征。

Abstract: To study the cause of drought and its climate characteristics in Datong city, the precipitation data of Datong from 1970 to 2012 is used. By using the precipitation anomaly percentage index, the drought level is divided and the frequency of drought occurrence and the change of time series are analyzed. The result showed that the spring and au-tumn droughts are the main factors caused adverse effect to agriculture of Datong affected by the special terrain and weather system, the summer drought is the second, and the longest period of severe drought has 9 years’ changing characteristics.