摘要
利用白银市四站 1957～ 1996年春末初夏的降水资料 ,提出了计算干旱指数的经验公式 ,进一步分析了白银市春末初夏干旱的气候特征。表明干旱频率由南至北增加 ,且 90 %的年份降水偏差一致 ,南片的降水稳定性较好 ;全市连续二年的重旱偶有发生 ,但无连续三年以上的重旱出现 ;干旱周期南片有 7年、4年、11年 ,北片有
Based on precipitation data from 1957 to 1996 of late spring and early summer of four stations in Baiyin,an empirical drought index is built,the drought feature of late spring and early summer is studied.The results indicate that drought frequency raise from south to north in Baiyin,the deviation is identical in about 90% years,but the precipitation in south is twice as much than north,the precipitation in stability south is better than in north.The heavy droughts for two years running occur occasionally,the heavy drought for three or more years running don′t happen.There are 7 and 12 years periods in north,7,4,11,and 20years periods in south.
出处
《干旱气象》
1999年第4期20-22,共3页
Journal of Arid Meteorology
关键词
春末初夏
干旱指数
气候特征
Late spring and early summer
Drought index
Climatic feature
