notifiable percentage level

The paper Based on the 1959 to 2008 data of precipitation in Huhhot,used Precipitation anomaly percentage and linear analysis methods to analyze trends in drought Hohhot,found that the following characteristics:(1) precipitation variability rate is high,drought frequency as high as 44.

以内蒙古呼和浩特市50年(1959-2008年)降水资料为基础,以降水量距平百分率气象干旱标准为依据,运用线性分析法,研究呼和浩特市干旱的变化趋势,发现呼和浩特市干旱存在以下特征:(1)呼和浩特市降水变率大,干旱发生频率高达44。