环青海湖天然草地干旱指标筛选及干旱等级划分

THE SELECTION OF DROUGHT INDEX AND LEVELING ITS DIVISION OF NATURAL GRASSLAND AROUND QINGHAI LAKE

本文采用气象干旱指标法和农业干旱指标法分析环湖地区天然草地干旱指标等级。结果表明:青海环湖地区天然草地干旱的降水量月尺度距平百分率(Pa)干旱等级划分指标是-65<Pa<-50时轻旱;Pa<-95时特旱;土壤水分(重量含水率W)干旱等级划分指标是10<W<15时轻旱;W<3时特旱。以上指标在理论上是一致,对环湖地区的预报准确率比较高。

This paper uses the meteorological drought index method and agricultural drought index method to analyze the drought index level of natural grassland around the Qinghai Lake.The result shows that the monthly scale anomaly percentage(PA)of precipitation of natural grassland drought around the Qinghai Lake is-65<PA<-50 of light dry;and PA<-95 of extreme dry.The drought level index of soil moisture(weight moisture content w)is light dry when it is 10<w<15;and it is an extreme dry when it is w<3.The above two indexes are consistent in theory,and therefore they have certain operational application values in the drought prediction of natural grassland around the Qinghai Lake.