基于江淮分水岭地区的Z指数修正

Adjustment of Z-Index Based on Jianghuai Watershed Area

利用安徽江淮分水岭地区的合肥、六安、巢湖3个代表站1957—2008年汛期5—9月降水量资料,计算成相应的Z指数,在用Z指数作为旱涝分级指标过程中,发现Z指数理论界限值并不符合江淮分水岭地区的实际情况,因此必须对此进行修改和订正。以微调和旱涝年份数量大体对等为原则进行修正,修正后的7级和5级Z指数界限值较好地反映出江淮分水岭地区实际旱涝,因此修正后的Z指数可以应用到安徽江淮分水岭地区汛期旱涝等级划分中。

With the flood-season precipitation data at 3 sampling meteorological stations in Jianghuai Watershed area of Anhui Province from 1957 to 2008,the Z-index method was applied to judge the flood/ drought grades in Jianghuai Watershed area,and it is found that the theoretical Z-index is not suited to Jianghuai Watershed area.In this case the theoretical boundary of Z-index should be adjusted,and there are two principles of adjustment;the first is slightly adjustment,and the second is that years of drought and flood are nearly equal.The new boundaries of Z-index for the grades of flood/drought are more suitable for the Jianghuai Watershed area.Therefore the modified Z-index can be well applied to Jianghuai Watershed area.