陕北北部植被生态环境变化遥感监测及对径流的影响分析

Remote Sensing in Monitoring the Vegetation Variation in the North of Northern Shaanxi as well as its Influence on the Runoff

对陕北北部植被指数增幅进行分析,本文利用1998～2004年NOAA卫星遥感资料,采用归一化植被指数方法,发现陕北植被指数增幅在50%～200%之间,其中吴旗增幅最大。通过对延安北部及榆林市年降水量资料分析,得出植被指数增加不是由于降水变化引起的,是退耕还林草工程已初见成效。对吴旗县降水量和径流量进行时间序列相关分析、典型年对比分析,表明该县植被变化对年径流通量产生了影响,年径流量和泥沙量减小近一半。

By making use of the remote sensing information between 1998 and 2004, the method of Normalized Difference Vegetation Index （NDVI） was applied to analyze the vegetation index increment for the north part of Northern Shaanxi. it was found that the vegetation increment was in the range of 50% to 20% ,with the highest increment with Wuqi county. The analysis of the runfall in the north of Yan＇an as well as in Yulin prefecture showed that increment of vegetation index was attributed to the effect brought by the land conversion program instead of the rainfall variation. Rainfall as well as the runoff analysis showed that vegetation variation influences the runoff, reducing the annual runoff and sediments by half actually.