A Collaborative Research on Combating Desertification in Naiman,Inner Mongolia,China with Institute of Desert Research,CAS——Results of Desertification Monitoring Using RS and GIS

奈曼地区的沙漠化以固定沙丘的活化为特征。研究利用陆地卫星资料监测地被物和土地利用变化的方法以分析沙漠化的进展。天然植被、结构和土壤红度指数对分析沙漠化现状及发展趋势很有效。研究证实 ,典型区的沙漠化程度有明显变化 ;对居民区 ,公路及铁路沿线附近地区的土地管理比较重视 ,正在对沙漠化土地进行改良。应用上述方法可以分析沙漠化现状及发展趋势但不能确定其面积的变化。其次根据调查分类提出了地被物和土地利用变化的监测法。此法要求提供一年中两次不同时间的数据。文中还分析使用此法的可能性。最后 ,根据陆地卫星红色谱带反射率与实测生物之间的高度相关性可估算草地的生物量并得出结论 ,从奈曼北部到中部的大部分地区都处于过度放牧状态。     

Statistical analyses and modeling approaches to hydrodynamic characteristics in alluvial aquifer

This study is aimed at quantifying the difference in aquifer's response to recharge between some different locations in a fan aquifer and a delta aquifer for a preliminary study of revealing mechanisms of water transport in alluvial aquifer. The aquifer's response to recharge is statistically quantified with the two viewpoints: (1) timing and volume of recharge and (2) time length of aquifer's holding water. For the first point, a statistical model that links precipitation and groundwater level is introduced, and its parameters are identified using correlation analysis. Our results show that the recharge rate at the toe is higher than that at the apex and at the delta. For the second point, the concept of ‘memory effect’ of aquifer is adopted and quantified using the autocorrelation and spectral analyses. Our results show that the memory effect is longer at the toe of fan than at the apex, and thus, a temporary increase of water level has about five times as long‐term influence on subsequent water levels at the toe of the fan as at the apex. This study demonstrates that the statistical analyses and modeling of hydrological data are useful for characterizing aquifer's hydrodynamics. Copyright © 2012 John Wiley & Sons, Ltd.