基于多源数据的干旱区盐渍地信息提取

土壤盐渍化严重威胁着干旱区绿洲的稳定与可持续发展，因此借助遥感手段快速提取盐渍地信息并及时掌握其空间分布有着重要的现实意义。以塔里木盆地北缘盐渍地普遍发育区域库车绿洲为例，探讨了干旱区以盐生植被红柳为主要覆盖的盐渍地信息的提取方法。综合利用TM卫星图像数据以及Radarsat雷达数据，分析了研究区主要地物的光谱特征及其波段间的相互运算，从而分析盐渍地与其它地物之间的可分性。着重分析了雷达波段作为一个波段加入ETM的6波段中一起参与主成分变换后对盐渍地信息的提取。研究表明：K-L-5（第五主成分）是提取重度盐渍地信息的最佳波段，TM1是区分红柳覆盖区（轻、中度）盐渍地信息的最佳波段，提取盐渍地信息时混分的水体信息可以通过MNDWI（改进归一化差异水体指数）设定一定的阈值予以剔除，混分的植被信息可以通过NDVI设定一定的阈值予以剔除。根据以上分析，建立决策树模型进行盐渍地信息的提取。结果表明，该方法的总体提取效果较好，是干旱区监测盐渍地变化的有效手段。同时也说明由于雷达波段的参与增加了盐渍地与其它地物之间的可分性，为雷达影像在提取盐渍地信息方面提供了一条有效途径。

Study on the Extraction of Saline Soil Information in Arid Area Based on Multiple Source Data

Soil salinization has severely threatened the inner stability and the sustainable development of oasis in arid areas,so extracting the saline soil information rapidly based on remote sensing and mastering its spatial distribution are of important practical significance.In this article,taking the Kuqa oasis as the example,TM image collected on August 2001 and Radarsat image collected on Mar 2001 were used.The approach of effective remote-sensing information extraction for saline soil was discussed.The mechanism and characteristics of saline soil and other objects was analyzed to find the possibility of extracting saline soil from the background.The analysis was focused that the radar-band as a band to join the six bands of ETM together was taken to perform the principal component transformation to extract the saline soil information.The research shows that K-L-5 is the best band to extract severe saline soil information,TM1 is the best band to differentiate saline soil information with the salt-tolerant vegetation of Hongliu and the mixed water body and vegetation information can be separated by the index of MNDWI and NDVI.Then,based on the analysis,a simple model of decision tree was applied to extracting saline soil information.Finally,the results were checked by statistical accuracy assessment.The results suggest that the model of decision tree was simple and effective and the precision of this approach was very high,so it was an effective method for monitoring saline soil changes in arid area.It also showed that the separability between the saline soils and other classes was increased due to the participation of radar band,and an effective way was provided to extract saline soils information using radar images.