基于多时相遥感反射光谱特征的土壤盐碱化动态变化监测研究

Research on Monitoring the Dynamic of Salt-affected Soil Using Spectral Feature of Temporal Remote Sensing Imagery

利用遥感技术动态监测土地利用和土地覆盖状况具有快速、准确、及时的特点。土壤反射光谱在近红外和红色波段具有很好的相关性,在遥感影像上形成了土壤特有光谱特征,即土壤线。土壤线特征为在遥感影像上快速准确地选择分类样本训练区提供了一个有效途径。基于多时相的TM和IRS影像,通过遥感影像上的土壤线特征选择训练样本,利用最大似然法,对内蒙古河套灌区1988、1996、2001和2006年的遥感影像进行分类,形成了该地区多年土壤动态变化专题图,基于野外土壤调查数据对分类结果进行验证。研究结果表明,河套灌区的盐碱地和沙丘地所占比例在呈下降趋势,非盐碱地呈上升趋势,基本上反映了河套灌区多年来土壤类型动态变化状况与治理土壤盐碱化的初步成果。

Remote sensing is an effective way to monitor the change of land cover and land use. Soil line, the response of high correlation between red and near-infrared band of soil spectral, can be taken as one of the tools helping to collect training samples in the process of classification. The principle of soil line based on sample collecting is that pixle position plotted on the soil line have distin-guished salt=affected features. Basing multi-temperal LandSat TM and JRS imagers and selecting training samples aided by the soil line, the maximum likelihood classification method is employed to identify the area of salt-affected land surface in the year of 1988, 1996,2001 and 2006. The classification results are validated using the field experiment dataset and the theme map is produced for the 4 years. The research results reveal that there is a decline trend for the proportion of both salt-affected and sandbank area to the full land area in Hetao Irrigation Disctrict, which can be explained by many years＇ efforts to improve the quality of soil By rationalizing the irrigation and drainage in this region.