高时间分辨率遥感在土壤质地空间变化识别中的应用

在土壤信息推测研究中,遥感技术通常被作为辅助手段,用来提供地形和植被数据,并利用它们与土壤之间的关系推导土壤空间信息。然而,在平原等地形平缓的农业区,易于观测的地形和植被等环境因素,通常与土壤的协同程度较低,不能有效用于推测土壤质地等属性的空间变化。对于这类地区,如何寻找新的易于获取的变量,以准确地揭示土壤属性的空间变化,是需要解决的问题。本文提出了利用高时间分辨率遥感捕捉这类地区土壤质地空间变化的方法。采用光谱-时间响应线对多时相的光谱数据进行组织表达,使用光谱信息散度定量刻画不同光谱-时间响应线之间的差异。结果显示,在相同的地形和植被条件下,土壤质地相同的区域,其地表动态反馈模式明显相似;土壤质地不同的区域,其反馈模式也明显不同;土壤质地越相似,反馈模式也呈相似趋势。这表明,高时间分辨率遥感获取的地表动态反馈能够有效地指示土壤质地的空间差异。本文的工作表明了高时间分辨率遥感在土壤空间变化识别方面的应用潜力。

Application of High Temporal Resolution Satellite Remote Sensing in Identifying Soil Texture Patterns

Soil is the most basic and most important resource for the living and development of human beings.At present,there is an urgent need to obtain accurate soil spatial information for environmental modeling and agricultural applications.The theory of soil-landscape relationships relates difficult-to-measure soil information,which includes soil type and properties,with some easy-to-obtain soil-forming environmental factors.This makes it possible to infer soil spatial variations from the easy-to-obtain environmental factors.Satellite remote sensing techniques generally serve as auxiliary tools for researches on soil spatial information extraction.The techniques can be used to acquire landform and vegetation data.Then,based on their relationships with soil conditions,soil spatial variation can be derived.In areas with median to strong landform gradient,easy-to-measure landform and vegetation factors have played an important role in soil mapping.However,for the plains and topographically gently undulating areas,where spatial variation of soil properties such as soil texture usually cannot be effectively indicated by the landform and vegetation,a scientific problem is how to reveal spatial variation of soil properties.This paper presents an approach to using land surface dynamic feedback captured by high temporal resolution remote sensing over a short period immediately after a major rain to distinguish soil texture over such areas.The results of this study showed that land surface dynamic feedbacks captured by high temporal resolution remote sensing can be used to identify spatial variation of soil texture.Locations experiencing different soil texture have obviously different dynamic feedbacks,and the more similar the soil texture between locations the more similar their dynamic feedbacks.The findings are very encouraging.The work reported in this paper provides an effective solution to the difficulty of identifying soil spatial variation over low relief areas.It exhibits the potential of high temporal remote sensing on the exaction of soil information.