Remote sensing methods as a base for landform and soil maps of the Iranian loess plateau

所谓的伊朗黄土高原，位于伊朗北部的土库曼草原上，是一个独特的景观，被黄土覆盖，厚度至少达70米。近年来的沉积学和年代学研究表明，这些黄土沉积作为第四纪景观演化和气候变化的记录具有很高的价值。此外，这些沉积为东南欧和中亚的黄土沉积提供了联系，因此对地层对比具有重要意义。黄土高原面积约2250平方公里，位于戈尔干河和阿特雷克河的交汇处，这两条河流经北部的阿尔博尔斯山脉和东部的科佩达格山脊。黄土及其下伏地层的构造隆升、深蚀和河谷切割造成了黄土高原的明显起伏。这些山脊高出谷底约80米，主要由黄土组成。频繁的黄土井、沉坑、管道和沟渠反映了地表和地下强烈的侵蚀过程。土壤发育与坡向密切相关，因为北坡植被保护土壤表面免受侵蚀，有利于Cambisol的形成和保存，而南坡土壤可能受到侵蚀，形成发育较弱的entisol。关于土壤和植物覆盖、高原地形特征以及土地利用的潜力和问题的空间资料非常有限。为了全面记录、分析和解释黄土高原的地貌、土地利用和土壤分布，遥感可以提供重要的数据和工具。必须考虑到遥感数据的不同来源。在这里，高分辨率立体卫星图像将用于导出两个试验区异质景观的详细数字高程模型（1米）。此外，还将利用其他可用的多光谱和高光谱卫星图像来获取整个黄土高原的信息。这些数据将使人们能够绘制某一地区的地图，其中包含有关地形特征、岩性和土地利用的资料。导出的参数可以进一步用于导出建议区域的数字土壤图。特别是，高分辨率遥感数据（1米）对这一特定地形的适用性和准确性将通过与涉及地面激光扫描、DGPS挖沟和地面真值测绘的实地行动数据进行比较来评估。不同数据来源的汇编将增加我们对黄土高原地形特征、岩性单元、土壤和植被的空间分布以及这一偏远地区地貌演变的认识。

The so called Iranian loess plateau, located in the Turkmen steppe of Northern Iran, is a unique landscape covered by loess, up to at least 70 m thick. Recent sedimentological and geochronologcial investigations show that these loess deposits have high value as records of Quaternary landscape evolution and climate change. In addition, these deposits provide a link between loess deposits in Southeastern Europe and Central Asia and are thus of large importance for stratigraphic correlation. The loess plateau covers an area of about 2250 km2 and is located in the interfluve of the rivers Gorgan and Atrek, which drain the Northern Alborz Mountains and the eastern part of the Kopeh Dagh ridges. Tectonic uplift, deep erosion and valley incision into the loess and underlying strata caused the pronounced relief of the loess plateau. The ridges rise to about 80 m above the valley floors and mostly consist of loess. Frequent loess wells, sink holes, pipes and gullies reflect intense erosion processes at the land surface and below. Soil development strongly relates to slope aspect, because on northern slopes vegetation protects the soil surface against erosion and facilitates formation and preservation of a Cambisol, whereas on south-facing slopes soils were probably eroded and weakly developed Entisols formed. Very limited spatial information is available on the soil and plant cover and the relief features of the plateau, as well as on potentials and problems in land use. For the comprehensive documentation, analysis and interpretation of the landform, land use and soil distribution within the loess plateau, remote sensing may provide crucial data and tools. Different sources of remote sensing data must be regarded. Here, high-resolution stereo satellite imagery will be used to derive detailed digital elevation models (1 m) for the heterogeneous landscape in two test areas. Furthermore, other available multi- and hyperspectral satellite imagery will be used to derive information for the entire loess plateau. The data will enable to establish maps of a certain area containing information on landform features, lithology and land use. The derived parameters can be further used for the derivation of digital soil maps of the proposed area. In particular, the applicability and accuracy of high-resolution remote sensing data (1 m) for this specific relief will be evaluated by a comparison to data of a field campaign that involves terrestrial laser scanning, DGPS trenching and ground truth mapping. The compilation of different data sources will enhance our knowledge on the spatial distribution of relief features, lithological units, soils and vegetation in the loess plateau as well as on the geomorphological evolution of this remote region.