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，是一片独特的景观，被黄土覆盖，厚度至少有70米。最近的沉积学和地质年代学研究表明，这些黄土沉积物具有很高的第四纪地貌演化和气候变化记录价值。此外，这些沉积在东南欧和中亚的黄土沉积之间提供了联系，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，这两条河排干了北阿尔博尔茨山脉和科佩达格山脊的东部。构造抬升、深部侵蚀和对黄土及其下伏地层的山谷切割导致了黄土高原的显著起伏。山脊高出谷底约80m，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表以下强烈的侵蚀过程。土壤发育与坡向密切相关，因为在北坡，植被保护土壤表面不受侵蚀，并促进风化土的形成和保存，而在南坡，土壤可能受到侵蚀，形成发育较弱的土壤层。关于土壤和植物覆盖、高原地貌特征以及土地利用潜力和问题的空间信息非常有限。为了对黄土高原的地貌、土地利用和土壤分布进行全面的记录、分析和解释，遥感可以提供重要的数据和工具。必须重视不同来源的遥感数据。在这里，高分辨率的立体卫星图像将被用来为两个试验区的不同地貌提取详细的数字高程模型(1米)。此外，还将使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建立某个地区的地图，其中包含地貌特征、岩性和土地用途的信息。提取的参数可进一步用于研究区数字土壤图的提取。特别是，高分辨率遥感数据(1米)对这一具体地貌的适用性和准确性将通过与涉及地面激光扫描、DGPS挖沟和地面实况测绘的实地活动的数据进行比较来评估。不同数据源的汇编将加深我们对黄土高原地貌特征、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了解。

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.