To map the surface of the dunes and the desert floor beneath the dunes, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) GDEM v2 was chosen as the primary elevation source. To reconstruct the regional paleo drainage system, the ETOPO1 Global Relief Model was downloaded from the NOAA, National Centers for Environmental Information using the grid-registered version of the dataset. With a spatial resolution of 1.8 km 1 arc minute, ETOPO1 is also well-suited for this type of regional-scale analysis that covers the entire Arabian Peninsula. While any DEM can be used to generate an artificial network of streams, ETOPO1 is the only global DEM that provides elevation data for both the land surface and the ocean floor. For the true color band combination, MODIS imagery has a spatial resolution of 500 m, the purpose of the analysis is to classify and map the major color difference in the sand surface across the entire dune field. These four scenes were then mosaicked and clipped to the study area using the boundary defined by the Saudi Geological Survey (2011). Comparing these sources, the Landsat Four MODIS data scenes were downloaded from the USGS GloVis (Global Visualization Viewer). Today there are many satellite platforms and sensors that provide images of the Earth’s surface. To investigate the potential sources of sand and estimate the total sand volume in the Rub’ al Khali based on sand dune color, field investigation, laboratory analysis of sediments, and visual interpretation of satellite data are required to be considered. With the dry Arabian Gulf exposed as a source, winds from the northwest could transport an enormous volume of sand over a period of thousands of years. More importantly, recognized that the Arabian Gulf was dry during the last glacial maximum (17,000–25,000 BP) when sea level was about 120 m lower than today. In this regard, was the first to suggest that wadis flowing eastward from the Arabian Shield mountains contribute local sand to the western part of the dune field. Given the eastward orientation and slope of the Rub’ al Khali basin and the alignment of dunes with respect to dominant northwest winds, there is a strong consensus that the sand dunes have developed from both local and regional sources. This observation raises interesting questions with regard to the origin and age of the dunes. This suggests that the yellow sand might be derived from both local and regional sources, or it might be less oxidized, reworked, or have a different composition that represents a combination of red and white sand.Ī question has always existed as to the reason why such a huge amount of quartz sand exists in the Rub’ al Khali, while the surrounding geology consists largely of carbonates.
Yellow sand covers most of the western part of the dunes field and seems to be a transitional color between red and white sand in the eastern part of the dune field. The red sand is quite pronounced, the largest volume of sand (~36%) is associated with the yellow color class. If this is true, a spatial variability map of the mineral composition of the sand could be very revealing. The analysis of dune color strongly suggests that the sand is not completely reworked and intermixed. The main objective here is to identify and map different dune forms within the sand sea, estimate the volume of sand and explore probable sources of sand. This study takes advantage of geospatial technology (interpolations, supervised classification, minimum focal statistic) to extract information from the data contained in global Digital Elevation Model (DEM)s, satellite imagery. Located on the southern Arabian Peninsula, the dune field has remained largely unexplored owing to the harsh clime and difficult terrain. The Rub’ al Khali desert (or Empty Quarter) is the largest and perhaps most significant sand sea in the world.
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