Hydromorphological Mapping and Analysis for Characterizing Darfur Paleolake, NW Sudan Using Remote Sensing and GIS

Elmahdy, Samy Ismail

doi:10.4236/ijg.2012.31004

Cited by 14 publications

(6 citation statements)

References 28 publications

(56 reference statements)

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“…Depressions marked by closed contour lines in this analysis suggest the locations of ancient palaeolake shorelines, many of which may not be detected by conventional stratigraphic and mapping methods because of obscured or eroded shorelines. As support for this assumption, there is a strong agreement between the results of the analysis and the currently accepted extents of large palaeolakes identified by other researchers, including Palaeolakes Bonneville in Utah, USA (Figure 3) (Nishizawa et al, 2013), Chad in Africa (Leblanc et al, 2006) and Darfur, in Sudan, Africa (Elmahdy, 2012; Ghoneim and El-Baz, 2007).…”

Section: Resultssupporting

confidence: 86%

Modeling the connections between internally and externally drained basins using GIS, Google Earth©, and remote sensing

Lee

2018

Progress in Physical Geography: Earth and Environment

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The development of internal drainage is intimately tied to the tectonic and climatic history of an area, but research into the exact causes and processes of internal drainage is constrained by the ability to accurately delineate both internally and externally draining watersheds. Until recently, existing global catalogs of internally drained regions were either hand-drawn or based upon digital elevation models whose resolution is much lower than those currently available. Here, the World Wildlife Fund’s HydroBASINS dataset is analyzed in a GIS program to identify points of former connectivity between endorheic and exorheic basins, to identify possible palaeolakes and palaeo-distributary channels, and to quantify on a global basis the extent of area lost to internal drainage for 101 large watersheds. The results have been made available in Google Earth© KMZ files, and a sample workflow is presented which uses the data to approximate the relative importance of tectonic vs climatic factors in initiating endorheism. As an example of how the dataset and workflow can be used, the drainage history is modeled for endorheic watersheds within two very different tectonic regimes, the Afar region of northeastern Africa and the Northern Territory of Australia. The methodology is readily adaptable to other endorheic basins and offers the ability to create drainage history models which can help in research areas such as climate change investigations and groundwater and economic mineral prospecting.

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Section: Resultssupporting

confidence: 86%

Modeling the connections between internally and externally drained basins using GIS, Google Earth©, and remote sensing

Lee

2018

Progress in Physical Geography: Earth and Environment

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“…This data is one of the most widely used elevation product (Luedeling et al, 2007;Elmahdy, 2011). However flat regions present gaps in areas of low radar backscatter (Nikolakopoulos et al, 2006;Hirt et al, 2010).…”

Section: Characteristics Of the Used Datasetmentioning

confidence: 99%

Mapping palaeolakes in the Ténéré Desert of northeastern Niger using space-borne data for groundwater potential

Molina

Gaber

El-Baz

2017

NRIAG Journal of Astronomy and Geophysics

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Groundwater resources in arid lands are crucial for supporting life. Thus, delineation of low land areas, where surface runoff accumulated during pluvial periods assists in groundwater explorations. Therefore, the drainage patterns in northeastern Niger using various sources of DEMs of optical (ASTER) and radar (SRTM) satellite data were extracted. These data reveal three palaeolakes in the Ténéré Desert. In addition, the DEMs together with the optical and radar satellite data were used to define a major watershed measuring 634,000 km 2 . This watershed may have led to the formation of one major palaeolake as an ancestor of the three palaeolakes. The latter extend to 11,514 km 2 , 17,571 km 2 and 18,453 km 2 . The optical and radar satellites images show that the boundaries of these three lakes have been modified by extensive longitudinal and transverse sand dunes of considerable thickness. These dunes accumulated during a much later arid episode in geologic time, probably during the late Quaternary. Prior to that, the former marshlands received water from the Tibesti Mountains of northern Chad, the Ahaggar Plateau of southeastern Algeria and the Air Mountain of northern Niger. The drainage patterns clearly show the pathway of water down to the ground level. The longest drainage line is emanating from the Ahaggar Plateau and extends south west for 837 km. The water overflow of the southernmost lake led to the formation of another distinct drainage line, leading to the southwestern edge of the ancestral Megalake Chad. This drainage line begins in the vicinity of the town of Fachi and extends southward through the town of Dillia as a single tributary, and is here named the Dillia Palaeoriver. These observations, which are based on the study of satellite data require geophysical fieldwork to ascertain the interpretations, and evaluate the potential for groundwater accumulation in the region.

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“…Remote sensing analysis in paleo-landscape research is a widely used and accepted method. The combination of satellite image data with digital elevation models (DEM) was applied to delineate paleolakes and paleolake related features Gaber et al, 2009;Elmahdy, 2012;Bachofer et al, 2014]. SAR data was used for the mapping of geological features and paleo-landscape in different studies [Dabbagh et al, 1997;Schaber et al, 1997;Abdelsalam et al, 2000].…”

Section: Introductionmentioning

confidence: 99%

Comparative analysis of Edge Detection techniques for SAR images

Bachofer

Quénéhervé

Zwiener

et al. 2016

European Journal of Remote Sensing

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Paleo-shorelines and ancient lake terraces east of Lake Manyara in Tanzania were identified from the backscatter intensity of TerraSAR-X StripMap images. Because of their linear alignment, edge detector algorithms were applied to delineate these morphological structures from those Synthetic Aperture Radar scenes. Due to the physical properties of microwave signals, this application has proven to be a challenging task for edge detectors. This study compares the performance of different combinations of speckle reduction techniques and edge operator in detecting linear paleo-shorelines. The Roberts, Sobel, Laplacian of Gaussian and the Canny edge detector algorithms were applied to extract and revise those linear structures. The comparison shows that the Canny edge detector is especially suitable for images with strong speckle noise. Canny achieves relatively high accuracies compared to the other operators. The stronger the filtering and speckle noise reduction, the better the performance of the other edge detection operators, compared to the Canny edge detector. The application of a wavelet transformation reduces the presence of artifacts resulting from speckle noise and emphasizes the detection of the target features.

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Hydromorphological Mapping and Analysis for Characterizing Darfur Paleolake, NW Sudan Using Remote Sensing and GIS

Cited by 14 publications

References 28 publications

Modeling the connections between internally and externally drained basins using GIS, Google Earth©, and remote sensing

Modeling the connections between internally and externally drained basins using GIS, Google Earth©, and remote sensing

Mapping palaeolakes in the Ténéré Desert of northeastern Niger using space-borne data for groundwater potential

Comparative analysis of Edge Detection techniques for SAR images

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