Comparative Study of Atmospheric Correction Methods of ASTER Data to Enhance the Delineation of Uranium Mineralized Zones

Author(s):  
Mahinaz Shawkya
2010 ◽  
Vol 27 (10) ◽  
pp. 1677-1688 ◽  
Author(s):  
África Barreto ◽  
Manuel Arbelo ◽  
Pedro A. Hernández-Leal ◽  
Laia Núñez-Casillas ◽  
María Mira ◽  
...  

Abstract The land surface temperature (LST) and emissivity (LSE) derived from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data were evaluated in a low spectral contrast volcanic site at an altitude of 2000 m on the island of Tenerife, Spain. The test site is almost flat, thermally homogeneous, and without vegetation cover or variation in its surface composition. ASTER data correspond to six scenes, under both day- and nighttime conditions during 2008. This case study analyzes the impacts of the sources of inaccuracies using the temperature–emissivity separation (TES) algorithm. Uncertainties associated with inaccurate atmospheric correction were minimized by means of local soundings and the climate advantages of the area. Concurrent ground-based radiometric measurements were performed for LST, and laboratory and field measurements for LSE, to obtain reference values. The TES evaluation showed a good level of agreement in the emissivity derived for ASTER bands 13 and 14 [root-mean-square difference (RMSD) lower than 0.002] and discrepancies in ASTER bands 10 and 11 that were within the expected performance of the algorithm (±0.015). However, out-of-threshold errors were retrieved in band 12, producing an artificial increase in spectral contrast. The underestimated TES LSE spectra point to the presence of a roughness effect at measurement scales that may increase the laboratory band emissivity values. TES LST comparison with ground data showed an RMSD value of 0.5 K. ASTER standard products AST08 (LST) and AST05 (LSE) atmospherically corrected by means of Naval Research Laboratory (NRL) data were also tested, showing a similar level of performance for the TES implemented with local soundings, but failed in high-humidity atmospheric conditions.


2015 ◽  
Vol 1 (2) ◽  
pp. 21-25 ◽  
Author(s):  
Sujit Kumar ◽  
Tapasi Bhandary

In this paper, a case-study is presented to differentiate between Landsat and Aster data by morphometric analysis. For this the Aster and Landsat digital elevation model (DEM) data of the same study area was taken and then both the data was delineated for the same (common) outlet. The major differences found in between Landsat and Aster data after delineation are in the number of first order stream, axial length of streams, average width and size of watershed. The case study presented will be useful in demonstrating the fact that Landsat DEM has better accuracy than Aster DEM for land cover areas when the DEM data characteristic are kept similar.


2010 ◽  
Vol 31 (24) ◽  
pp. 6347-6385 ◽  
Author(s):  
Nektarios Chrysoulakis ◽  
Michael Abrams ◽  
Haralambos Feidas ◽  
Korei Arai

Author(s):  
El Zalaky , Abdelmonsif

   The younger granite of El-Erediya pluton represents one of the most important prospect areas in the Egyptian Central Eastern Desert which comprise surface and subsurface U-mineralization confined to the southern part of the pluton. Due to the high uranium airborne anomaly of the northern part than the southern part of the pluton, the granite of northern part need to reevaluate its U-potentiality according to the modern techniques that were developed in the last decade.      The main goal of this paper is to examine the efficiency of the Advanced Space-borne Thermal Emission and Reflectance Radiometer (ASTER) data in mapping the alteration zones that could be host uranium mineralization within the younger granite of El-Erediya pluton using spectral analysis techniques.      ASTER data are especially attractive to many geological researchers in Africa, due to their open availability and associated minimal costs for academic use. The three visible and six near-infrared bands, which have 15-m and 30-m resolution, respectively, were calibrated by using atmospheric correction.      Target detection using spectral-matching algorithm was applied to recognize the most predominant alteration components such as hematite, kaolinte, illite and alunite as more or less considered as path finder of uranium mineralization to trace the most promising zones affected by these alteration within the granite of El Erediya pluton.      Three ASTER-derived promising areas have been detected, including the prospect area, using the matched filtering methods with a confidence ranging from 68 to 95%. All of these zones that delineated by target detection technique show good correlation with those on field and on the reference geologic map.      Two of these target zones are proved in the field and founded along the structural features cutting the northern parts of El Erediya pluton that have not been identified before. Mineralogical studies were carried out, using ore and scanning microscope and XRD, for some selective mineralized samples collected form one of these tow target zones. These investigations confirm the presence of uranophane mineral as uranyl silicates in addition to zircon and fluorite. These minerals are found in close association with hematitization, kaolinitization, and illitization alteration.  


2020 ◽  
Author(s):  
Bruno Oliveira Ferreira de Souza ◽  
Éve‐Marie Frigon ◽  
Robert Tremblay‐Laliberté ◽  
Christian Casanova ◽  
Denis Boire

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