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Spectral characterization of desert surfaces in Kuwait by satellite dataAl-Doasari, Ahmad January 1994 (has links)
Thesis (M.A.)--Boston University / This study is a part of an environmental impact assessment of
the Gulf War on the desert and the coastal zones of Kuwait. Due to
the appearance of many new surface features, a study was necessary
to characterize their spectral signatures as detected by Landsat
Thematic Mapper (TM) data. A sophisticated image analysis was
applied to the Landsat TM scene. An unsupervised classification
technique produced a thematic map of the area.
Data was collected on the ground at eighty sites in southeastern
Kuwait. A radiometer (SE-590) was used to identify the spectral
reflectance of desert surface features. A Global Positioning System
(GPS) reading on each site was also recorded to register accurately
the field observations on a specific pixel from over 72 million pixels
in the lower right scene of Kuwait.
Field data were collected on surface feature color, soil grain
stze, vegetation types and density, and the amount of oil or soot
contamination. Statistical correlation's and companson of Landsat
and the SE-590 measurements in the visible and near-infrared bands
describe the interaction between radiation and different desert
surfaces. The oil lakes class was identified to have the lowest
reflectance of all the classes. Brightness values gradually increase as
less oil, soot or desert vegetation is found. The highest brightness
value belongs to the class which represents active sand.
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Analysis of the changes in the tarcrete layer on the desert surface of Kuwait using satellite imagery and cell-based modelingAl-Doasari, Ahmad E. January 2001 (has links)
Thesis (Ph.D.)--Boston University / The 1991 Gulf War caused massive environmental damage in Kuwait.
Deposition of oil and soot droplets from hundreds of burning oil-wells created a layer of
tarcrete on the desert surface covering over 900 km'. This research investigates the
spatial change in the tarcrete extent from 1991 to 1998 using Landsat Thematic Mapper
(TM) imagery and statistical modeling techniques. The pixel structure ofTM data allows
the spatial analysis of the change in tarcrete extent to be conducted at the pixel (cell)
level within a geographical information system (GIS).
There are two components to this research. The first is a comparison of three
remote sensing classification techniques used to map the tarcrete layer. The second is a
spatial-temporal analysis and simulation of tarcrete changes through time. The analysis
focuses on an area of 389 km' located south of the Al-Burgan oil field.
Five TM images acquired in 1991, 1993, 1994, 1995, and 1998 were
geometrically and atmospherically corrected. These images were classified into six
classes: oil lakes; heavy, intermediate, light, and traces of tarcrete; and sand. The
classification methods tested were unsupervised, supervised, and neural network
supervised (fuzzy ARTMAP). Field data of tarcrete characteristics were collected to
support the classification process and to evaluate the classification accuracies. Overall,
the neural network method is more accurate (60 percent) than the other two methods;
both the unsupervised and the supervised classification accuracy assessments resulted in
46 percent accuracy.
The five classifications were used in a lagged autologistic model to analyze the
spatial changes of the tarcrete through time. The autologistic model correctly identified
overall tarcrete contraction between 1991-1993 and 1995-1998. However, tarcrete
contraction between 1993-1994 and 1994-1995 was less well marked, in part because of
classification errors in the maps from these time periods. Initial simulations of tarcrete
contraction with a cellular automaton model were not very successful. However, more
accurate classifications could improve the simulations.
This study illustrates how an empirical investigation using satellite images, field
data, GIS, and spatial statistics can simulate dynamic land-cover change through the use
of a discrete statistical and cellular automaton model.
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