i Detection of Smoke and Dust Aerosols Using Multi-sensor Satellite ...
i Detection of Smoke and Dust Aerosols Using Multi-sensor Satellite ...
i Detection of Smoke and Dust Aerosols Using Multi-sensor Satellite ...
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idges to determine the modulation transfer function for the Hyperion <strong>sensor</strong>.<br />
Nevertheless, these kinds <strong>of</strong> small ground targets are not appropriate for the MODIS<br />
spatial characterization in view <strong>of</strong> its moderate spatial resolution. Consequently, a desert<br />
area with a series <strong>of</strong> regularly arranged dark targets is chosen in this study for the MODIS<br />
on-orbit spatial characterization. Compared to the approach <strong>of</strong> using its on-board<br />
calibrator, this approach can provide more frequent characterization <strong>of</strong> the MODIS BBR<br />
as it requires no light sources. The deficiency is that it cannot provide spatial<br />
characterization for all b<strong>and</strong>s, only for some RSBs (b<strong>and</strong>s 1-11 <strong>and</strong> 17-19) <strong>and</strong> TEBs<br />
(b<strong>and</strong>s 20, 22, 23, 29, 31, <strong>and</strong> 32).<br />
7.1.3.1 Site for Spatial Characterization <strong>Using</strong> Ground Measurements<br />
The ground targets selected for <strong>sensor</strong> spatial characterization must have high<br />
contrast features. Therefore, different types <strong>of</strong> ground targets could be used for measuring<br />
the BBR shift, such as a dark target, water body, coastline, snow coverage, <strong>and</strong> isl<strong>and</strong>.<br />
The site selected for the MODIS on-orbit spatial characterization is located at the Sahara<br />
desert in Libya, Africa. The latitude <strong>of</strong> this site is from 26.5 0 North to 28.0 0 North <strong>and</strong> the<br />
longitude is from 21.5 0 East to 22.5 0 East. Within this area, more than one hundred dark<br />
targets are arranged regularly in several rows. Each dark target has a circular shape with a<br />
diameter <strong>of</strong> approximately 1 km. The RGB image <strong>of</strong> this site from MODIS remote<br />
sensing measurements is shown in Fig. 7.4(a). The other three images, Figs. 7.4(b), (c),<br />
<strong>and</strong> (d), are taken from Google images with different spatial enlargements.<br />
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