i Detection of Smoke and Dust Aerosols Using Multi-sensor Satellite ...

4.3 Results
Three dust events occurred in different locations are shown in Figs. 4.6, 4.7, and 4.8,
separately. In Fig. 4.6, the dust storm is floated above the Takalimakan Desert, captured
by Terra MODIS on June 25, 2005. The dust storm is blown in a long-narrow shape. The
detected dust marked with black color in Fig. 4.6b has a good agreement with MODIS
true color image (Fig. 4.6a). The dust in Fig. 4.7 is a large dust storm covered most part
of northeastern China, captured by Terra MODIS on April 7, 2001. The dust storm mixed
with cloud. With the NDDI and BTD (12, 11), the dust pixels (Fig. 4.7b) are separated
obviously from cloud by comparing with MODIS true color image (Fig. 4.7a). Only
small part of dust aerosol pixels over ocean (left bottom corner) is missed in that the
algorithm is mainly focused on the land area. The dust storm in Fig. 4.8 spreads cross two
countries, Pakistan and Afghanistan, on August 10, 2008. Two strings of dust plumes in
the middle of image are identified successfully. Another small dust storm in the right
upper corner is also detected.
The MODIS AOD images at the same region are displayed for the comparison,
shown in Figs. 4.6c, 4.7c, and 4.8c. The spatial resolution of AOD product is 10 km. In
the AOD images, the AOD is not accurately retrieved for the areas with heavy dust
loading. Therefore, in this condition, the detecting results of this algorithm can provide
more accurate information about the dust aerosol than the MODIS AOD product.
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