Atmospheric Pollutants Dust and Haze

Dust is characterized by a dull, hazy and filmy appearance similar to thin cirrostratus. Dust can extend to adjacent water bodies and sometimes obscure the coastline. The edges of dust areas are ill defined.

Blowing dust and sand can be observed in satellite imageries when the reflectivity of the suspended particles differs greatly from the reflectivity of the underlying surface.

Haze particles scatter quite effectively at the blue end of the visible wavelength (channel 1) and hence areas of haze show up better in images of this channel.

Particles of dust or sand carried by the wind form a cloud that causes land marks to appear blurred or to disappear in VIS images. To be detected in IR imagery a dust cloud must be very deep. There are two reasons for the same. Firstly the dust must be composed of large enough particles (over 15 m) to obscure radiation emitted from the ground at least partially. Secondly it must be deep enough to have low temperature otherwise it will not be able to distinguish it from the surface.

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