Mineral content analysis of atmospheric dust using hyperspectral information from space

Abstract

The Bodélé depression of northern Chad is considered one of the world's largest sources of atmospheric mineral dust. Mineral composition of such transported dust is essential to our understanding of climate forcing, mineralogy of dust sources, aerosol optical properties, and mineral deposition to Amazon forests. In this study we examine hyperspectral information acquired over the Bodélé by EO-1 Hyperion satellite during a dust storm event and during a calm clean day. We show that, for the suspended dust, the absorption signature can be decoupled from scattering, allowing detection of key minerals. Our results, based on the visible and shortwave infrared hyperspectral data, demonstrate that the Bodélé surface area is composed of iron-oxides, clays (kaosmectite) and sulfate groups (gypsum). Atmospheric dust spectra downwind of Bodélé reveal striking differences in absorption signatures across shortwave infrared from those of the underlying surface. Copyright 2009 by the American Geophysical Union.