Detection of desert dust aerosol using S5P DOAS observations.

In many arid parts of the world, dust from deserts and other dry surfaces can be upliftedinto the air and become the largest fraction of atmospheric aerosols. Dust aerosoloutbreaks can affect large areas, and have important effects on air quality, visibility,human health, and also on the transport of trace elements towards remote oceanregions. Desert dust outbreaks can be observed from space in visible satellite imagesand quantified by aerosol retrieval methods which separate the contributions fromsurface reflection, scattering on air molecules and scattering by particles on theobserved top of atmosphere reflectance based on the analysis of discrete wavelengthbands. A few years ago, a spectral interference of the surface spectral reflectance of deserts wasfound in GOME-2 satellite retrievals of atmospheric nitrogen dioxide (NO2) from spaceborne observations in the wavelength region 450 - 497 nm. This spectral signature whichappears to be unique to certain desert soils was subsequently also identified in measurementsof other satellites and in airborne data. Here, we use measurements of the TROPOMI instrument on the recently launched S5Psatellite to investigate the global distribution of the spectral sand signal and show that it is notonly found over deserts, but can also be used to detect large desert dust aerosol events, mainlyover the ocean but also over land. [ABSTRACT FROM AUTHOR]