The UV spectral region presents unique challenges and advantages for satellite remote sensing of trace gases and aerosols. Strong Rayleigh scattering, if accurately treated with polarized radiative transfer theory, allows accurate inversions of ozone and other trace gases and provides unique information about clouds and aerosol absorption. In my talk I will describe how accurate radiative transfer codes are combined with important approximations enabling unique UV remote sensing applications ranging from ozone and volcano monitoring to surface UV irradiance mapping to absorbing aerosol detection. UV absorbing aerosols are recognized as key to a complete understanding of tropospheric chemistry, for they have large effects on the amount of biologically active UV radiation, actinic flux, and on photolysis rates of key pollutants (ozone and NO2). Our long-term coordinated ground-based measurements of UV aerosol absorption and UV absorbing gases (ozone, SO2, NO2) are providing critical data for quantitative satellite retrievals.
Currently the Ozone Monitoring Instrument (OMI) on the Aura satellite continues our 30+ year climatic records of ozone and volcanic SO2 by its predecessors (Total Ozone mapping Spectrometers; 1978-2005). OMI’s higher SO2 sensitivity and ground resolution allows monitoring of passive volcanic degassing from space as well as tracking of volcanic plumes for longer times. I will show how hyperspectral imager data has expanded our geophysical knowledge of the atmosphere and enabled new applications in air quality monitoring. With Aura/OMI we are currently able to detect specific SO2 absorption from smelters and power plants that is ~1000 times weaker than concurrent stratospheric ozone absorption. Detection of even weaker anthropogenic sources could become possible with repetitive sampling and higher ground resolution from the NRC decadal survey recommended Geo-CAPE mission.