OMI Trace Gas Products

OClO for 8 August 2005, fitted slant columns from the 15 orbits

The image above shows monthly average HCHO for September 2006, including only pixels with cloud fraction up to 20%

Total column and slant column values of trace gases, BrO, HCHO, and OClO will be produced using DOAS-type of techniques, which fit a differential absorption spectrum. The OMI algorithm will detect volcanic ash and sulfur dioxide produced in volcanic eruptions with up to 40 times more sensitivity than TOMS and GOME.
Ahmad, et al., Proc. SPIE Int. Soc. Opt. Eng. 5151, 619 (2003)

The atmospheric trace gases BrO, HCHO, and OClO also have absorption features that fall in the OMI wavelength range. Because of OMI's hyperspectral capability these gases can be retrieved using DOAS or similar algorithms. DOAS algorithms have been successfully employed for GOME and SCIAMACHY and have been also applied to ground-based measurements. The method involves fitting the spectroscopic features in the measured Earth albedo and accounting for Fraunhofer structures due to rotational Raman scattering (the Ring effect). From the fit, slant columns are derived that are converted to vertical columns using radiative transfer models and a general assumption for the measured constituent.s vertical profile. This method is applied to BrO and HCHO. For OClO, only slant columns are possible because its profile is poorly known. Formaldehyde (HCHO) biomass burning events above South America, South Africa, and Indonesia, as well as BrO above ice fields at the South Pole, have been detected by OMI.
Levelt, et al. Geoscience and Remote Sensing, IEEE Transactions on, Vol.44, Iss.5, May 2006 Pages: 1199-1208

WE ARE REPROCESSING OMI DATA WITH THE LATEST CALIBRATION.
PLEASE READ THE 'NOTE' ON THE MEASUREMENTS PAGE OF THIS SITE.

COLLECTION 3 VERSIONS OF ALL PGEs ARE EXPECTED TO BE DELIVERED
SOON.