OMI Ozone measurements: OMDOAO3 (DOAS Total Ozone column)
- Total ozone columns from OMI measurements derived via the DOAS method are publicly available within 48 hours after observation at the GES-DISC.
- Images of OMI total ozone columns derived via the DOAS method are publicly available shortly after observation at FMI's VFD site (within 30 minutes, Europe only) and at the TEMIS NRT sites (within 3 hours, global).
The KNMI total ozone algorithm is based on the DOAS technique that has been widely used to measure trace gases from ground. It has been applied successfully to process data from the GOME and SCIAMACHY instrument that are currently flying on the ERS-2 and ENVISAT satellites. This ozone column is estimated from longer wavelengths than those used in the TOMS algorithm. In principle, DOAS is less sensitive to disturbing effects by absorbing aerosols, SO2, and calibration errors than the TOMS algorithm. The OMI DOAS algorithm uses a different spectral window (331.6 - 336.6 nm) to GOME and SCIAMACHY, chosen such that the retrieval does not depend on external information of atmospheric temperatures.