Description and validation of the OMI very fast delivery products

Abstract

The Dutch‐Finnish Ozone Monitoring Instrument (OMI) is on board the NASA's Earth Observing System (EOS) Aura satellite. The Aura satellite has a so‐called direct broadcast (DB) capability to broadcast the measurements to ground stations at the same time as the measurements are being stored in the spacecraft's memory for later transmission to Earth. The Finnish Meteorological Institute's very fast delivery (VFD) processing system utilizes this direct broadcast to produces maps of total ozone and ultraviolet radiation over Europe within 15 min after the satellite overpass Sodankylä ground station in northern Finland. The VFD products include maps of total ozone, ultraviolet index, and ultraviolet daily dose. The aim of this service is to provide up‐to‐date information on the ozone and ultraviolet situation for the general public and snapshots of the current situation for scientists. The accuracy of the VFD products compares well with standard off‐line OMI ozone products as well as ground‐based Brewer measurements. After the VFD update in May 2006, the differences with Brewer measurements are −1.0 ± 7.2 DU for Sodankylä and −0.6 ± 8.0 DU for Jokioinen. Differences to OMDOAO3 and OMTO3 products are 2.1 ± 3.3 DU and 1.6 ± 6.6 DU for Sodankylä and 1.7 ± 2.0 DU and 0.0 ± 6.1 DU for Jokioinen, respectively. Between the VFD and Brewer measured UV daily dose products the relative error is generally less than 30%, which compares well to the global off‐line OMUVB product.