THREE YEARS OF ENVISAT SYNERGETIC AEROSOL RETRIEVAL

At DLR-DFD a synergetic aerosol retrieval method SYNAER [1, 2] was developed, which exploits the complementary information content of the radiometer AATSR and the spectrometer SCIAMACHY, both onboard ENVISAT. This combination of two instruments allows to retrieve aerosol optical depth at 550 nm and aerosol speciation from a choice of pre-defined aerosol types. In the meantime, 3 years of ENVISAT AATSR and SCIAMACHY level 1 nadir data have been acquired (2003-2005). Processing of these data over the MSG field of view (Europe, Africa, Atlantic) has been started within the ESA GSE project PROMOTE, where SYNAER contributes to the air quality monitoring service. SYNAER products are provided daily in near-real time since June 2005 as input for data assimilation into chemistry transport models, and as long-term evolving archive. It is the goal of this paper to summarize the current status and results of this monitoring effort. The presented results range from examples of individual daily datasets to monthly mean maps. Whereas the daily datasets exhibit large data gaps due to the san patterns of the synergetic sensor pair (SCIAMACHY nadir limb switching, AATSR swath width) and cloudiness, the monthly mean datasets provide reduced temporal resolution, which is not sufficient for near-real time purposes. The mid-term perspective for the SYNAER products promises a long-term dataset ranging from 1995 with ERS-2 (ATSR-2 and GOME) to 2020 with METOP (AVHRR and GOME-2), as the algorithm development was always focused on applicability to all these 3 platforms (thus not using special features as e.g. SCIAMCHY mid infrared channels or ATSR dual view)