High-Resolution Aerosol Maps Exploiting the Synergy of ATSR-2 and GOME

Abstract

Currently operational satellite observation of aerosols is limited to either the oceans or over land to high reaching or UV-absorbing aerosols with reduced horizontal resolution. To overcome these restrictions the new aerosol retrieval method SYNAER (SYNergetic AErosol Retrieval) was developed within the ESA-AO2 project PAGODA (Project for ATSR and GOME Data Application). SYNAER delivers boundary layer aerosol optical thickness (BLAOT) and type over both land and ocean, the latter as BLAOT percentage contribution of 10 representative components from the OPAC (Optical Parameters of Aerosols and Clouds) dataset. The high spatial resolution of ATSR-2 permits cloud detection, BLAOT calculation over automatically selected dark pixels and surface albedo correction for a set of different boundary layer aerosol mixtures. After spatial integration to GOME pixels these parameters are used to simulate GOME spectra for the same set of different aerosol mixtures. A least square fit of these spectra to the measured spectrum delivers the BLAOT value and - if a uniqueness test is passed - the aerosol mixture. By a feedback of the most frequent type of aerosol in GOME pixels within an ATSR-2 frame to the ATSR-2 optical thickness values high resolution aerosol maps are produced. Within the ESA-AO3 project PAGODA-2 (Extending the Applicability of New Methods from PAGODA) SYNAER is currently being validated and further extended. First case studies using ground based sun-photometer measurements of the spectral aerosol optical thickness from NASA's Aerosol Robotic Network (AERONET) show a good agreement.