The FRESCO (Fast Retrieval Scheme for Clouds from the Oxygen A-band) algorithm has been success-fully used in GOME and SCIAMACHY cloud retrieval for several years. It simulates the measured reflectance at TOA at 15 wavelengths at about 758, 761, and 765 nm. The reflectances are pre-calculated, and stored as a look-up-table. The FRESCO products are effective cloud fraction and cloud pressure, which are used in the cloud correction of trace gas retrievals from GOME and SCIAMACHY. Until now only O2 absorption has been considered in FRESCO. In the new version of the FRESCO algorithm, called FRESCO+, single Rayleigh scattering is added in the reflectance database and the retrieval. Rayleigh scattering is mainly important for the cloud free part of the pixels. The new reflectance database has been tested with DAK (Doubling Adding KNMI) multiple scattering simulations of the O2 A-band. Applied to GOME data, FRESCO+ gives a global average effective cloud fraction which is about 0.01 larger and a cloud pressure which is about 57 hPa higher than the current FRESCO version. The cloud pressure changes are largest for the less cloudy pixels. The FRESCO+ cloud height has been compared with ground-based cloud observations from the SGP/ARM site.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.