2.1
Beyond ERBE: A CERES Radiation Data Overview
Bruce A. Wielicki, NASA/LARC, Hampton, VA; and C. Science Team
A new generation of radiation budget data has recently become available to the radiation sciences community. This paper will give a brief overview of the major advances, which products are available, where to find both these products and the documentation that describes their accuracy, as well as the schedule for delivery of new products. There are several major advances over ERBE in the new data products that include: improved calibration accuracy and stability (factor of 2 to 4), a new generation of observed angular dependence models (factor of 2 to 10), merging of 3-hourly geostationary diurnal cycles with broadband data (factor of 2 to 4), improved estimates of surface and within atmosphere radiative fluxes constrained for each CERES field of view against the more accurate TOA flux data. Even more important for new studies attempting to unscramble the role of aerosols and clouds in the climate system, the new data products integrate imager based surface, aerosol and cloud property estimates with each CERES field of view, and along with the ECMWF 4-D assimilation data, develop the most consistent picture of the radiation fields yet available. Validation is performed using long time series of satellite overflights of surface validation sites such as ARM and BSRN, as well as a wide range of internal consistency checks between CERES observations at multiple angles, times, spectral bands, and instruments.
This overview will set the stage for a range of more specific CERES papers that describe the advances in each area, and provide users with an understanding of the accuracy and remaining limitations in the new generation of radiation data products. These products began with the delivery of the new angular dependence models in September 2001 for over 200 clear and cloudy scene types from TRMM using the new CERES Rotating Azimuth Plane data that can sample the entire hemisphere of radiation. These new models were then used to provide more accurate TOA fluxes merged with surface, aerosol, and cloud data for each CERES field of view in the SSF data product available from TRMM starting in October 2001. Unlike ERBE, the new angular models provide TOA fluxes that are accurate for a wide range of cloud conditions, not just monthly mean regional composites of all clouds. These new SSF fluxes will be used to constrain new surface and atmospheric radiative flux estimates in the CRS data product available April, 2002 just before the Radiation Conference. The new time averaged (daily, monthly) products that incorporate geostationary diurnal cycles will become available in April and August of 2002. Examples of data from the new data products will be shown, along with an indication of new types of studies enabled by these products.
These new products are very different from earlier ERBE-Like data products, and begin a new era of radiation data. We expect these new products to impact studies of aerosol radiative forcing, cloud and clear-sky solar absorption, the role of clouds in climate feedback, and to provide more rigorous tests of clouds and radiation in climate models.
Session 2, Earth Radiation Budget and Climate
Tuesday, 4 June 2002, 8:30 AM-11:59 AM
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