20th International Conference on Interactive Information and Processing Systems (IIPS) for Meteorology, Oceanography, and Hydrology


Clear Sky GAC Radiation Budget Product System at NESDIS

David R. Donahue, Science and Technology Corporation, Suitland, MD; and J. Sapper and V. Kapoor

The effect of clouds on the radiative fluxes at the top of the atmosphere (TOA) has become increasingly important for studying climate. One useful way for quantifying this effect is by determining what is generally referred to as "cloud radiative forcing", which is often defined as the difference in the TOA flux between the cloudy and clear-sky atmosphere. To develop a clear-sky retrieval system, clouds from the AVHRR version 1 (CLAVR-1) software was set up to run on one of the IPD development platforms. This software reads a NOAA-16 GAC 1B, uses a cloud mask decision tree, and outputs a "1C" file that contains the CLAVR-1 cloud mask information. The existing all-sky radiation budget software was modified to compute clear-sky longwave and shortwave retrievals using the CLAVR-1 cloud mask information to tag clear and cloudy GAC pixels within an 11x11 retrieval target, as well as determine the target scene type. In post orbital gridded analysis processing, the clear retrievals are binned into an equal area grid and further averaged with other clear-sky fluxes in the same bin. Orbital and gridded images of clear sky radiation budget products are displayed via the Web along with their all sky counterparts. Subtracting the clear sky from the all sky product produces a measure of the cloud radiative forcing. Work is currently underway to replace the CLAVR-1 system with CLAVR-x. The CLAVR-x system writes cloud mask information back to the AVHRR 1B level file and will make production of clear sky retrievals possible for all satellites with AVHRR. The purpose of this paper is to present the status of near-realtime clear sky products that are currently available to the user community.

extended abstract  Extended Abstract (1.2M)

Session 16, Satellite IIPS and Applications Part II (ROOM 6B)
Thursday, 15 January 2004, 8:30 AM-11:45 AM, Room 6B

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