2002 Annual

Monday, 14 January 2002
1D Variational assimilation of cloud- and land-affected TOVS/ATOVS level 1b data and preparation for AIRS
Joanna Joiner, NASA/GSFC, Greenbelt, MD; and A. da Silva and D. Frank
Recently, it has been shown that the use of observations from satellite-borne microwave and infrared radiometers in data assimilation systems consistently increases forecast skill. Considerable effort has been expended over the past two decades, particularly with the TIROS Operational Vertical Sounder (TOVS), to achieve this result. Despite these advances, there are still many issues regarding the use of satellite data in data assimilation systems that remain unresolved. For example, at several centers, cloud- and land-affected TOVS data are not assimilated. In this study, we show positive impact from the use of cloud-cleared and land-affected TOVS data in the Data Assimilation Office's Finite-Volume Data Assimilation System (FV-DAS).

The Atmospheric InfraRed Sounder (AIRS), to be launched about NASA's Earth Observing System Aqua satellite, will be the first of the next generation kilo-channel sounders. Methods of data compression for data assimilation and transmission include channel decimation and empirical orthogonal function or principle component compression. These are currently under consideration due to the computational limitations of current data assimilation systems. We will show how a dynamic channel selection for AIRS based on a cloud height retrieval will potentially benefit its use in data assimilation systems.

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