2002 Annual

Tuesday, 15 January 2002: 9:15 AM
Assimilation of HRDI Line-of-Sight Winds
Andrew V. Tangborn, NASA/GSFC, Greenbelt, MD; and R. Menard and D. Ortland
Poster PDF (265.8 kB)
The High Resolution Doppler Imager (HRDI), on board the Upper Atmosphere Research Satellite (UARS) provides direct global-scale measurements of the stratospheric and upper tropospheric wind field (10-40 km). We have incorporated these observations into the GEOS-DAS assimilation system and present here initial results on the impact of these observations on the stratospheric wind analyses. While the HRDI observations are noisy, they can be separated by observational parameters (eg absorption band), and the observation errors for some data subsets have substantially smaller errors. These subsets are used in carrying out the assimilations. Direct validation is done using aircraft zonal winds between 100 and 500 mbar, where we find reduction in mean errors at most levels.

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