Tuesday, 15 January 2002: 9:15 AM
Assimilation of HRDI Line-of-Sight Winds
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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