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A preliminary study of the impact of the ERS 1 C band scatterometer wind data on the European Centre for Medium-Range Weather Forecasts global data assimilation systemA preliminary assessment of the impact of the ERS 1 scatterometer wind data on the current European Centre for Medium-Range Weather Forecasts analysis and forecast system has been carried out. Although the scatterometer data results in changes to the analyses and forecasts, there is no consistent improvement or degradation. Our results are based on comparing analyses and forecasts from assimilation cycles. The two sets of analyses are very similar except for the low level wind fields over the ocean. Impacts on the analyzed wind fields are greater over the southern ocean, where other data are scarce. For the most part the mass field increments are too small to balance the wind increments. The effect of the nonlinear normal mode initialization on the analysis differences is quite small, but we observe that the differences tend to wash out in the subsequent 6-hour forecast. In the Northern Hemisphere, analysis differences are very small, except directly at the scatterometer locations. Forecast comparisons reveal large differences in the Southern Hemisphere after 72 hours. Notable differences in the Northern Hemisphere do not appear until late in the forecast. Overall, however, the Southern Hemisphere impacts are neutral. The experiments described are preliminary in several respects. We expect these data to ultimately prove useful for global data assimilation.
Document ID
19930061897
Document Type
Reprint (Version printed in journal)
Authors
Hoffman, Ross N. (Atmospheric and Environmental Research, Inc. Cambridge, MA, United States)
Date Acquired
August 16, 2013
Publication Date
June 15, 1993
Publication Information
Publication: Journal of Geophysical Research
Volume: 98
Issue: C6
ISSN: 0148-0227
Subject Category
METEOROLOGY AND CLIMATOLOGY
Funding Number(s)
CONTRACT_GRANT: JPL-957644
CONTRACT_GRANT: NAS7-918
Distribution Limits
Public
Copyright
Other