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Short-range precipitation forecasts using assimilation of simulated satellite water vapor profiles and column cloud liquid water amountsThese observing system simulation experiments investigate the assimilation of satellite-observed water vapor and cloud liquid water data in the initialization of a limited-area primitive equations model with the goal of improving short-range precipitation forecasts. The assimilation procedure presented includes two aspects: specification of an initial cloud liquid water vertical distribution and diabatic initialization. The satellite data is simulated for the next generation of polar-orbiting satellite instruments, the Advanced Microwave Sounding Unit (AMSU) and the High-Resolution Infrared Sounder (HIRS), which are scheduled to be launched on the NOAA-K satellite in the mid-1990s. Based on cloud-top height and total column cloud liquid water amounts simulated for satellite data a diagnostic method is used to specify an initial cloud water vertical distribution and to modify the initial moisture distribution in cloudy areas. Using a diabatic initialization procedure, the associated latent heating profiles are directly assimilated into the numerical model. The initial heating is estimated by time averaging the latent heat release from convective and large-scale condensation during the early forecast stage after insertion of satellite-observed temperature, water vapor, and cloud water formation. The assimilation of satellite-observed moisture and cloud water, together withy three-mode diabatic initialization, significantly alleviates the model precipitation spinup problem, especially in the first 3 h of the forecast. Experimental forecasts indicate that the impact of satellite-observed temperature and water vapor profiles and cloud water alone in the initialization procedure shortens the spinup time for precipitation rates by 1-2 h and for regeneration of the areal coverage by 3 h. The diabatic initialization further reduces the precipitation spinup time (compared to adiabatic initialization) by 1 h.
Document ID
19950040909
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Wu, Xiaohua
(Univ. of Wisconsin, Madison, WI United States)
Diak, George R.
(Univ. of Wisconsin, Madison, WI United States)
Hayden, Cristopher M.
(Univ. of Wisconsin, Madison, WI United States)
Young, John A.
(Univ. of Wisconsin, Madison, WI United States)
Date Acquired
August 16, 2013
Publication Date
February 1, 1995
Publication Information
Publication: Monthly Weather Review
Volume: 123
Issue: 2
ISSN: 0027-0644
Subject Category
Meteorology And Climatology
Accession Number
95A72508
Funding Number(s)
CONTRACT_GRANT: NOAA-NA17EC0427
CONTRACT_GRANT: NAG8-927
Distribution Limits
Public
Copyright
Other

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