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A comparison of regional isentropic-sigma and sigma model simulations of the January 1979 Chicago blizzardIn an initial effort in regional numerical weather prediction, results from the University of Wisconsin isentropic-sigma (UW theta-sigma) hybrid model and an 'identical' sigma model are compared. The two main objectives are to demonstrate the capability of the UW theta-sigma model for regional numerical weather prediction and to identify advantages of the hybrid model in simulating atmospheric water vapor transport and precipitation relative to the sigma model. The 72-h simulations produced by the two models extend over a region covering the western Pacific Ocean, North America, and the western Atlantic Ocean. The simulations begin at 0000 UTC 13 January 1979, a period during which an intense Chicago blizzard develops over the central United States. This period also includes the rapid development of a cyclone in the western Pacific Ocean. Results using the Global Weather Experiment (GWE) ECMWF level IIIB data as initial and verification data indicate that both models produce reasonable and similar 72-h simulations, with the UW theta-sigma model mass and momentum distributions being slightly more accurate than the sigma model. Of particular importance for the Chicago blizzard is that the UW theta-sigma model more accurately simulates water vapor transport northward from the Gulf of Mexico and westward from the Atlantic Ocean. As a result, the hybrid model more accurately simulates observed precipitation, especially over the northeastern U.S. and southeastern Canada.
Document ID
19930064877
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Zapotocny, Tom H.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Johnson, Donald R.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Reames, Fred M.
(Wisconsin Univ. Madison, United States)
Date Acquired
August 16, 2013
Publication Date
July 1, 1993
Publication Information
Publication: Monthly Weather Review
Volume: 121
Issue: 7
ISSN: 0027-0644
Subject Category
Meteorology And Climatology
Accession Number
93A48874
Funding Number(s)
CONTRACT_GRANT: NAG5-1330
Distribution Limits
Public
Copyright
Other

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