A comparison of two initialization methods in data assimilation
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Authors
Barker, Edward Harrison
Subjects
Numerical weather prediction
Data assimilation
Initialization
Objective analysis
Data assimilation
Initialization
Objective analysis
Advisors
Haltiner, G.J.
Date of Issue
1982-06
Date
June 1992
Publisher
Language
en_US
Abstract
Two different initialization methods were developed and tested in global data assimilation experiments covering a five-day period. One method was based on the nonlinear normal mode initialization, and the other was based on the balance equation. Both techniques were developed using the calculus of variations methodology. in both methods, the initial divergence was computed from the forecast first-guess fields, except that it was partially modified in the nonlinear normal mode method to improve the balance. The assimilation system used to test the initialization methods was developed for the global forecast model at the Fleet Numerical Oceanography Center. This model was adapted from the general circulation model developed at the University of California at los Angeles. A comparison of the gravity wave noise from the two models is given for versions of the model with and without heating. Other comparisons are given for divergence, precipitation rates, wave structure and cyclogenesis. The two methods are similar in their performance in data assimilation. The balance equation method is more flexible in weight specification and, consequently to forecasts verify with observations closer than the normal mode method.
Type
Thesis
Description
Series/Report No
Department
Department of Meteorology
Organization
Naval Postgraduate School (U.S.)
Identifiers
NPS Report Number
Sponsors
Funder
Format
Citation
Distribution Statement
Approved for public release; distribution is unlimited.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.