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Next generation initiation techniquesFour-dimensional data assimilation strategies can generally be classified as either current or next generation, depending upon whether they are used operationally or not. Current-generation data-assimilation techniques are those that are presently used routinely in operational-forecasting or research applications. They can be classified into the following categories: intermittent assimilation, Newtonian relaxation, and physical initialization. It should be noted that these techniques are the subject of continued research, and their improvement will parallel the development of next generation techniques described by the other speakers. Next generation assimilation techniques are those that are under development but are not yet used operationally. Most of these procedures are derived from control theory or variational methods and primarily represent continuous assimilation approaches, in which the data and model dynamics are 'fitted' to each other in an optimal way. Another 'next generation' category is the initialization of convective-scale models. Intermittent assimilation systems use an objective analysis to combine all observations within a time window that is centered on the analysis time. Continuous first-generation assimilation systems are usually based on the Newtonian-relaxation or 'nudging' techniques. Physical initialization procedures generally involve the use of standard or nonstandard data to force some physical process in the model during an assimilation period. Under the topic of next-generation assimilation techniques, variational approaches are currently being actively developed. Variational approaches seek to minimize a cost or penalty function which measures a model's fit to observations, background fields and other imposed constraints. Alternatively, the Kalman filter technique, which is also under investigation as a data assimilation procedure for numerical weather prediction, can yield acceptable initial conditions for mesoscale models. The third kind of next-generation technique involves strategies to initialize convective scale (non-hydrostatic) models.
Document ID
19940019910
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Warner, Tom
(Pennsylvania State Univ. University Park., United States)
Derber, John
(National Meteorological Center Camp Springs, MD., United States)
Zupanski, Milija
(National Meteorological Center Camp Springs, MD., United States)
Cohn, Steve
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Verlinde, Hans
(Colorado State Univ. Fort Collins., United States)
Date Acquired
September 6, 2013
Publication Date
June 1, 1993
Publication Information
Publication: Report of the Proceedings of the Colloquium and Workshop on Multiscale Coupled Modeling
Subject Category
Meteorology And Climatology
Accession Number
94N24383
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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