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The control of gravity waves
in data assimilation
27 April 1999
By Adrian
Simmons
European Centre for Medium-Range Weather
Forecasts
| DATA ASSIMILATION | |||||||||
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Abstract
The need to control gravity waves in data assimilation
and the general concept of initialization are discussed. The basic method
of non-linear normal-mode initialization is introduced, and aspects of
its implementation in models are presented, covering the vertical and
horizontal modal decomposition, implicit initialization and diabatic initialization.
The control of gravity waves in the ECMWF variational data assimilation
system is described. An introduction to the alternative method of digital
filtering is also given.
Table of contents
2 . Non-linear normal-mode initialization
| 2.1 Basic method |
| 2.2 Vertical decomposition |
| 2.3 Horizontal decomposition |
| 2.4 Implicit initialization |
| 2.5 Diabatic initialization |
3 . Control of gravity waves in the ECMWF variational data assimilation system
4 . Digital filtering
| 4.1 Adiabatic, non-recursive filtering |
| 4.2 Diabatic, recursive filtering |
| 4.3 Diabatic, non-recursive filtering |
APPENDIX A . Definition of operators for the ECMWF vertical finite-difference scheme
APPENDIX B . The Lamb Wave
APPENDIX C . The non-recursive implementation of the recursive filter
References
Training Course Notes Front Page >>
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