| Home > Newsevents > Training > Rcourse_notes > DATA_ASSIMILATION > ASSIM_TECHNIQUES_4dVAR > |
Assimilation Techniques: 4dVar
April 2001
By Mike Fisher
European Centre for Medium-Range Weather
Forecasts.
Table of contents >>
Next Section >>
Previous Section >>
3 . The current operational configuration of 4dVar
The current ECMWF operational 4dVar assimilation system is as follows:
| • Outer resolution: T511 L60. |
| • Resolution of increments: T159 L60 |
| • Two incremental updates: |
| • First update: 50 iterations with very simple physical parameterizations. |
| • Second update: 25 iterations with comprehensive physics. |
| • Physical parameterizations during the second update: |
| • Vertical diffusion. |
| • Sub-grid scale orographic drag. |
| • Large scale precipitation. |
| • Longwave radiation. |
| • Deep moist convection. |
| • Separate analyses of some surface quantities (sea ice, sea surface termperature, soil wetness, snow, 2m temperature and 2m humidity). |
Training Course Notes Front Page >>
Table of contents >>
Next Section >>
Previous Section >>
 |
06.06.2002 |
 |
© ECMWF |
