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An Optimised Method to Couple Meteorological and Photochemical Models for Air Quality Applications
| Content Provider | Semantic Scholar |
|---|---|
| Copyright Year | 2003 |
| Abstract | Air quality numerical studies require coupling of meteorological and photochemical forecast. Most of the time, this coupling is realised in a non-simultaneous way, i.e. first a meteorology model is run, data are stored, and photo-chemistry is simulated. This study shows that significant errors may be generated in gas-phase photochemical modeling if meteorological field update intervals are too coarse to resolve wind-field time variations. Three different coupling methods are compared. Differences between a decoupled method using hourly updates and a fully coupled calculation, are shown to be on the same order of magnitude as the disagreement between observations and model predictions in current applications. A socalled hybrid method in which meteorology updates are performed after a well defined time lag (CFL limit, i.e. few minutes) is presented and is shown to be a good compromise between the full coupled (updates based on the time step of the meteorological resolution, i.e. each 20s) and decoupled (hourly updates) methods. Indeed this hybrid method keeps a level of accuracy very close to full coupling while CPU time is kept similar to the decoupled method. The impact of different transport time step on the accuracy of the results is also investigated. Concentrations resulting from three different time-steps calculations are compared showing that smaller transport time steps significantly improve results for the hybrid method but only slightly for the decoupled method. Section 3: An optimised method... 3.2 |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://lpas.epfl.ch/MOD/publi/pdf-Clappier/chap3.pdf |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | 20s CPU (central processing unit of computer system) Central processing unit Courant–Friedrichs–Lewy condition Cure for Lymphoma Foundation Horner's method Numerical analysis Projections and Predictions Small |
| Content Type | Text |
| Resource Type | Article |
