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| Titel |
Mass-conserving tracer transport modelling on a reduced latitude-longitude grid with NIES-TM |
| VerfasserIn |
D. Belikov, S. Maksyutov, T. Miyasaka, T. Saeki, R. Zhuravlev, B. Kiryushov |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1991-959X
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| Digitales Dokument |
URL |
| Erschienen |
In: Geoscientific Model Development ; 4, no. 1 ; Nr. 4, no. 1 (2011-03-22), S.207-222 |
| Datensatznummer |
250001562
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| Publikation (Nr.) |
 copernicus.org/gmd-4-207-2011.pdf |
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| Zusammenfassung |
| The need to perform long-term simulations with reasonable accuracy has led
to the development of mass-conservative and efficient numerical methods for
solving the transport equation in forward and inverse models. We designed
and implemented a flux-form (Eulerian) tracer transport algorithm in the
National Institute for Environmental Studies Transport Model (NIES TM),
which is used for simulating diurnal and synoptic-scale variations of
tropospheric long-lived constituents, as well as their seasonal and
inter-annual variability. Implementation of the flux-form method requires
the mass conservative wind fields. However, the model is off-line and is
driven by datasets from a global atmospheric model or data assimilation
system, in which vertically integrated mass changes are not in balance with
the surface pressure tendency and mass conservation is not achieved. To
rectify the mass-imbalance, a flux-correction method is employed. To avoid a
singularity near the poles, caused by the small grid size arising from the
meridional convergence problem, the proposed model uses a reduced
latitude–longitude grid scheme, in which the grid size is doubled several
times approaching the poles. This approach overcomes the Courant condition
in the Polar Regions, maintains a reasonably high integration time-step, and
ensures adequate model performance during simulations. To assess the model
performance, we performed global transport simulations for SF6,
222Rn, and CO2. The results were compared with observations
available from the World Data Centre for Greenhouse Gases, GLOBALVIEW, and
the Hateruma monitoring station, Japan. Overall, the results show that the
proposed flux-form version of NIES TM can produce tropospheric tracer
transport more realistically than previously possible. The reasons for this
improvement are discussed. |
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