 |
| Titel |
Forecasts covering one month using a cut-cell model |
| VerfasserIn |
J. Steppeler, S.-H. Park, A. Dobler |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1991-959X
|
| Digitales Dokument |
URL |
| Erschienen |
In: Geoscientific Model Development ; 6, no. 4 ; Nr. 6, no. 4 (2013-07-03), S.875-882 |
| Datensatznummer |
250017853
|
| Publikation (Nr.) |
 copernicus.org/gmd-6-875-2013.pdf |
|
|
|
|
|
| Zusammenfassung |
| This paper investigates the impact and potential use of the cut-cell
vertical discretisation for forecasts covering five days and climate
simulations. A first indication of the usefulness of this new method
is obtained by a set of five-day forecasts, covering January 1989 with
six forecasts. The model area was chosen to include much of Asia, the
Himalayas and Australia. The cut-cell model LMZ (Lokal Modell with z-coordinates) provides a much more
accurate representation of mountains on model forecasts than the
terrain-following coordinate used for comparison. Therefore we are
in particular interested in potential forecast improvements in the
target area downwind of the Himalayas, over southeastern China, Korea
and Japan. The LMZ has previously been tested extensively for one-day
forecasts on a European area. Following indications of a reduced
temperature error for the short forecasts, this paper investigates
the model error for five days in an area influenced by strong
orography. The forecasts indicated a strong impact of the cut-cell
discretisation on forecast quality. The cut-cell model is available
only for an older (2003) version of the model LM (Lokal Modell). It was compared
using a control model differing by the use of the terrain-following
coordinate only. The cut-cell model improved the precipitation
forecasts of this old control model everywhere by a large margin. An
improved, more transferable version of the terrain-following model LM has been
developed since then under the name CLM (Climate version of the Lokal Modell). The CLM has been used and
tested in all climates, while the LM was used for small areas in
higher latitudes. The precipitation forecasts of the cut-cell model were
compared also to the CLM. As the cut-cell model LMZ did not
incorporate the developments for CLM since 2003, the precipitation
forecast of the CLM was not improved in all aspects. However, for
the target area downstream of the Himalayas, the cut-cell model
considerably improved the prediction of the monthly precipitation forecast even
in comparison with the modern CLM version. The
cut-cell discretisation seems to improve in particular the
localisation of precipitation, while the improvements leading from
LM to CLM had a positive effect mainly on amplitude. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|