Modeling stable orographic precipitation at small scales: The impact of the autoconversion scheme
This study presents idealized numerical simulations of moist airflow over a narrow isolated mountain in order to investigate the impact of the autoconversion scheme on simulated precipitation. The default setup generates an isolated water cloud over the mountain, implying that autoconversion of clou...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Borntraeger
2010-10-01
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| Series: | Meteorologische Zeitschrift |
| Online Access: | http://dx.doi.org/10.1127/0941-2948/2010/0458 |
| _version_ | 1797332601293242368 |
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| author | Günther Zängl Axel Seifert Wolfram Wobrock |
| author_facet | Günther Zängl Axel Seifert Wolfram Wobrock |
| author_sort | Günther Zängl |
| collection | DOAJ |
| description | This study presents idealized numerical simulations of moist airflow over a narrow isolated mountain in order to investigate the impact of the autoconversion scheme on simulated precipitation. The default setup generates an isolated water cloud over the mountain, implying that autoconversion of cloud water into rain is the only process capable of initiating precipitation. For comparison, a set of sensitivity experiments considers the classical seeder-feeder configuration, which means that ambient precipitation generated by large-scale lifting is intensified within the orographic cloud. Most simulations have been performed with the nonhydrostatic COSMO model developed at the German Weather Service (DWD), comparing three different autoconversion schemes of varying sophistication. For reference, a subset of experiments has also been performed with a spectral (bin) microphysics model. While precipitation enhancement via the seeder-feeder mechanism turns out to be relatively insensitive against the autoconversion scheme because accretion is the leading process in this case, simulated precipitation amounts can vary by 1-2 orders of magnitude for purely orographic precipitation. By comparison to the reference experiments conducted with the bin model, the Seifert-Beheng autoconversion scheme (which is the default in the COSMO model) and the Berry-Reinhardt scheme are found to represent the nonlinear behaviour of orographic precipitation reasonably well, whereas the linear approach of the Kessler scheme appears to be less adequate. |
| first_indexed | 2024-03-08T07:52:13Z |
| format | Article |
| id | doaj.art-d146286882bf4bd4b14889edc9c28605 |
| institution | Directory Open Access Journal |
| issn | 0941-2948 |
| language | English |
| last_indexed | 2024-03-08T07:52:13Z |
| publishDate | 2010-10-01 |
| publisher | Borntraeger |
| record_format | Article |
| series | Meteorologische Zeitschrift |
| spelling | doaj.art-d146286882bf4bd4b14889edc9c286052024-02-02T14:43:58ZengBorntraegerMeteorologische Zeitschrift0941-29482010-10-0119540541610.1127/0941-2948/2010/045875352Modeling stable orographic precipitation at small scales: The impact of the autoconversion schemeGünther ZänglAxel SeifertWolfram WobrockThis study presents idealized numerical simulations of moist airflow over a narrow isolated mountain in order to investigate the impact of the autoconversion scheme on simulated precipitation. The default setup generates an isolated water cloud over the mountain, implying that autoconversion of cloud water into rain is the only process capable of initiating precipitation. For comparison, a set of sensitivity experiments considers the classical seeder-feeder configuration, which means that ambient precipitation generated by large-scale lifting is intensified within the orographic cloud. Most simulations have been performed with the nonhydrostatic COSMO model developed at the German Weather Service (DWD), comparing three different autoconversion schemes of varying sophistication. For reference, a subset of experiments has also been performed with a spectral (bin) microphysics model. While precipitation enhancement via the seeder-feeder mechanism turns out to be relatively insensitive against the autoconversion scheme because accretion is the leading process in this case, simulated precipitation amounts can vary by 1-2 orders of magnitude for purely orographic precipitation. By comparison to the reference experiments conducted with the bin model, the Seifert-Beheng autoconversion scheme (which is the default in the COSMO model) and the Berry-Reinhardt scheme are found to represent the nonlinear behaviour of orographic precipitation reasonably well, whereas the linear approach of the Kessler scheme appears to be less adequate.http://dx.doi.org/10.1127/0941-2948/2010/0458 |
| spellingShingle | Günther Zängl Axel Seifert Wolfram Wobrock Modeling stable orographic precipitation at small scales: The impact of the autoconversion scheme Meteorologische Zeitschrift |
| title | Modeling stable orographic precipitation at small scales: The impact of the autoconversion scheme |
| title_full | Modeling stable orographic precipitation at small scales: The impact of the autoconversion scheme |
| title_fullStr | Modeling stable orographic precipitation at small scales: The impact of the autoconversion scheme |
| title_full_unstemmed | Modeling stable orographic precipitation at small scales: The impact of the autoconversion scheme |
| title_short | Modeling stable orographic precipitation at small scales: The impact of the autoconversion scheme |
| title_sort | modeling stable orographic precipitation at small scales the impact of the autoconversion scheme |
| url | http://dx.doi.org/10.1127/0941-2948/2010/0458 |
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