Emulating lateral gravity wave propagation in a global chemistry–climate model (EMAC v2.55.2) through horizontal flux redistribution
The columnar approach of gravity wave (GW) parameterisations in weather and climate models has been identified as a potential reason for dynamical biases in middle-atmospheric dynamics. For example, GW momentum flux (GWMF) discrepancies between models and observations at 60 ∘ S arising through the l...
Published in: | Geoscientific Model Development |
---|---|
Main Authors: | , , , , , , , , |
Format: | Text |
Language: | English |
Published: |
2023
|
Subjects: | |
Online Access: | https://doi.org/10.5194/gmd-16-5561-2023 https://gmd.copernicus.org/articles/16/5561/2023/ |
id |
ftcopernicus:oai:publications.copernicus.org:gmd109680 |
---|---|
record_format |
openpolar |
spelling |
ftcopernicus:oai:publications.copernicus.org:gmd109680 2023-11-05T03:36:56+01:00 Emulating lateral gravity wave propagation in a global chemistry–climate model (EMAC v2.55.2) through horizontal flux redistribution Eichinger, Roland Rhode, Sebastian Garny, Hella Preusse, Peter Pisoft, Petr Kuchař, Aleš Jöckel, Patrick Kerkweg, Astrid Kern, Bastian 2023-10-06 application/pdf https://doi.org/10.5194/gmd-16-5561-2023 https://gmd.copernicus.org/articles/16/5561/2023/ eng eng doi:10.5194/gmd-16-5561-2023 https://gmd.copernicus.org/articles/16/5561/2023/ eISSN: 1991-9603 Text 2023 ftcopernicus https://doi.org/10.5194/gmd-16-5561-2023 2023-10-09T16:24:15Z The columnar approach of gravity wave (GW) parameterisations in weather and climate models has been identified as a potential reason for dynamical biases in middle-atmospheric dynamics. For example, GW momentum flux (GWMF) discrepancies between models and observations at 60 ∘ S arising through the lack of horizontal orographic GW propagation are suspected to cause deficiencies in representing the Antarctic polar vortex. However, due to the decomposition of the model domains onto different computing tasks for parallelisation, communication between horizontal grid boxes is computationally extremely expensive, making horizontal propagation of GWs unfeasible for global chemistry–climate simulations. To overcome this issue, we present a simplified solution to approximate horizontal GW propagation through redistribution of the GWMF at one single altitude by means of tailor-made redistribution maps. To generate the global redistribution maps averaged for each grid box, we use a parameterisation describing orography as a set of mountain ridges with specified location, orientation and height combined with a ray-tracing model describing lateral propagation of so-generated mountain waves. In the global chemistry–climate model (CCM) EMAC (ECHAM MESSy Atmospheric Chemistry), these maps then allow us to redistribute the GW momentum flux horizontally at one level, obtaining an affordable overhead of computing resources. The results of our simulations show GWMF and drag patterns that are horizontally more spread out than with the purely columnar approach; GWs are now also present above the ocean and regions without mountains. In this paper, we provide a detailed description of how the redistribution maps are computed and how the GWMF redistribution is implemented in the CCM. Moreover, an analysis shows why 15 km is the ideal altitude for the redistribution. First results with the redistributed orographic GWMF provide clear evidence that the redistributed GW drag in the Southern Hemisphere has the potential to modify and improve ... Text Antarc* Antarctic Copernicus Publications: E-Journals Geoscientific Model Development 16 19 5561 5583 |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
The columnar approach of gravity wave (GW) parameterisations in weather and climate models has been identified as a potential reason for dynamical biases in middle-atmospheric dynamics. For example, GW momentum flux (GWMF) discrepancies between models and observations at 60 ∘ S arising through the lack of horizontal orographic GW propagation are suspected to cause deficiencies in representing the Antarctic polar vortex. However, due to the decomposition of the model domains onto different computing tasks for parallelisation, communication between horizontal grid boxes is computationally extremely expensive, making horizontal propagation of GWs unfeasible for global chemistry–climate simulations. To overcome this issue, we present a simplified solution to approximate horizontal GW propagation through redistribution of the GWMF at one single altitude by means of tailor-made redistribution maps. To generate the global redistribution maps averaged for each grid box, we use a parameterisation describing orography as a set of mountain ridges with specified location, orientation and height combined with a ray-tracing model describing lateral propagation of so-generated mountain waves. In the global chemistry–climate model (CCM) EMAC (ECHAM MESSy Atmospheric Chemistry), these maps then allow us to redistribute the GW momentum flux horizontally at one level, obtaining an affordable overhead of computing resources. The results of our simulations show GWMF and drag patterns that are horizontally more spread out than with the purely columnar approach; GWs are now also present above the ocean and regions without mountains. In this paper, we provide a detailed description of how the redistribution maps are computed and how the GWMF redistribution is implemented in the CCM. Moreover, an analysis shows why 15 km is the ideal altitude for the redistribution. First results with the redistributed orographic GWMF provide clear evidence that the redistributed GW drag in the Southern Hemisphere has the potential to modify and improve ... |
format |
Text |
author |
Eichinger, Roland Rhode, Sebastian Garny, Hella Preusse, Peter Pisoft, Petr Kuchař, Aleš Jöckel, Patrick Kerkweg, Astrid Kern, Bastian |
spellingShingle |
Eichinger, Roland Rhode, Sebastian Garny, Hella Preusse, Peter Pisoft, Petr Kuchař, Aleš Jöckel, Patrick Kerkweg, Astrid Kern, Bastian Emulating lateral gravity wave propagation in a global chemistry–climate model (EMAC v2.55.2) through horizontal flux redistribution |
author_facet |
Eichinger, Roland Rhode, Sebastian Garny, Hella Preusse, Peter Pisoft, Petr Kuchař, Aleš Jöckel, Patrick Kerkweg, Astrid Kern, Bastian |
author_sort |
Eichinger, Roland |
title |
Emulating lateral gravity wave propagation in a global chemistry–climate model (EMAC v2.55.2) through horizontal flux redistribution |
title_short |
Emulating lateral gravity wave propagation in a global chemistry–climate model (EMAC v2.55.2) through horizontal flux redistribution |
title_full |
Emulating lateral gravity wave propagation in a global chemistry–climate model (EMAC v2.55.2) through horizontal flux redistribution |
title_fullStr |
Emulating lateral gravity wave propagation in a global chemistry–climate model (EMAC v2.55.2) through horizontal flux redistribution |
title_full_unstemmed |
Emulating lateral gravity wave propagation in a global chemistry–climate model (EMAC v2.55.2) through horizontal flux redistribution |
title_sort |
emulating lateral gravity wave propagation in a global chemistry–climate model (emac v2.55.2) through horizontal flux redistribution |
publishDate |
2023 |
url |
https://doi.org/10.5194/gmd-16-5561-2023 https://gmd.copernicus.org/articles/16/5561/2023/ |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
eISSN: 1991-9603 |
op_relation |
doi:10.5194/gmd-16-5561-2023 https://gmd.copernicus.org/articles/16/5561/2023/ |
op_doi |
https://doi.org/10.5194/gmd-16-5561-2023 |
container_title |
Geoscientific Model Development |
container_volume |
16 |
container_issue |
19 |
container_start_page |
5561 |
op_container_end_page |
5583 |
_version_ |
1781692251233058816 |