Improving a global model from the boundary layer: total turbulent energy and the neutral limit Prandtl number
Model intercomparisons have identified important deficits in the representation of the stable boundary layer by turbulence parametrizations used in current weather and climate models. However, detrimental impacts of more realistic schemes on the large-scale flow have hindered progress in this area....
Published in: | Journal of Advances in Modeling Earth Systems |
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American Geophysical Union
2015
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ftunivreading:oai:centaur.reading.ac.uk:43568 2024-09-15T18:37:13+00:00 Improving a global model from the boundary layer: total turbulent energy and the neutral limit Prandtl number Pithan, Felix Angevine, Wayne Mauritsen, Thorsten 2015-05-31 text https://centaur.reading.ac.uk/43568/ https://centaur.reading.ac.uk/43568/1/jame20172.pdf en eng American Geophysical Union https://centaur.reading.ac.uk/43568/1/jame20172.pdf Pithan, F. <https://centaur.reading.ac.uk/view/creators/90005860.html>, Angevine, W. and Mauritsen, T. (2015) Improving a global model from the boundary layer: total turbulent energy and the neutral limit Prandtl number. Journal of Advances in Modeling Earth Systems, 7 (2). pp. 791-805. ISSN 1942-2466 doi: https://doi.org/10.1002/2014MS000382 <https://doi.org/10.1002/2014MS000382> cc_by_nc_nd Article PeerReviewed 2015 ftunivreading https://doi.org/10.1002/2014MS000382 2024-06-25T14:58:45Z Model intercomparisons have identified important deficits in the representation of the stable boundary layer by turbulence parametrizations used in current weather and climate models. However, detrimental impacts of more realistic schemes on the large-scale flow have hindered progress in this area. Here we implement a total turbulent energy scheme into the climate model ECHAM6. The total turbulent energy scheme considers the effects of Earth’s rotation and static stability on the turbulence length scale. In contrast to the previously used turbulence scheme, the TTE scheme also implicitly represents entrainment flux in a dry convective boundary layer. Reducing the previously exaggerated surface drag in stable boundary layers indeed causes an increase in southern hemispheric zonal winds and large-scale pressure gradients beyond observed values. These biases can be largely removed by increasing the parametrized orographic drag. Reducing the neutral limit turbulent Prandtl number warms and moistens low-latitude boundary layers and acts to reduce longstanding radiation biases in the stratocumulus regions, the Southern Ocean and the equatorial cold tongue that are common to many climate models. Article in Journal/Newspaper Southern Ocean CentAUR: Central Archive at the University of Reading Journal of Advances in Modeling Earth Systems 7 2 791 805 |
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Open Polar |
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CentAUR: Central Archive at the University of Reading |
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ftunivreading |
language |
English |
description |
Model intercomparisons have identified important deficits in the representation of the stable boundary layer by turbulence parametrizations used in current weather and climate models. However, detrimental impacts of more realistic schemes on the large-scale flow have hindered progress in this area. Here we implement a total turbulent energy scheme into the climate model ECHAM6. The total turbulent energy scheme considers the effects of Earth’s rotation and static stability on the turbulence length scale. In contrast to the previously used turbulence scheme, the TTE scheme also implicitly represents entrainment flux in a dry convective boundary layer. Reducing the previously exaggerated surface drag in stable boundary layers indeed causes an increase in southern hemispheric zonal winds and large-scale pressure gradients beyond observed values. These biases can be largely removed by increasing the parametrized orographic drag. Reducing the neutral limit turbulent Prandtl number warms and moistens low-latitude boundary layers and acts to reduce longstanding radiation biases in the stratocumulus regions, the Southern Ocean and the equatorial cold tongue that are common to many climate models. |
format |
Article in Journal/Newspaper |
author |
Pithan, Felix Angevine, Wayne Mauritsen, Thorsten |
spellingShingle |
Pithan, Felix Angevine, Wayne Mauritsen, Thorsten Improving a global model from the boundary layer: total turbulent energy and the neutral limit Prandtl number |
author_facet |
Pithan, Felix Angevine, Wayne Mauritsen, Thorsten |
author_sort |
Pithan, Felix |
title |
Improving a global model from the boundary layer: total turbulent energy and the neutral limit Prandtl number |
title_short |
Improving a global model from the boundary layer: total turbulent energy and the neutral limit Prandtl number |
title_full |
Improving a global model from the boundary layer: total turbulent energy and the neutral limit Prandtl number |
title_fullStr |
Improving a global model from the boundary layer: total turbulent energy and the neutral limit Prandtl number |
title_full_unstemmed |
Improving a global model from the boundary layer: total turbulent energy and the neutral limit Prandtl number |
title_sort |
improving a global model from the boundary layer: total turbulent energy and the neutral limit prandtl number |
publisher |
American Geophysical Union |
publishDate |
2015 |
url |
https://centaur.reading.ac.uk/43568/ https://centaur.reading.ac.uk/43568/1/jame20172.pdf |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_relation |
https://centaur.reading.ac.uk/43568/1/jame20172.pdf Pithan, F. <https://centaur.reading.ac.uk/view/creators/90005860.html>, Angevine, W. and Mauritsen, T. (2015) Improving a global model from the boundary layer: total turbulent energy and the neutral limit Prandtl number. Journal of Advances in Modeling Earth Systems, 7 (2). pp. 791-805. ISSN 1942-2466 doi: https://doi.org/10.1002/2014MS000382 <https://doi.org/10.1002/2014MS000382> |
op_rights |
cc_by_nc_nd |
op_doi |
https://doi.org/10.1002/2014MS000382 |
container_title |
Journal of Advances in Modeling Earth Systems |
container_volume |
7 |
container_issue |
2 |
container_start_page |
791 |
op_container_end_page |
805 |
_version_ |
1810481572460101632 |