Effectiveness and limitations of parameter tuning in reducing biases of top-of-atmosphere radiation and clouds in MIROC version 5
This study discusses how much of the biases in top-of-atmosphere (TOA) radiation and clouds can be removed by parameter tuning in the present-day simulation of a climate model in the Coupled Model Inter-comparison Project phase 5 (CMIP5) generation. We used output of a perturbed parameter ensemble (...
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ftdoajarticles:oai:doaj.org/article:31fff4b4da5e461ca8794fd92c3dfa52 2023-05-15T13:11:58+02:00 Effectiveness and limitations of parameter tuning in reducing biases of top-of-atmosphere radiation and clouds in MIROC version 5 T. Ogura H. Shiogama M. Watanabe M. Yoshimori T. Yokohata J. D. Annan J. C. Hargreaves N. Ushigami K. Hirota Y. Someya Y. Kamae H. Tatebe M. Kimoto 2017-12-01T00:00:00Z https://doi.org/10.5194/gmd-10-4647-2017 https://doaj.org/article/31fff4b4da5e461ca8794fd92c3dfa52 EN eng Copernicus Publications https://www.geosci-model-dev.net/10/4647/2017/gmd-10-4647-2017.pdf https://doaj.org/toc/1991-959X https://doaj.org/toc/1991-9603 doi:10.5194/gmd-10-4647-2017 1991-959X 1991-9603 https://doaj.org/article/31fff4b4da5e461ca8794fd92c3dfa52 Geoscientific Model Development, Vol 10, Pp 4647-4664 (2017) Geology QE1-996.5 article 2017 ftdoajarticles https://doi.org/10.5194/gmd-10-4647-2017 2022-12-31T14:19:57Z This study discusses how much of the biases in top-of-atmosphere (TOA) radiation and clouds can be removed by parameter tuning in the present-day simulation of a climate model in the Coupled Model Inter-comparison Project phase 5 (CMIP5) generation. We used output of a perturbed parameter ensemble (PPE) experiment conducted with an atmosphere–ocean general circulation model (AOGCM) without flux adjustment. The Model for Interdisciplinary Research on Climate version 5 (MIROC5) was used for the PPE experiment. Output of the PPE was compared with satellite observation data to evaluate the model biases and the parametric uncertainty of the biases with respect to TOA radiation and clouds. The results indicate that removing or changing the sign of the biases by parameter tuning alone is difficult. In particular, the cooling bias of the shortwave cloud radiative effect at low latitudes could not be removed, neither in the zonal mean nor at each latitude–longitude grid point. The bias was related to the overestimation of both cloud amount and cloud optical thickness, which could not be removed by the parameter tuning either. However, they could be alleviated by tuning parameters such as the maximum cumulus updraft velocity at the cloud base. On the other hand, the bias of the shortwave cloud radiative effect in the Arctic was sensitive to parameter tuning. It could be removed by tuning such parameters as albedo of ice and snow both in the zonal mean and at each grid point. The obtained results illustrate the benefit of PPE experiments which provide useful information regarding effectiveness and limitations of parameter tuning. Implementing a shallow convection parameterization is suggested as a potential measure to alleviate the biases in radiation and clouds. Article in Journal/Newspaper albedo Arctic Directory of Open Access Journals: DOAJ Articles Arctic Geoscientific Model Development 10 12 4647 4664 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Geology QE1-996.5 |
spellingShingle |
Geology QE1-996.5 T. Ogura H. Shiogama M. Watanabe M. Yoshimori T. Yokohata J. D. Annan J. C. Hargreaves N. Ushigami K. Hirota Y. Someya Y. Kamae H. Tatebe M. Kimoto Effectiveness and limitations of parameter tuning in reducing biases of top-of-atmosphere radiation and clouds in MIROC version 5 |
topic_facet |
Geology QE1-996.5 |
description |
This study discusses how much of the biases in top-of-atmosphere (TOA) radiation and clouds can be removed by parameter tuning in the present-day simulation of a climate model in the Coupled Model Inter-comparison Project phase 5 (CMIP5) generation. We used output of a perturbed parameter ensemble (PPE) experiment conducted with an atmosphere–ocean general circulation model (AOGCM) without flux adjustment. The Model for Interdisciplinary Research on Climate version 5 (MIROC5) was used for the PPE experiment. Output of the PPE was compared with satellite observation data to evaluate the model biases and the parametric uncertainty of the biases with respect to TOA radiation and clouds. The results indicate that removing or changing the sign of the biases by parameter tuning alone is difficult. In particular, the cooling bias of the shortwave cloud radiative effect at low latitudes could not be removed, neither in the zonal mean nor at each latitude–longitude grid point. The bias was related to the overestimation of both cloud amount and cloud optical thickness, which could not be removed by the parameter tuning either. However, they could be alleviated by tuning parameters such as the maximum cumulus updraft velocity at the cloud base. On the other hand, the bias of the shortwave cloud radiative effect in the Arctic was sensitive to parameter tuning. It could be removed by tuning such parameters as albedo of ice and snow both in the zonal mean and at each grid point. The obtained results illustrate the benefit of PPE experiments which provide useful information regarding effectiveness and limitations of parameter tuning. Implementing a shallow convection parameterization is suggested as a potential measure to alleviate the biases in radiation and clouds. |
format |
Article in Journal/Newspaper |
author |
T. Ogura H. Shiogama M. Watanabe M. Yoshimori T. Yokohata J. D. Annan J. C. Hargreaves N. Ushigami K. Hirota Y. Someya Y. Kamae H. Tatebe M. Kimoto |
author_facet |
T. Ogura H. Shiogama M. Watanabe M. Yoshimori T. Yokohata J. D. Annan J. C. Hargreaves N. Ushigami K. Hirota Y. Someya Y. Kamae H. Tatebe M. Kimoto |
author_sort |
T. Ogura |
title |
Effectiveness and limitations of parameter tuning in reducing biases of top-of-atmosphere radiation and clouds in MIROC version 5 |
title_short |
Effectiveness and limitations of parameter tuning in reducing biases of top-of-atmosphere radiation and clouds in MIROC version 5 |
title_full |
Effectiveness and limitations of parameter tuning in reducing biases of top-of-atmosphere radiation and clouds in MIROC version 5 |
title_fullStr |
Effectiveness and limitations of parameter tuning in reducing biases of top-of-atmosphere radiation and clouds in MIROC version 5 |
title_full_unstemmed |
Effectiveness and limitations of parameter tuning in reducing biases of top-of-atmosphere radiation and clouds in MIROC version 5 |
title_sort |
effectiveness and limitations of parameter tuning in reducing biases of top-of-atmosphere radiation and clouds in miroc version 5 |
publisher |
Copernicus Publications |
publishDate |
2017 |
url |
https://doi.org/10.5194/gmd-10-4647-2017 https://doaj.org/article/31fff4b4da5e461ca8794fd92c3dfa52 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
albedo Arctic |
genre_facet |
albedo Arctic |
op_source |
Geoscientific Model Development, Vol 10, Pp 4647-4664 (2017) |
op_relation |
https://www.geosci-model-dev.net/10/4647/2017/gmd-10-4647-2017.pdf https://doaj.org/toc/1991-959X https://doaj.org/toc/1991-9603 doi:10.5194/gmd-10-4647-2017 1991-959X 1991-9603 https://doaj.org/article/31fff4b4da5e461ca8794fd92c3dfa52 |
op_doi |
https://doi.org/10.5194/gmd-10-4647-2017 |
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Geoscientific Model Development |
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10 |
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12 |
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4647 |
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4664 |
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