A Refined Understanding of the Ice Cloud Longwave Scattering Effects in Climate Model
Abstract Because longwave (LW) absorption by greenhouse gases and clouds is more significant than the LW scattering effect by clouds, most climate models neglect cloud LW scattering to save computational costs. Ignoring cloud LW scattering directly overestimates outgoing longwave radiation (OLR). Th...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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American Geophysical Union (AGU)
2023-10-01
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| Series: | Journal of Advances in Modeling Earth Systems |
| Subjects: | |
| Online Access: | https://doi.org/10.1029/2023MS003810 |
| _version_ | 1797635993026691072 |
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| author | Chongxing Fan Yi‐Hsuan Chen Xiuhong Chen Wuyin Lin Ping Yang Xianglei Huang |
| author_facet | Chongxing Fan Yi‐Hsuan Chen Xiuhong Chen Wuyin Lin Ping Yang Xianglei Huang |
| author_sort | Chongxing Fan |
| collection | DOAJ |
| description | Abstract Because longwave (LW) absorption by greenhouse gases and clouds is more significant than the LW scattering effect by clouds, most climate models neglect cloud LW scattering to save computational costs. Ignoring cloud LW scattering directly overestimates outgoing longwave radiation (OLR). This study included ice‐cloud LW scattering treatment in the Exascale Energy Earth System Model (E3SM) version 2 and ran fully‐coupled simulations, prescribed sea surface temperature simulations, and offline radiative transfer calculations to comprehensively assess the impact of ice‐cloud LW scattering on global climate simulation. The instantaneous effect due to ice‐cloud LW scattering reduces the OLR by ∼1 W/m2 on the global average and 2 W/m2 on the tropical average. Tropospheric warming and high cloud amount reduction act to partially compensate for such instantaneous OLR reduction caused by the inclusion of LW scattering. When the simulation reaches the equilibrium, the surface warms by 0.66 K on average with respect to the simulation without LW scattering, with the Arctic surface temperature differences more than twice as large as that of the global mean. The impact of including LW scattering on the simulated climate change in response to 4 × CO2 is also assessed. While including the cloud LW scattering does not significantly modify radiative forcing and total radiative feedback under such a scenario, it results in a 10% more positive cloud feedback. |
| first_indexed | 2024-03-11T12:27:47Z |
| format | Article |
| id | doaj.art-bfd2d856bd9d486e848349977332140f |
| institution | Directory Open Access Journal |
| issn | 1942-2466 |
| language | English |
| last_indexed | 2024-03-11T12:27:47Z |
| publishDate | 2023-10-01 |
| publisher | American Geophysical Union (AGU) |
| record_format | Article |
| series | Journal of Advances in Modeling Earth Systems |
| spelling | doaj.art-bfd2d856bd9d486e848349977332140f2023-11-06T06:42:17ZengAmerican Geophysical Union (AGU)Journal of Advances in Modeling Earth Systems1942-24662023-10-011510n/an/a10.1029/2023MS003810A Refined Understanding of the Ice Cloud Longwave Scattering Effects in Climate ModelChongxing Fan0Yi‐Hsuan Chen1Xiuhong Chen2Wuyin Lin3Ping Yang4Xianglei Huang5Department of Climate and Space Sciences and Engineering the University of Michigan Ann Arbor MI USADepartment of Climate and Space Sciences and Engineering the University of Michigan Ann Arbor MI USADepartment of Climate and Space Sciences and Engineering the University of Michigan Ann Arbor MI USAEnvironmental & Climate Sciences Department Brookhaven National Laboratory New York State NY USADepartment of Atmospheric Sciences Texas A&M University College Station TX USADepartment of Climate and Space Sciences and Engineering the University of Michigan Ann Arbor MI USAAbstract Because longwave (LW) absorption by greenhouse gases and clouds is more significant than the LW scattering effect by clouds, most climate models neglect cloud LW scattering to save computational costs. Ignoring cloud LW scattering directly overestimates outgoing longwave radiation (OLR). This study included ice‐cloud LW scattering treatment in the Exascale Energy Earth System Model (E3SM) version 2 and ran fully‐coupled simulations, prescribed sea surface temperature simulations, and offline radiative transfer calculations to comprehensively assess the impact of ice‐cloud LW scattering on global climate simulation. The instantaneous effect due to ice‐cloud LW scattering reduces the OLR by ∼1 W/m2 on the global average and 2 W/m2 on the tropical average. Tropospheric warming and high cloud amount reduction act to partially compensate for such instantaneous OLR reduction caused by the inclusion of LW scattering. When the simulation reaches the equilibrium, the surface warms by 0.66 K on average with respect to the simulation without LW scattering, with the Arctic surface temperature differences more than twice as large as that of the global mean. The impact of including LW scattering on the simulated climate change in response to 4 × CO2 is also assessed. While including the cloud LW scattering does not significantly modify radiative forcing and total radiative feedback under such a scenario, it results in a 10% more positive cloud feedback.https://doi.org/10.1029/2023MS003810cloud longwave scatteringcloud‐radiation interactionradiative forcing and feedbackE3SMclimate modeling |
| spellingShingle | Chongxing Fan Yi‐Hsuan Chen Xiuhong Chen Wuyin Lin Ping Yang Xianglei Huang A Refined Understanding of the Ice Cloud Longwave Scattering Effects in Climate Model Journal of Advances in Modeling Earth Systems cloud longwave scattering cloud‐radiation interaction radiative forcing and feedback E3SM climate modeling |
| title | A Refined Understanding of the Ice Cloud Longwave Scattering Effects in Climate Model |
| title_full | A Refined Understanding of the Ice Cloud Longwave Scattering Effects in Climate Model |
| title_fullStr | A Refined Understanding of the Ice Cloud Longwave Scattering Effects in Climate Model |
| title_full_unstemmed | A Refined Understanding of the Ice Cloud Longwave Scattering Effects in Climate Model |
| title_short | A Refined Understanding of the Ice Cloud Longwave Scattering Effects in Climate Model |
| title_sort | refined understanding of the ice cloud longwave scattering effects in climate model |
| topic | cloud longwave scattering cloud‐radiation interaction radiative forcing and feedback E3SM climate modeling |
| url | https://doi.org/10.1029/2023MS003810 |
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