Clouds, Circulation, and Climate Sensitivity in a Radiative-Convective Equilibrium Channel Model
Tropical cloud and circulation changes are large sources of uncertainty in future climate change. This problem owes partly to the scale separation between large-scale tropical dynamics (~104km) and convective dynamics (~7 km), which generally requires parameterizing convection in models that resolve...
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| Format: | Article |
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American Geophysical Union (AGU)
2018
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| Online Access: | http://hdl.handle.net/1721.1/118160 https://orcid.org/0000-0002-7807-2878 https://orcid.org/0000-0003-2194-8709 |
| _version_ | 1826208999408664576 |
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| author | Cronin, Timothy Wallace Wing, Allison A. |
| author2 | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences |
| author_facet | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Cronin, Timothy Wallace Wing, Allison A. |
| author_sort | Cronin, Timothy Wallace |
| collection | MIT |
| description | Tropical cloud and circulation changes are large sources of uncertainty in future climate change. This problem owes partly to the scale separation between large-scale tropical dynamics (~104km) and convective dynamics (~7 km), which generally requires parameterizing convection in models that resolve large-scale dynamics, or parameterizing (or omitting) large-scale dynamics in models that permit convection. Here we discuss simulations of radiative-convective equilibrium (RCE) across a wide range of surface temperatures in long-channel geometry—where the domain size and resolution marginally resolve both large-scale dynamics and convection. Self-aggregation of convection in these simulations spontaneously produces realistic dynamical regimes of large-scale vertical motion. The circulation weakens with surface warming but changes in the degree of self-aggregation depend on the metric that is used; there is no obvious trend in aggregation with warming. Surface warming causes an upward shift and decrease in area of high clouds, and a sharp decline in midlevel clouds, but no systematic trend in low cloud cover. We introduce a method for approximate radiative kernel feedback analysis in RCE, and apply it to both simulations in long-channel geometry and in a smaller square domain. The kernel-corrected cloud feedback is positive but its magnitude varies across temperatures. Compared to simulations that do not have aggregation, there is a more negative net feedback due to the effects of aggregation on relative humidity and cloud cover. These results are consistent with the hypothesis that self-aggregation moderately reduces climate sensitivity. |
| first_indexed | 2024-09-23T14:15:46Z |
| format | Article |
| id | mit-1721.1/118160 |
| institution | Massachusetts Institute of Technology |
| last_indexed | 2024-09-23T14:15:46Z |
| publishDate | 2018 |
| publisher | American Geophysical Union (AGU) |
| record_format | dspace |
| spelling | mit-1721.1/1181602022-09-28T19:36:30Z Clouds, Circulation, and Climate Sensitivity in a Radiative-Convective Equilibrium Channel Model Cronin, Timothy Wallace Wing, Allison A. Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Cronin, Timothy Wallace Wing, Allison A. Tropical cloud and circulation changes are large sources of uncertainty in future climate change. This problem owes partly to the scale separation between large-scale tropical dynamics (~104km) and convective dynamics (~7 km), which generally requires parameterizing convection in models that resolve large-scale dynamics, or parameterizing (or omitting) large-scale dynamics in models that permit convection. Here we discuss simulations of radiative-convective equilibrium (RCE) across a wide range of surface temperatures in long-channel geometry—where the domain size and resolution marginally resolve both large-scale dynamics and convection. Self-aggregation of convection in these simulations spontaneously produces realistic dynamical regimes of large-scale vertical motion. The circulation weakens with surface warming but changes in the degree of self-aggregation depend on the metric that is used; there is no obvious trend in aggregation with warming. Surface warming causes an upward shift and decrease in area of high clouds, and a sharp decline in midlevel clouds, but no systematic trend in low cloud cover. We introduce a method for approximate radiative kernel feedback analysis in RCE, and apply it to both simulations in long-channel geometry and in a smaller square domain. The kernel-corrected cloud feedback is positive but its magnitude varies across temperatures. Compared to simulations that do not have aggregation, there is a more negative net feedback due to the effects of aggregation on relative humidity and cloud cover. These results are consistent with the hypothesis that self-aggregation moderately reduces climate sensitivity. National Science Foundation (U.S.) (Grant AGS-1623218) National Science Foundation (U.S.) (Grant AGS-1433251) 2018-09-21T15:36:21Z 2018-09-21T15:36:21Z 2017-12 2017-06 2018-09-20T17:56:53Z Article http://purl.org/eprint/type/JournalArticle 1942-2466 http://hdl.handle.net/1721.1/118160 Cronin, Timothy W., and Allison A. Wing. “Clouds, Circulation, and Climate Sensitivity in a Radiative-Convective Equilibrium Channel Model.” Journal of Advances in Modeling Earth Systems 9, 8 (December 2017): 2883–2905 © 2017 The Authors https://orcid.org/0000-0002-7807-2878 https://orcid.org/0000-0003-2194-8709 http://dx.doi.org/10.1002/2017MS001111 Journal of Advances in Modeling Earth Systems Creative Commons Attribution-NonCommercial-NoDerivs License http://creativecommons.org/licenses/by-nc-nd/4.0/ application/pdf American Geophysical Union (AGU) Wiley |
| spellingShingle | Cronin, Timothy Wallace Wing, Allison A. Clouds, Circulation, and Climate Sensitivity in a Radiative-Convective Equilibrium Channel Model |
| title | Clouds, Circulation, and Climate Sensitivity in a Radiative-Convective Equilibrium Channel Model |
| title_full | Clouds, Circulation, and Climate Sensitivity in a Radiative-Convective Equilibrium Channel Model |
| title_fullStr | Clouds, Circulation, and Climate Sensitivity in a Radiative-Convective Equilibrium Channel Model |
| title_full_unstemmed | Clouds, Circulation, and Climate Sensitivity in a Radiative-Convective Equilibrium Channel Model |
| title_short | Clouds, Circulation, and Climate Sensitivity in a Radiative-Convective Equilibrium Channel Model |
| title_sort | clouds circulation and climate sensitivity in a radiative convective equilibrium channel model |
| url | http://hdl.handle.net/1721.1/118160 https://orcid.org/0000-0002-7807-2878 https://orcid.org/0000-0003-2194-8709 |
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