A Linear Response Framework for Radiative-Convective Instability
Radiative-convective equilibrium is a simple paradigm for the tropical climate, in which radiative cooling balances convective heating in the absence of lateral energy transport. Recent studies have shown that a large-scale circulation may spontaneously develop from radiative-convective equilibrium...
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| Format: | Article |
| Language: | English |
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American Geophysical Union (AGU)
2020
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| Online Access: | https://hdl.handle.net/1721.1/125293 |
| _version_ | 1826204567701815296 |
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| author | Beucler, Tom G. Cronin, Timothy Wallace Emanuel, Kerry Andrew |
| 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 Beucler, Tom G. Cronin, Timothy Wallace Emanuel, Kerry Andrew |
| author_sort | Beucler, Tom G. |
| collection | MIT |
| description | Radiative-convective equilibrium is a simple paradigm for the tropical climate, in which radiative cooling balances convective heating in the absence of lateral energy transport. Recent studies have shown that a large-scale circulation may spontaneously develop from radiative-convective equilibrium through the interactions among water vapor, radiation, and convection. This potential instability, referred to as radiative-convective instability, may be posed as a linear stability problem for the water vapor profile by combining a linear response framework with the weak temperature gradient approximation. We design two analytic models of convective linear response to moisture perturbations, which are similar to Betts-Miller and bulk-plume convection schemes. We combine these convective responses with either clear-sky gray or real-gas radiative responses. In all cases, despite consistent radiative feedbacks, the characteristics of convection dominate the vertical structure of the most unstable linear mode of water vapor perturbations. For Betts-Miller convection, the stability critically depend on a key parameter: the heating to advection of moisture conversion rate (HAM); warmer atmospheres with higher HAM exhibit more linear instability. In contrast, bulk-plume convection is stable across temperatures but becomes linearly unstable with a moisture mode peaking in the midtroposphere once combined to radiation, with approximate growth rates of 10 days. |
| first_indexed | 2024-09-23T12:57:31Z |
| format | Article |
| id | mit-1721.1/125293 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T12:57:31Z |
| publishDate | 2020 |
| publisher | American Geophysical Union (AGU) |
| record_format | dspace |
| spelling | mit-1721.1/1252932022-10-01T12:10:17Z A Linear Response Framework for Radiative-Convective Instability Beucler, Tom G. Cronin, Timothy Wallace Emanuel, Kerry Andrew Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Radiative-convective equilibrium is a simple paradigm for the tropical climate, in which radiative cooling balances convective heating in the absence of lateral energy transport. Recent studies have shown that a large-scale circulation may spontaneously develop from radiative-convective equilibrium through the interactions among water vapor, radiation, and convection. This potential instability, referred to as radiative-convective instability, may be posed as a linear stability problem for the water vapor profile by combining a linear response framework with the weak temperature gradient approximation. We design two analytic models of convective linear response to moisture perturbations, which are similar to Betts-Miller and bulk-plume convection schemes. We combine these convective responses with either clear-sky gray or real-gas radiative responses. In all cases, despite consistent radiative feedbacks, the characteristics of convection dominate the vertical structure of the most unstable linear mode of water vapor perturbations. For Betts-Miller convection, the stability critically depend on a key parameter: the heating to advection of moisture conversion rate (HAM); warmer atmospheres with higher HAM exhibit more linear instability. In contrast, bulk-plume convection is stable across temperatures but becomes linearly unstable with a moisture mode peaking in the midtroposphere once combined to radiation, with approximate growth rates of 10 days. National Science Foundation (U.S.) (Grant AGS-1136480) National Science Foundation (U.S.) (Grant AGS-1418508) National Science Foundation (U.S.) (Grant AGS-1623218) 2020-05-18T19:42:20Z 2020-05-18T19:42:20Z 2018-08 2020-04-15T16:45:47Z Article http://purl.org/eprint/type/JournalArticle 1942-2466 https://hdl.handle.net/1721.1/125293 Beucler, Tom, Timothy Cronin and Kerry Emanuel. “A Linear Response Framework for Radiative-Convective Instability.” 10 (2018): 1924-1951 © 2018 The Author(s) en 10.1029/2018MS001280 Journal of Advances in Modelling Earth Systems Creative Commons Attribution-NonCommercial-NoDerivs License http://creativecommons.org/licenses/by-nc-nd/4.0/ application/pdf American Geophysical Union (AGU) American Geophysical Union (AGU) |
| spellingShingle | Beucler, Tom G. Cronin, Timothy Wallace Emanuel, Kerry Andrew A Linear Response Framework for Radiative-Convective Instability |
| title | A Linear Response Framework for Radiative-Convective Instability |
| title_full | A Linear Response Framework for Radiative-Convective Instability |
| title_fullStr | A Linear Response Framework for Radiative-Convective Instability |
| title_full_unstemmed | A Linear Response Framework for Radiative-Convective Instability |
| title_short | A Linear Response Framework for Radiative-Convective Instability |
| title_sort | linear response framework for radiative convective instability |
| url | https://hdl.handle.net/1721.1/125293 |
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