A Linear Response Framework for Radiative-Convective Instability
Name
2018MS001280.pdf
Description
Published version
Size
2.88 MB
Format
Adobe PDF
Checksum (MD5)
02b7d0a68b0cfd70c2306162bdd39c49
Author(s)
Beucler, Tom G.
Cronin, Timothy Wallace
Emanuel, Kerry Andrew
Date Issued
August 2018
Journal
Journal of Advances in Modelling Earth Systems
Publisher
American Geophysical Union (AGU)
Citation
Beucler, Tom, Timothy Cronin and Kerry Emanuel. “A Linear Response Framework for Radiative-Convective Instability.” 10 (2018): 1924-1951 © 2018 The Author(s)
Version
Final published version
Abstract
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.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Terms of Use
Creative Commons Attribution-NonCommercial-NoDerivs License
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1029/2018MS001280
