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States of maximum entropy production in a onedimensional vertical model with convective adjustment

We investigate the hypothesis that the atmosphere is constrained to maximize its entropy production by using a one-dimensional (1-D) vertical model. We prescribe the lapse rate in the convective layer as that of the standard troposphere. The assumption that convection sustains a critical lapse rate was absent in previous studies, which focused on the vertical distribution of climatic variables, since such a convective adjustment reduces the degrees of freedom of the system and may prevent the application of the maximum entropy production (MEP) principle. This is not the case in the radiative–convective model (RCM) developed here, since we accept a discontinuity of temperatures at the surface similar to that adopted in many RCMs. For current conditions, the MEP state gives a difference between the ground temperature and the air temperature at the surface ≈10 K. In comparison, conventional RCMs obtain a discontinuity ≈2 K only. However, the surface boundary layer velocity in the MEP state appears reasonable (≈3 m s-¹). Moreover, although the convective flux at the surface in MEP states is almost uniform in optically thick atmospheres, it reaches a maximum value for an optical thickness similar to current conditions. This additional result may support the maximum convection hypothesis suggested by Paltridge (1978)

© Tellus Series A-Dynamic Meteorology and Oceanography, 2002, vol. 54, núm. 4, p. 363-369

International Meteorological Institute in Stockholm

Author: Pujol i Sagaró, Toni
Fort, Joaquim
Date: 2002
Abstract: We investigate the hypothesis that the atmosphere is constrained to maximize its entropy production by using a one-dimensional (1-D) vertical model. We prescribe the lapse rate in the convective layer as that of the standard troposphere. The assumption that convection sustains a critical lapse rate was absent in previous studies, which focused on the vertical distribution of climatic variables, since such a convective adjustment reduces the degrees of freedom of the system and may prevent the application of the maximum entropy production (MEP) principle. This is not the case in the radiative–convective model (RCM) developed here, since we accept a discontinuity of temperatures at the surface similar to that adopted in many RCMs. For current conditions, the MEP state gives a difference between the ground temperature and the air temperature at the surface ≈10 K. In comparison, conventional RCMs obtain a discontinuity ≈2 K only. However, the surface boundary layer velocity in the MEP state appears reasonable (≈3 m s-¹). Moreover, although the convective flux at the surface in MEP states is almost uniform in optically thick atmospheres, it reaches a maximum value for an optical thickness similar to current conditions. This additional result may support the maximum convection hypothesis suggested by Paltridge (1978)
Format: application/pdf
ISSN: 1600-0870 (versió electrònica)
0280-6495 (versió paper)
Document access: http://hdl.handle.net/10256/7718
Language: eng
Publisher: International Meteorological Institute in Stockholm
Collection: Reproducció digital del document publicat a: http://dx.doi.org/10.1034/j.1600-0870.2002.01382.x
Articles publicats (D-F)
Is part of: © Tellus Series A-Dynamic Meteorology and Oceanography, 2002, vol. 54, núm. 4, p. 363-369
Rights: Attribution-NonCommercial 3.0 Spain
Rights URI: http://creativecommons.org/licenses/by-nc/3.0/es/
Subject: Radiació atmosfèrica
Atmospheric radiation
Entropia
Entropy
Termodinàmica
Thermodynamic
Title: States of maximum entropy production in a onedimensional vertical model with convective adjustment
Type: info:eu-repo/semantics/article
Repository: DUGiDocs

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