Item
Pujol i SagarÃ³, Toni
North, Gerald R. 

2002  
The effects of the nongray absorption (i.e., atmospheric opacity varying with wavelength) on the possible upper bound of the outgoing longwave radiation (OLR) emitted by a planetary atmosphere have been examined. This analysis is based on the semigray approach, which appears to be a reasonable compromise between the complexity of nongray models and the simplicity of the gray assumption (i.e., atmospheric absorption independent of wavelength). Atmospheric gases in semigray atmospheres make use of constant absorption coefficients in finitewidth spectral bands. Here, such a semigray absorption is introduced in a onedimensional (1D) radiativeâ€“ convective model with a stratosphere in radiative equilibrium and a troposphere fully saturated with water vapor, which is the semigray gas. A single atmospheric window in the infrared spectrum has been assumed. In contrast to the single absolute limit of OLR found in gray atmospheres, semigray ones may also show a relative limit. This means that both finite and infinite runaway effects may arise in some semigray cases. Of particular importance is the finding of an entirely new branch of stable steady states that does not appear in gray atmospheres. This new multiple equilibrium is a consequence of the nongray absorption only. It is suspected that this new set of stable solutions has not been previously revealed in analyses of radiativeâ€“convective models since it does not appear for an atmosphere with nongray parameters similar to those for the earthâ€™s current state  
application/pdf  
00224928 (versiÃ³ paper) 15200469 (versiÃ³ electrÃ²nica) 

http://hdl.handle.net/10256/7717  
eng  
American Meteorological Society  
ReproducciÃ³ digital del document publicat a: http://dx.doi.org/10.1175/15200469(2002)059<2801:RGEIAS>2.0.CO;2 Articles publicats (DF) 

Â© Journal of the Atmospheric Sciences, 2002, vol. 59, nÃºm. 19, p. 28012810  
Tots els drets reservats  
Efecte hivernacle (Meteorologia)
Greenhouse effect, Atmosphere RadiaciÃ³ atmosfÃ¨rica Atmospheric radiation Gasos  AbsorciÃ³ i adsorciÃ³ Gases  Absorption and adsorption 

Runaway Greenhouse Effect in a Semigray RadiativeConvective Model  
info:eurepo/semantics/article  
DUGiDocs 