Atmospheric superrotation in an idealized GCM: Parameter dependence of the eddy response

Autor(es)

Dias Pinto, Joao Rafael ^{[1, 2]} ; Mitchell, Jonathan Lloyd ^{[2, 3]}

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Astron Geophys & Atmospher Sci, Dept Atmospher Sci, BR-05508090 Sao Paulo - Brazil

^[2] Univ Calif Los Angeles, Dept Earth Planetary & Space Sci, Los Angeles, CA 90095 - USA

^[3] Univ Calif Los Angeles, Dept Atmospher & Ocean Sci, Los Angeles, CA 90095 - USA

• Tipo de documento: Artigo Científico
• Fonte: ICARUS; v. 238, p. 93-109, AUG 2014.
• Citações Web of Science: 17

Resumo

Idealized Earth-like general circulation models (GCMs) have been extensively used to study superrotation on so-called ``slowly rotating{''} bodies like Venus and Titan, however they tend to have difficulty producing superrotation if only the rotation rate is reduced to Titan- or Venus-like values. The Rossby number, R-O = U/2 Omega L, which characterizes the influence of rotation on the circulation, is small for Earth but large for both Venus and Titan. However, the differences in other nondimensional control parameters are often ignored in idealized planetary circulation studies. In this study we use a simplified Earth-like GCM to demonstrate the importance of the other nondimensional parameters in obtaining a superrotating flow, and identify the wave-modes responsible for generating and maintaining superrotation. We show that superrotation only emerges on a planet of slow rotation rate if the atmospheric thermal inertia is simultaneously increased; alternatively, superrotation is obtained if the only planetary radius is reduced. When only the rotation rate is reduced, a nearly axisymmetric circulation with intense Hadley cells is produced that prevents strong and persistent winds over the equator. The mechanism for generating and maintaining superrotation in the model involves a coupling between equatorial and high-latitude waves. However, the generation involves equatorial Kelvin-like waves and maintenance involves equatorial Rossby-like waves. (C) 2014 Elsevier Inc. All rights reserved. (AU)

• Processo FAPESP: 10/15174-6 - Circulação geral e manutenção da superrotação da atmosfera de Titã
• Beneficiário: João Rafael Dias Pinto
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 12/13202-8 - Interação onda-escoamento médio e superrotação atmosférica em planetas terrestres
• Beneficiário: João Rafael Dias Pinto
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Doutorado