Impact of variations of gravitational acceleration on the general circulation of the planetary atmosphere. (January 2017)

• Record Type: Journal Article
• Authors: Kilic, Cevahir; Raible, Christoph C.; Stocker, Thomas F.; Kirk, Edilbert
• Is Part Of: Planetary and space science. Volume 135(2016)
• Page Start: 1
• Page End: 16
• Publication Date: 2017-01
• Subjects: Planetary atmospheres -- General atmospheric circulation -- Global energy cycle -- Gravitational acceleration -- Atmospheric simulation; Space sciences -- Periodicals; Atmosphere, Upper -- Periodicals; Sciences spatiales -- Périodiques; Haute atmosphère -- Périodiques; 523
• DOI: 10.1016/j.pss.2016.11.001
• Languages: English
• ISSNs: 0032-0633

Abstract

Abstract: Fundamental to the redistribution of energy in a planetary atmosphere is the general circulation and its meridional structure. We use a general circulation model of the atmosphere in an aquaplanet configuration with prescribed sea surface temperature and investigate the influence of the gravitational acceleration g on the structure of the circulation. For g = g 0 = 9.81 m s − 2, three meridional cells exist in each hemisphere. Up to about g / g 0 = 1.4 all cells increase in strength. Further increasing this ratio results in a weakening of the thermally indirect cell, such that a two- and finally a one-cell structure of the meridional circulation develops in each hemisphere. This transition is explained by the primary driver of the thermally direct Hadley cell: the diabatic heating at the equator which is proportional to g . The analysis of the energetics of the atmospheric circulation based on the Lorenz energy cycle supports this finding. For Earth-like gravitational accelerations transient eddies are primarily responsible for the meridional heat flux. For large gravitational accelerations, the direct zonal mean conversion of energy dominates the meridional heat flux. Abstract : Highlights: The planet's gravity determines the meridional structure of atmospheric circulation. An energy cycle analysis reveals the major drivers of the atmospheric circulation. With increasing gravity the meridional circulation changes from 3 cells to 1 cell.