Robust elements of Snowball Earth atmospheric circulation and oases for life

D. S. Abbot, A. Voigt, D. Li, G. L. Hir, R. T. Pierrehumbert, M. Branson, D. Pollard, and D. D. B. Koll

Journal of Geophysical Research, D: Atmospheres (27 June 2013)

DOI: 10.1002/jgrd.50540

Atmospheric circulation in a Snowball Earth is critical for determining cloud behavior, heat export from the tropics, regions of bare ice, and sea glacier flow. These processes strongly affect Snowball Earth deglaciation and the ability of oases to support photosynthetic marine life throughout a Snowball Earth. Here we establish robust aspects of the Snowball Earth atmospheric circulation by running six general circulation models with consistent Snowball Earth boundary conditions. The models produce qualitatively similar patterns of atmospheric circulation and precipitation minus evaporation. The strength of the Snowball Hadley circulation is roughly double modern at low CO2 and greatly increases as CO2 is increased. We force a 1‒D axisymmetric sea glacier model with general circulation model (GCM) output and show that, neglecting zonal asymmetry, sea glaciers would limit ice thickness variations to O(10

keywords: snowball earth; hadley cell; neoproterozoic; astrobiology; 3319 General circulation; 3337 Global climate models; 3344 Paleoclimatology; 3373 Tropical dynamics; 9622 Proterozoic

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