CIDGA - Coupling of Interior Dynamic Models with Global Atmosphere Models

Abstract

Climate models and surface temperatures mostly depend on the solar heat flux and the composition of the atmosphere. The latter can be influenced by interior processes of the planet like volcanism, that releases greenhouse gases such as H2O and CO2 into the atmosphere, and plate tectonics, that recycles the atmospheric CO2 into the mantle. A higher concentration of greenhouse gases in the atmosphere results in a higher surface temperature, which might influence the convection pattern in the mantle of the planet and hence influence surface processes. This feedback relation between mantle convection and atmosphere is still not very well understood, since until now mostly either the interior of a planet or its atmosphere was investigated. 2D or 3D mantle convection models to the author's knowledge haven't been coupled to the atmosphere so far. The 3D spherical simulation code GAIA developed by the Joint Planetary Interior Physics Research Group of the University Münster and IfP DLR Berlin has been extended by the atmosphere module CIDGA using a gray greenhouse model. Investigating the thermal evolution of Venus, it has been shown that an increase of surface temperature leads not only to an increase of partial melt in the mantle, but also to a strong decrease of lid thickness and hence its isolating effect. The mantle temperatures and with this the amount of partial melt decrease much faster than when the change in surface temperature has not been considered for the mantle convection.