3D simulations of the Archean Earth including photochemical haze profiles

Abstract

We present results from 3D simulations of the Archean Earth including a prescribed (non-interactive) spherical haze generated through a 1D photochemical model. Our sim ulations suggest that a thin haze layer, formed when CH4/CO2 = 0.1, leads to global warming of ∼10.6K due to the change of water vapour and cloud feedback, compared to the simulation without any haze. However, a thicker haze layer, formed when CH4/CO2 > 0.1, leads to global cooling of up to ∼65K as the scattering and absorption of short wave radiation from the haze reduces the radiation from reaching the planetary surface. A thermal inversion is formed with a lower tropopause as the CH4/CO2 ratio increases. The haze reaches an optical threshold thickness when CH4/CO2 ∼ 0.175 beyond which the atmospheric structure and the global surface temperature do not vary much.