A new, fast and flexible radiative transfer method for Venus general circulation models

• A description of a new, flexible and fast single-column radiative transfer model suitable for Venus GCM applications.
• The model includes representations of absorption and scattering due to gas, clouds and surface.
• The model does explicit calculations of the thermal and solar fluxes.
• The code allows one to easily change the atmospheric conditions or integration parameters.

We present a new radiation scheme for the Oxford Planetary Unified Model System for Venus, suitable for the solar and thermal bands. This new and fast radiative parameterization uses a different approach in the two main radiative wavelength bands: solar radiation (0.1–5.5μm) and thermal radiation (1.7–260μm). The solar radiation calculation is based on the δ-Eddington approximation (two-stream-type) with an adding layer method. For the thermal radiation case, a code based on an absorptivity/emissivity formulation is used.The new radiative transfer formulation implemented is intended to be computationally light, to allow its incorporation in 3D global circulation models, but still allowing for the calculation of the effect of atmospheric conditions on radiative fluxes. This will allow us to investigate the dynamical-radiative-microphysical feedbacks. The model flexibility can be also used to explore the uncertainties in the Venus atmosphere such as the optical properties in the deep atmosphere or cloud amount.The results of radiative cooling and heating rates and the global-mean radiative–convective equilibrium temperature profiles for different atmospheric conditions are presented and discussed. This new scheme works in an atmospheric column and can be easily implemented in 3D Venus global circulation models.