3D radiative-transfer for exoplanet atmospheres. gCMCRT: a GPU accelerated MCRT code
Elspeth K.H. Lee, Joost P. Wardenier, Bibiana Prinoth, Vivien Parmentier, Simon L. Grimm, Robin Baeyens, Ludmila Carone, Duncan Christie, Russell Deitrick, Daniel Kitzmann, Nathan Mayne, Michael Roman
Radiative-transfer (RT) is a key component for investigating atmospheres of
planetary bodies. With the 3D nature of exoplanet atmospheres being important
in giving rise to their observable properties, accurate and fast 3D methods are
required to be developed to meet future multi-dimensional and temporal data
sets. We develop an open source GPU RT code, gCMCRT, a Monte Carlo RT forward
model for general use in planetary atmosphere RT problems. We aim to automate
the post-processing pipeline, starting from direct global circulation model
(GCM) output to synthetic spectra. We develop albedo, emission and transmission
spectra modes for 3D and 1D input structures. We include capability to use
correlated-k and high-resolution opacity tables, the latter of which can be
Doppler shifted inside the model. We post-process results from several GCM
groups including ExoRad, SPARC/MITgcm THOR, UK Met Office UM, Exo-FMS and the
Rauscher model. Users can therefore take advantage of desktop and HPC GPU
computing solutions. gCMCRT is well suited for post-processing large GCM model
grids produced by members of the community and for high-resolution 3D
investigations.