(models of radiative transfer, often computerized)
A radiative transfer model (RTM) essentially defines and solves
a radiative transfer equation, which models how light passes through a material
(e.g., a not-fully-transparent gas) via radiative transfer.
Such modeling is done for meteorology as well as for astrophysics.
The equation relates a number of processes (absorption,
emission) which include non-linear aspects, and is not
partial to analytical solutions, generally requiring computation,
consisting of a code.