Features
========

Arts is a radiative transfer model. It is written in C++ and Python and
is available as open source under the GNU General Public License (GPL)
or the GNU Lesser General Public License (LGPL) via `GitHub <https://github.com/atmtools/arts>`_.

The model is able to simulate:

+ Passive and active microwave and sub-millimeter observations
+ Passive infrared observations
+ Passive visible and ultraviolet observations, including first order solar scattering
+ Observations from ground, airborne, and space-borne platforms
+ Observations of the Earth, other planets, and moon
+ Observations of the atmosphere, ocean, and land surface
+ Radiative flux and radiances in an atmosphere

The model supports:

+ Polarized radiative transfer
+ Spherical atmospheric geometry
+ Analytical Jacobians for many quantities
+ Retrieval of sensor parameters
+ Retrieval of surface parameters
+ Retrieval of atmospheric state parameters
+ Retrieval of line-by-line absorption parameters
+ Solving rotational non-lte level populations
+ Solving for the Zeeman effect in the presence of a magnetic field