ARTS, the atmospheric radiative transfer simulator, version 2

Abstract

The second version of the atmospheric radiative transfer simulator, ARTS, is introduced. This is a general software package for long wavelength radiative transfer simulations, with a focus on passive microwave observations. The core part provides a workspace environment, in line with script languages. New for this version is an agenda mechanism that gives a high degree of modularity. The framework is intended to be as general as possible: the polarisation state can be fully described, the model atmosphere can be one-(1D), two-(2D) or three-dimensional (3D), a full description of geoid and surface is possible, observation geometries from the ground, from satellite, and from aeroplane or balloon are handled, and surface reflection can be treated in simple or complex manners. Remote sensing applications are supported by a comprehensive and efficient treatment of sensor characteristics. Jacobians can be calculated for the most important atmospheric variables in non-scattering conditions. Finally, the most prominent feature is the rigorous treatment of scattering that has been implemented in two modules: a discrete ordinate iterative approach mainly used for 1D atmospheres, and a Monte Carlo approach which is the preferred algorithm for 3D atmospheres. ARTS is freely available, and maintained as an open-source project.

Simulation study for measurement of horizontal wind profiles in the polar stratosphere and mesosphere using ground-based observations of ozone and carbon monoxide lines in the 230–250 GHz region

“…The Atmospheric Radiative Transfer Simulator (ARTS) (version 2.2.0) available at http://www.radiativetransfer.org/ is the forward model used in this study Eriksson et al, 2011). ARTS is a line-by-line model that can simulate radiances from the infrared to the microwave, and has been validated against other models in the millimetre spectral range (Melsheimer et al, 2005).…”

ARTS, the Atmospheric Radiative Transfer Simulator – version 2.2, the planetary toolbox edition

“…Besides this extension, there were numerous improvements and developments compared to the last version that is described in the literature (Eriksson et al, 2011a), and the most important of these are also described.…”

“…Earlier ARTS versions (Buehler et al, 2005a;Eriksson et al, 2011a) follow the common approach of standard air foreign broadening and pressure shift parameters, calculating the pressure-broadened line width γ L as…”

“…The line-byline absorption calculation itself, however, does also work in the solar spectral range and has been used by Gasteiger et al (2014) to pre-calculate absorption cross sections for li- Absorption vector, extinction matrix, and discrete angular grid four-by-four phase matrix (have to be externally generated) Jacobian calculation Analytical and/or semi-analytical for clear-sky variables; no Jacobians in the presence of scattering in the version described in this article, but this feature is under development bRadtran (Emde et al, 2016), using the simulated annealing method described in Buehler et al (2010). There are only two previous publications that describe earlier versions of ARTS as a whole (Buehler et al, 2005a andEriksson et al, 2011a), but many of the main building blocks of ARTS and the tools around it have been described in dedicated publications. Besides the already mentioned DOIT and MC scattering solvers, important building blocks are the method to pre-calculate and store gas absorption data and the method to handle sensor characteristics by building up a comprehensive sparse matrix sensor representation .…”

Tomographic retrieval of water vapour and temperature around polar mesospheric clouds using Odin-SMR

“…It is publicly available software. The second version of ARTS (Eriksson et al, 2011) allows simulations for 1-D, 2-D or 3-D atmospheres, where the 2-D option is applied in this study. ARTS uses pressure as the main vertical coordinate.…”