GARLIC — A Generic Atmospheric Radiation Line-by-line Infrared Code for Earth and Planetary Science

Abstract

GARLIC has been developed with emphasis on efficient and reliable numerical algorithms and a modular approach appropriate for simulation and/or retrieval in a variety of applications. It is suitable for arbitrary observation geometry, instrumental field-of-view, and line shape. The core of GARLIC's subroutines constitutes the basis of forward models used to implement inversion codes to retrieve atmospheric state parameters from limb and nadir sounding instruments. In view of the computational burden of lbl modeling considerable effort has been devoted to optimized algorithms. Collision induced absorption has been implemented as a complement of the H2O, CO2, etc continua. Furthermore, the DISORT multiple-scattering solver has been added to GARLIC for an assessment of the impact of clouds on exoplanet spectra. As a recent upgrade Jacobians with respect to temperature have been implemented utilizing algorithmic differentiation. In this contribution we summarize GARLIC's main features and give some examples from Earth and planetary science.