Karlsruhe optimized and precise radiative transfer algorithm: Part III: ADDLIN and TRANSF algorithms for modeling spectral transmittance and radiance

Abstract

Two sets of subroutines for calculating absorption cross section spectra and transmission or radiance fields are presented. These libraries will be used in the operational data processing of the MIPAS/ENVISAT level-2 off-line processor and are part of the Karisruhe Optimized and Precise Radiative transfer Algorithm (KOPRA). The objective in developing these libraries was to accommodate flexibility and simplicity in use without substantial loss of accuracy and efficiency.The ADDLTN library uses an efficient method for calculating absorption cross section spectra line-by-line to arbitrary high numerical accuracy. Computational efficiency is achieved by calculating each spectral line on its own optimum set of sampling points. Absorption cross section spectra are stored on flexible, non-equidistant frequency grids.The TRANSF package provides integration routines that can be quickly configured for a variety of specific applications and measurement scenarios. The routines operate on the non-equidistant frequency grids produced by ADDINand allow the researcher to implement the radiative transfer in a simple and almost natural way. Computational efficiency results from the reduced number of sampling points on the non-equidistant frequency grids compared to equidistant frequency grids of uniform intervals.

Long‐term trends of inorganic chlorine from ground‐based infrared solar spectra: Past increases and evidence for stabilization

“…This code is similar to SFIT2, but retrieves profiles on a logarithmic volume mixing ratio scale. The radiative transfer code used is KOPRA Kuntz et al, 1998;Stiller et al, 1998]. NCEP temperature profiles, smoothly merged with the CIRA86 climatology (http://badc.rl.ac.uk/data/cira) above 45 km, were used for the analysis.…”

Quality assessment of O<sub>3</sub> profiles measured by a state-of-the-art ground-based FTIR observing system

“…We use the retrieval code PROFFIT 9.4 (Hase et al, 2004) with the option to retrieve isotopologue ratio profiles (Schneider et al, 2006b). It applies the Karlsruhe Optimised and Precise Radiative Transfer Algorithm (KOPRA, Höpfner et al, 1998;Kuntz et al, 1998;Stiller et al, 1998) as the forward model, which was developed for the analysis of MIPAS-Envisat limb sounder spectra. For the atmospheric O 3 retrieval we analyse a combination of small and broad spectral windows between 780-1015 cm −1 .…”

Comparison of ground-based Brewer and FTIR total column O<sub>3</sub> monitoring techniques

“…The FTIR retrieval (PROFFIT, Hase et al, 2004) applies a precise radiative transfer model (KOPRA, Höpfner et al, 1998;Kuntz et al, 1998;Stiller et al, 1998). KOPRA is a line-by-line model which simulates the measured spectra.…”