The JUelich RApid Spectral SImulation Code with scattering is based on JURASSIC (https://github.com/slcs-jsc/jurassic), but was a bit reorganized to include modules that allow simulations with scattering on aerosol and cloud particles.
The Juelich Rapid Spectral Simulation Code (JURASSIC) is a fast radiative transfer model for the mid-infrared spectral region (Hoffmann, 2006). It was used in several studies for the infrared limb sounder Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) (Hoffmann et al., 2005, 2008), Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere - New Frontiers (CRISTA-NF) (Hoffmann et al., 2009; Weigel et al., 2010), and Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) (Ungermann et al., 2010) and the nadir instrument Atmospheric Infrared Sounder (AIRS) (Hoffmann and Alexander, 2009; Grimsdell et al., 2010; Hoffmann et al., 2013).
For fast simulations, it applies pre-calculated look-up tables of spectral emissivities and approximations to radiative transfer calculations, such as the emissivity growth approximation (EGA) (Weinreb and Neuendorffer, 1973; Gordley and Russell, 1981; Marshall et al., 1994).The look-up-tables were calculated with the Reference Forward Model (RFM) (Dudhia et al., 2002; Dudhia, 2014), which is an exact line-by-line model specifically developed for MIPAS. For selected spectral windows, JURASSIC-scatter has been compared to the line-by-line models RFM and Karlsruhe Optimized and Precise Radiative transfer Algorithm (KOPRA) (Stiller, 2000; Stiller et al., 2002; Höpfner and Emde, 2005) and shows good agreement (Griessbach et al., 2013).
JURASSIC-scatter contains a scattering module that allows for radiative transfer simulations including single scattering on aerosol and cloud particles (Grießbach, 2012; Griessbach et al., 2013). Forward simulations with scattering on volcanic ash, ice and sulfate aerosol have been used to develop and characterise a volcanic ash detection method for MIPAS (Griessbach et al., 2012, 2014).
Retrieval of large satellite data sets require plenty of computing time that can be provided by supercomputers. JURASSIC-scatter shows best performance using a hybrid MPI/openMP parallelization on JURECA and JUWELS at the Jülich Supercomputing Centre (JSC), Forschungszentrum Jülich GmbH. It can also be used on workstations or laptops using pure MPI or openMP parallelization.
In the documentation you will find a quick start, examples of how to run simulations, a description of the input and output file formats, a list of control flags and their options, as well as examples of how to use the modules. The documentation is neither ready nor perfect, but it is a start to introduce you to JURASSIC-scatter and to enable you to work and to do science with this code package.
We are interested in sharing JURASSIC-scatter for operational or research applications.
Please do not hesitate to contact us, if you have any further questions or need support.
JURASSIC-scatter is distributed under the GNU GPL v3.
Dr. Sabine Grießbach
Dr. Lars Hoffmann
Jülich Supercomputing Centre, Forschungszentrum Jülich