The Juelich Rapid Spectral Simulation Code (JURASSIC) is a fast infrared radiative transfer model for the analysis of atmospheric remote sensing measurements. It combines efficient spectral approximations with precomputed lookup tables to model gaseous absorption, emission, and transmission in a form suitable for large simulation ensembles, retrieval studies, and operational workflows.

Overview

JURASSIC is designed to provide a practical balance between physical realism and computational efficiency. Typical applications include satellite radiance simulations, retrieval algorithm development, sensitivity studies, and campaign-style processing of atmospheric datasets.

The code base contains both forward-model components and retrieval functionality. The public declarations in jurassic.h provide a compact entry point to the core data structures and library interfaces used throughout the project.

Key capabilities

Fast infrared radiative transfer based on the Emissivity Growth Approximation (EGA) and Curtis-Godson Approximation (CGA).
Spectroscopic lookup tables derived from detailed line-by-line calculations.
Forward modelling for limb, nadir, and zenith observation geometries.
Optimal-estimation retrieval workflows for atmospheric state variables.
OpenMP and MPI support for large-scale and HPC-oriented use cases.

Documentation map

Different parts of the documentation serve different purposes:

The README.md gives a concise project introduction and installation overview.
The user manual covers theory, configuration, workflows, performance, and validation.
This Doxygen documentation focuses on the source-level API, algorithms, and internal data structures.

Recommended starting points in the user manual are:

References

For citing the model in scientific publications, please see CITATION.cff and refer to the following papers:

Baumeister, P. F. and Hoffmann, L.: Fast infrared radiative transfer calculations using graphics processing units: JURASSIC-GPU v2.0, Geosci. Model Dev., 15, 1855–1874, https://doi.org/10.5194/gmd-15-1855-2022, 2022.

Hoffmann, L., and M. J. Alexander, Retrieval of stratospheric temperatures from Atmospheric Infrared Sounder radiance measurements for gravity wave studies, J. Geophys. Res., 114, D07105, https://doi.org/10.1029/2008JD011241, 2009.

Hoffmann, L., Kaufmann, M., Spang, R., Müller, R., Remedios, J. J., Moore, D. P., Volk, C. M., von Clarmann, T., and Riese, M.: Envisat MIPAS measurements of CFC-11: retrieval, validation, and climatology, Atmos. Chem. Phys., 8, 3671-3688, https://doi.org/10.5194/acp-8-3671-2008, 2008.

Additional references are collected here: https://slcs-jsc.github.io/jurassic/references

License

JURASSIC is being developed at the Jülich Supercomputing Centre, Forschungszentrum Jülich, Germany.

JURASSIC is distributed under the terms of the GNU General Public License v3.0.

Contributing

Contributions that improve scientific robustness, documentation, portability, performance, and usability are welcome.

You can submit bug reports or feature requests on the issue tracker.

Proposed code changes and fixes can be submitted as pull requests.

Please do not hesitate to contact us if you have any questions or need assistance.

Contact

Dr. Lars Hoffmann

Jülich Supercomputing Centre, Forschungszentrum Jülich

e-mail: l.hof.nosp@m.fman.nosp@m.n@fz-.nosp@m.juel.nosp@m.ich.d.nosp@m.e