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Jülich Rapid Spectral Simulation Code

Scientific area

Fast solver for infrared radiative transfer in the Earth's atmosphere.

Short description

JURASSIC is a fast radiative transfer model for the infrared spectral region in the Earth's atmosphere. The model solves the Schwarzschild Equation for the transmission of radiation by means of fast and accurate approximations (CGA and EGA) and pre-calculated look-up tables for spectral mean emissivity.

JURASSIC found many applications in the analysis of remote sensing observations from satellite instruments, including NASA's Atmospheric Infrared Sounder (AIRS) and ESA's Michelson Interferometer for Passive Atmospheric Sounding (MIPAS). JURASSIC was also used to retrieve atmospheric data from aircraft instruments, to solve tomographic inversion problems, and to study scattering of Infrared radiation at atmospheric aerosol and cloud particles.

The model was developed at the Institute of Energy and Climate Research and at the Jülich Supercomputing Centre, both at the Research Centre Jülich.

AIRSEarth-observing satellite instruments such as NASA's AIRS provide tens to hundreds of TByte of measurement data during their lifetime. JURASSIC is used to retrieve atmospheric data from the satellite's radiance measurements.


  • 458,752 cores (1,835,008 compute threads) on BlueGene/Q (JUQUEEN)

Weak scaling of JURASSIC on JUQUEENWeak scaling test of an AIRS retrieval with JURASSIC on JUQUEEN. The test indicates limited parallel efficiency for I/O and communication. However, the total run-time of the problem is dominated by computation - with excellent efficiency (100%) up to one million threads and very good efficiency (85%) on the full machine.

Programming language and model

  • C
  • MPI, OpenMP

Tested on platforms

  • BlueGene/Q
  • x86


Lars Hoffmann
Jülich Supercomputing Centre
Forschungszentrum Jülich GmbH
52425 Jülich

(Text and images provided by the developers)