Gastropod

Introduction

Gastropod is an Open Source Free Software Fortran 90 library of forward and gradient routines for fast radiative transfer calculations for the advanced infrared sounders. The source code is available free of charge under the Free Software LGPL license.

Gastropod was initially developed at The Met Office (UK). Ongoing development is supported by NIWA (New Zealand's National Institute of Water and Atmospheric Research).

The current distribution (version 0.3.0) comprises:

• Forward and gradient (tangent linear, adjoint and Jacobian) routines for radiative transfer in a plane parallel atmosphere of non-scattering gaseous absorbers in local thermodynamic equilibrium, with specular reflection at the Earth's surface.
• A validated gaseous absorption regression model for the Atmospheric Infrared Sounder, AIRS.
• AIRS fast radiative transfer model wrapper codes with a flexible input interface enabling:
  • runtime specification of input profile units (mass and volume mixing ratios with respect to total and dry air) and the AIRS ISRF,
  • profile input and Jacobian output on user-defined pressure levels,
  • radiative transfer calculations for user-specified channel subsets.
• Code to interface Gastropod with the Met Office 1D-Var (v3) retrieval software distributed by the Eumetsat NWP SAF.

Future developments include:

• a prognostic infrared surface emissivity model,
• a model of downwelling solar radiation,
• a model of scattering and absorption in cloud.

If you intend to use (and/or contribute) to the Gastropod project, or have any technical questions concerning Gastropod, please post to the gastro-users mailing list.

Obtaining Gastropod

Releases

• Download Gastropod Version 0.3.0 (latest release, April 2005)
• Download Gastropod Version 0.2.0 (August 2002 release)

Regression coefficients

• Download AIRS regression coefficients.

Code development under CVS

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Documentation

Installation information

Related References

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