Introduction

PlanarRad is free software for modelling light in natural waters or other homegenous scattering and absorbing media. It is functionally similar to the commercial software HydroLight.

PlanarRad does not have:

  • Infinite depth water

  • Vertical stratification of optical parameters

  • Inelastic scattering (chlorophyll or CDOM fluoresence, Raman scattering)

  • Any bio-optical models, you must provide IOPs directly rather than chlorophyll concentration. However PlanarRadBatch provides functions for this.

However PlanarRad does have:

  • An attractive price point - it’s free as in beer

  • Open source code licensed under the GPL - it’s free as in freedom

  • Highly scriptable command-line interface

  • Output results in an easily manageable text file

  • GUI front-end with interactive visualisations and plots (ideal for educational use)

  • Automatic spectral resampling for easy integration of data from multiple instruments

  • Ability to load in actual irradiance or radiance profiles for comparison to model outputs - i.e. model closure experiments

  • Easy reconfiguration of the directional discretization of radiance - no recompiling required

  • Nearly identical results to HydroLight that can be verified on your own machine - example report

  • A user-generated user manual. You are reading it! Please contribute!

More Information

PlanarRad is a freely available open-source C++ implementation of the invariant imbedded numerical integration technique for calculating radiative transfer in plane-parallel media with an opaque bottom boundary. It is based on the algorithm described in Curt Mobley’s book Light and Water, and was designed for modelling light propagation in, and reflection from, shallow water environments. However, by setting a suitably large depth an infinite depth solution can be approximated. PlanarRad was originally developed by John Hedley during a period in which he was based at the University of Exeter and variously funded by Natural Environment Research Council and the World Bank / GEF Coral Reef Targeted Research Project. The NERC Field Spectroscopy Facility also indirectly supported PlanarRad by funding the development of the WLTool software.

Old versions of PlanarRad can be found on the previous versions page.

There are also some other community maintained versions that may be more up to date than v0.9.5 linked above:

  • marrabld’s has a version containing a python-GUI for batch scripting

Citing PlanarRad

If you make use of PlanarRad in a publication the most suitable peer-review publication to cite is:

Hedley, J (2008). A three-dimensional radiative transfer model for shallow water environments, Optics Express 16, 21887-21902.

The main topic of that paper is a different radiative transfer model, but PlanarRad was also used and Figure 5 of that paper can be considered a validation of PlanarRad by model intercomparison.

See here for the Full list of publications using PlanarRad.

If you publish anything using PlanarRad, we would love to know, please do so by making a post on the github.

Support and bug reports

PlanarRad is unfunded so my ability to provide support is extremely limited. Nevertheless the authors are likely to respond to an email/dm/post. If you would like to help PlanarRad survive, please report any bugs you find and/or make feature requests and/or get in touch!