Page History

Introduction

This page describes how to access the offline version of the new ECMWF radiation scheme "ecRad", which is operational in the ECMWF Integrated Forecasting System from Cycle 43R3. It is 30-35% faster than the "McRad" scheme used in earlier cycles, and its modular design allows the spectral resolution, the description of cloud and aerosol optical properties, and the solver, to be changed independently of one another. Its offline version is well suited for use as a research tool.

ecRad is written in Fortran 90 and has been tested using the GNU, PGI and Cray compilers. A prerequisite is the NetCDF library.

Documentation

• The new scheme is described in a paper in press in JAMES (Hogan and Bozzo 2018)
• An older version is documented in ECMWF Technical Memorandum 787 (Hogan and Bozzo 2016)
• Draft User Guide for the offline version of ecRad
• Three solvers are available: McICA (Pincus et al. 2003), Tripleclouds (Hogan and Shonk 2008) and SPARTACUS (Hogan et al. 2016).
• Gas optical properties are provided by the RRTM-G model from Atmospheric and Environmental Research (AER).
• Radiation is documented in Part IV, Chapter 2 of the IFS Documentation.
• The latest version is 1.0.1: see CHANGELOG

License

The offline version of ecRad is provided under the terms and conditions of the OpenIFS licence, which is the same license as used for the full OpenIFS model.  The key points of this license are as follows

• The license is free, but it is not an open-source license (despite the name).
• Licenses are provided per institute and require an authoritative signature from the host institution. Personal licenses are not available.
• The license permits free educational and research use to research and academic institutions.
• Commercial use of the code is not permitted, nor is dissemination of real-time data products generated using the software.
• The license is perpetual: it does not need to be renewed once signed. The license can be terminated at any time by the licensee.
• Redistribution of the software (modified or unmodified) to any non-licensed institute outside the licensed institute is forbidden.

The licence is not intended to be a barrier to the use of ecRad so please get in touch with any licensing queries.

Getting started

• Please email ecrad-support@ecmwf.int to request a license, stating your name, institute, position, and a brief summary of what you would like to do with the ecRad software.
• If approved, the license agreement should be signed by a permanent employee of the institute who can take responsibility for the license conditions being met by users within the institute. To expedite the process, it is helpful if the name, email and full postal address of this person is provided at the time of the initial request.
• Once a license is granted, download access will be provided to the source code.
• Scientific and technical queries should be addressed to Robin Hogan at ecrad-support@ecmwf.int.