ClimGen is a spatial climate scenario generator, designed to allow users to explore some of the uncertainties in future climate change at regional scales.
ClimGen was originally developed by Tim Osborn (Climatic Research Unit, CRU) and Tim Mitchell (then at the Tyndall Centre for Climate Change Research), both in the School of Environmental Science, University of East Anglia, Norwich, UK. ClimGen is being maintained and developed further by Tim Osborn. Other contributions (data processing, advice, testing, etc.) have been made by Craig Wallace, Ian Harris, Tom Melvin, Nigel Arnell, Rachel Warren, Rita Yu, Jeff Price and a number of others.
ClimGen is based on the so-called "pattern-scaling" approach to generating spatial climate change information for a given global-mean temperature change. The pattern-scaling approach relies on the assumption that the pattern of climate change (encompassing the geographical, seasonal and multi-variable structure) simulated by coupled atmosphere-ocean general circulation models (AOGCMs) is relatively constant (for a given AOGCM) under a range of rates and amounts of global warming, provided that the changes are expressed as change per unit Kelvin of global-mean temperature change. These normalised patterns of climate change do, however, show considerable variation between different AOGCMs, and it is this variation that ClimGen is principally designed to explore. Further scientific details are provided in the technical paper given below.
ClimGen also provides a convenient interface for generating these scenarios and for extracting observed climate data in a common format, with options to extract user-defined regions, seasons and specific time periods.
In some respects, ClimGen is similar to other spatial scenario generators that use the pattern-scaling approach, some of which are listed in the technical paper given below. Similar tools have previously been developed at CRU/UEA -- notably SCENGEN. Information about SCENGEN version 2.x (Wigley et al., 2000; Hulme et al., 2000) is available here (archived copy). SCENGEN was subsequently developed further by Tom Wigley at NCAR, Boulder, Colorado, USA, and information about SCENGEN version 4.x (Wigley, 2003) was available here (archived copy). ClimGen does not re-use any of the SCENGEN software code, and only uses the concepts from SCENGEN that are common to all tools of this type.
The scientific and technical basis for ClimGen is described in the following paper and references therein:
A user manual for ClimGen is available:
Explanations of file names and file formats:
Explanation of the global temperature change database available in ClimGen: global temperature table
ClimGen is written in Fortran95 and the source code is available for use in selected projects. See source code for more details if you wish to obtain this software.
A wide range of datasets have been generated using ClimGen for many projects (see papers listed later). Some have been shared via this website, so they are listed here to provide an archive in case those studies need to be reproduced.
ClimGen was used in the EU ToPDAd project.
ClimGen was used in the NERC QUEST-GSI (Global-Scale Impacts) project.
ClimGen was used in the EU ERMITAGE project.
These papers were based partly or fully on scenarios generated using the ClimGen pattern-scaling methods and software.
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The ClimGen software system is made available under the Creative Commons CC BY-NC-ND License. You may use, copy and redistribute the ClimGen software system under the following terms: Attribution (give appropriate credit and link to this license), Non-Commercial (you may not use it for commercial purposes), and No Derivatives (you may not distribute any modified versions).
The datasets generated using ClimGen are made available under the Open Database License. Any rights in individual contents of the datasets are licensed under the Database Contents License under the conditions of Attribution and Share-Alike.
Updated: February 2024, Tim Osborn