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Diagram showing climate predictions. : This link opens in a new window
Diagram showing climate predictions.


Using the QUMP ensemble with PRECIS

Boundary data from a 17-member perturbed physics ensemble are now available for use in PRECIS experiments.  This will allow PRECIS users to explore the model uncertainty in the projections of future climate change in their region.  The 17 models are based on the Met Office Hadley Centre's HadCM3 model and are referred to as HadCM3Q0-16.

Downscaling 17 GCMs with PRECIS would require very large inputs of computing resources, data storage and data analyses.  In order to explore the range of uncertainties while minimising these requirements, we recommend that PRECIS users select of sub-set of 4-6 the ensemble members in their experiments. 

Multi-annual mean for key variables are available from the British Atmospheric Data Centre (BADC), and PRECIS users can use these data to identify models that (a) simulate key features of the climate in their region realistically and (b) sample the range of outcomes of future change of the full 17-member ensemble.  Making a good selection of models is important in order to draw robust conclusions about uncertainty - so it is important that you allow enough time/resource for this analysis before you start running your simulations.

  Selecting GCMs to Downscale Selecting GCMs to Downscale (PDF, 305 kB)  - A short document that gives some guidance about the criteria you might use to make your sub-selection.

Requesting Boundary data for HadCM3Q0-16

If you are a PRECIS user who is interested in undertaking uncertainty analyses with the QUMP ensemble, please contact precis.

The PRECIS team will ask you to undertake your own analysis of the GCM fields held at BADC in order to select a sub-set of the ensemble.  When you have done this, please send the PRECIS team a 1-2 page document describing your sub-selection methods and choices.  We can then provide you with further guidance and the requested boundary data.

If you are undertaking experiments that require boundary conditions for the full 17-member ensemble and have good scientific reasons for doing so, then please contact us and we will consider your request.

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Last Updated: 30 July 2013