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Timescaling

'Timescaling' is a method used to create transient (continuous) climate simulations.

In detail

Timescaling is a method for combining information from equilibrium and transient simulations by scaling equilibrium response patterns to augment transient simulations and thereby obtain probability distribution functions of transient regional changes in a variable (e.g. surface temperature and precipitation).

Large ensembles of coupled atmosphere-ocean general circulation model (AOGCM) simulations are required to explore modelling uncertainty and make probabilistic projections of future transient climate change at regional scales.

These large ensembles are not yet computationally feasible, so a technique has been developed to emulate the response of such an ensemble by scaling equilibrium patterns of climate change derived from much cheaper 'slab' model ensembles, in which the atmospheric component of an AOGCM is coupled to a mixed-layer ocean. Timescaling permits sampling of modelling uncertainty in a way that is not possible with AOGCM projections given present day computing resources.

Find out more

  • An overview of how probabilistic projections are created and presented in UKCP09 is described in  of the UKCP09 Briefing Report.
  • More details are provided in Chapter 3 of the UKCP09 Climate Change Projections report, including an overview of the methodology in . The dynamical downscaling approach used is explained in more detail in .
  • A comparison of the UKCP09 methodology with an alternative method is described in , and summarised in  of the UKCP09 Briefing Report.