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Spatially Coherent Projections When should I use SCPs?

  • When one wants to take into account more of the UKCP09 probabilistic range than the 11-member RCMs offer (note the SCPs do not include the full range of uncertainty included in the UKCP09 probabilistic projections).

The SCPs are generated by applying scaling factors to the 11-member RCM data so that the changes in the SCP ensemble are linearly related to change in global temperature. This is to better reflect the changes in global temperature more consistent with the wider set of uncertainties explored by UKCP09. Therefore, although the SCPs undersample the range of uncertainty available through the UKCP09 probabilistic projections, they do explore a wider range of climate change than the 11-member RCM ensemble.The SCPs could be used for a preliminary study of climate change impacts prior to a more in-depth study using the probabilistic projections.

  • When performing studies that require information from more than one grid square in a spatially coherent way
Unlike the UKCP09 probabilistic projections, the SCPs allow users to model impacts that fall over a number of neighbouring grid squares, such as modelling flow in river catchments. They are also spatially coherent, which means that corresponding values from multiple adjacent grid squares within a single ensemble member can be averaged to produce a single projection for a user-defined multi-grid square area.
  • When information for wind is required in combination with other variables

Like the 11-member RCM, the SCPs provide projections of wind alongside the other climate variables. As the UKCP09 probabilistic projections only provide fully probabilistic projections of wind speed in a separate , if a user wishes to do an analysis using wind and other variables together they will need to either use the SCPs or the 11-member RCM projections. There are also technical notes available on wind from the 11-member RCM, and also the probabilistic projections.

  • When information from both UKCP09 variable is required together

Unlike the UKCP09 probabilistic projections that provide the climate variables in 3  , the SCPs provide all climate variables in one batch. This is made possible because the computing power to generate the SCPs is not as intensive as the UKCP09 probabilistic projections. Hence all variables in the SCPs are consistent with each other and can be processed together in an impacts model.