Spatially Coherent Projections
- That each of the 11 runs of the SCPs are equally plausible.
Unlike the UKCP09 probabilistic projections, there has been no weighting placed on the model projections in order to provide a probabilistic distribution.
Because of this assumption, it is recommended that SCP data be checked as to where each ensemble member lies within the UKCP09 probabilistic distribution. Such an assessment can provide an evaluation of the proportion of the full probabilistic range that is explored by the SCP data.
- That projected changes in climate are stationary across a given 30-year time period
It may be misleading to think of the projected change of a particular climate variable, as being representative of the whole 30-year time period . It is the average for that 30-year time period (as are the values for the baseline (1961–1990) 30-year time period).
For example, if there is a linear trend in the way precipitation amount is projected to evolve over time, then it is likely that the average value reported for a given 30-year period, is more likely to be observed in the middle than the first or last decade, of the 30-year period. However, because we do not know for sure what the form of the trend will be (and thus cannot assume linearity across the 30-year period), it is suggested that all of the 30-year overlapping periods that include the period of interest should be used. For example, if one were interested in the 2050s we would suggest looking at the average values for the two overlapping time periods of the 2040s and 2060s, in addition to the 2050s.