Clipping

The process used in UKCP09 to exclude tails (or outliers) from the sampled data.

In detail

The method developed by the Met Office Hadley Centre to derive probabilistic climate projections is designed to span the full range of uncertainty. But there are issues in the tails because a number of statistical processing steps are combined and the statistical approximations can have a large influence on the tails of the distribution.

It has been judged that clipping to the 1st and 99th probability levels (i.e. not providing extreme projections that fall outside of these bounds) will exclude data in the tails which are unreliable.

Find out more

• FAQ: What is clipping and why has it been done? What are the implications for use?