UKCP18 Local
UKCP18 Local is the dataset that tells the IMP what the weather might look like decades from now. It is part of the UK Climate Projections 2018 suite, produced by the Met Office.
What it provides
| Model | Convection-Permitting Model, from the UKCP18 suite |
| Native resolution | 2.2 km |
| Also available on | A 5 km grid |
| Best suited to | Local and hourly climate extremes |
The projections give high-resolution information suitable for analysing local and hourly climate extremes (Met Office, 2019).
Why "convection-permitting" matters
The term is doing real work, and it is worth unpacking.
Most climate models run on grids too coarse to represent convection, the process that drives intense summer downpours. Those models have to approximate it, and the approximation tends to smooth away exactly the short, sharp, localised rainfall that floods a road.
A convection-permitting model runs at a fine enough resolution to simulate that process directly rather than approximating it. For the IMP, that is the difference between a projection that can plausibly drive a flood model and one that cannot.
Why the IMP needs this resolution
The hazard models downstream work at 20-minute intervals over individual urban catchments. A coarse projection would have nothing meaningful to say at that scale.
How it is used in the IMP
UKCP18 Local supplies the future rainfall and temperature projections that feed the weather generator. The generator combines them with observed historical records to produce the future weather the hazard models actually run on.
Inputs and outputs to be confirmed
The handbook lists "required input data" and "generated output data" for UKCP18 Local as headings without content. Those details have not been supplied yet and will be added here when they are.