Snow is a type of precipitation in the form of small ice particles. Snowfall rate refers to the average depth of snow that falls in a specified unit of time.
Previous UK climate scenarios (e.g. UKCIP02) provided projections of changes in snowfall rate. For UKCP09, creating probabilistic projections of changes in snowfall rate were not possible because the models sometimes project small but non-zero values in the future, implying changes relative to the baseline climate that are close to the absolute lower bound of -100%. Under these conditions, statistical contributions to the uncertainties captured in the UKCP09 methodology were found to become unrealistically large, and hence probabilistic projections were not provided.
In the absence of a UKCP09 probabilistic projection for snowfall rate, there are three possible alternative sources of projections of transient changes during the 21st century:
- the 17-member ensemble of variants of the Met Office GCM
- the 11-member ensemble of variants of the Met Office RCM
- the ensemble of other global climate models, available as part of the CMIP3 project
Data from the first two (Met Office GCM and RCM) is available from the Climate Impacts LINK project, operated by . In the case of snowfall rate, the use of changes from the 11-member Met Office RCM ensemble is recommended in the first instance.
- For variables for which probabilistic projections could not be provided, go to section 5.10 of the UKCP09 Briefing report, with more details in section 4.8 of the UKCP09 Climate change projections report.
- The 11-member RCM data is described in the Reports & guidance section, and section 5 of the UKCP09 Climate change projections report.
- More details about the climate models used are given in Box 2.1 of the UKCP09 Climate change projections report. A commentary about the strengths and weaknesses of climate models is given in Annex 3.
- For an overview of how probabilistic projections are created and presented, see Box 3 of the Briefing report. More details are in Chapter 3 of the UKCP09 Climate change projections report.
- Recent trends in wind speed are presented in Chapter 2 of the Observed trends report. Information about extreme gusts in the UK is available from the .