11-member RCM: technical notes
This page provides technical notes about the 11-member RCM.
1. Technical note on projections of lightning
Key findings for lightning projections by 2080s (medium emission scenario):
- Increase in the number of lightning days across the UK for all seasons.
- Projected increases are largest in summer. There is a north-south gradient of change with projected increase greatest in Scotland and Northern Ireland and smallest in south east England.
- Projected increases in autumn are largest over south England and Wales.
- Projected increases in spring and winter are small in all locations.
Download the Technical Note on Future change in lightning [4Mb] in the 11-member RCM.
2. Technical note on snow projections
Key findings for snow projections by the 2080s (medium emission scenario):
- Mean of the ensemble shows reductions in snow days in all regions.
- Largest reductions (typically >70%) occur in spring and autumn, with reductions of 40-70% in winter.
- Reductions are smallest for the highlands of Scotland.
- The general pattern of heavy snow events shows large reductions but with greater intra-ensemble uncertainty.
- For the whole of the UK the reductions in heavy snow events may be >80% for winter and autumn while reductions in spring may be >40%.
Download the Technical Note on Interpretation and use of snow projections [1Mb] from the 11-member RCM.
3. Technical note on fog projections
Key findings for fog projections by 2080s (medium emission scenario):
- Projected changes in winter are for a decrease in fog of >50% in north Britain and north Wales with increases of 1-30% over south and central England.
- Projected changes in spring are similar to winter in pattern but exhibit greater reductions.
- Projected changes for summer show large reductions across the UK.
- Project changes for autumn show reductions of 10-30% across the UK with greater reductions over the Scottish highlands.
Download a Technical Note on the Future frequency of fog [3Mb] from the 1-member RCM.
4. Technical note on surface wind speed
As wind speed data was not available directly from the initial UKCP09 results, the Met Office provided a Technical note [1Mb] that provides information on surface wind speed from the 11-member RCM.
Key findings for surface wind speed under the medium emission scenario are:
- The 11-member RCM projections show lower than observed wind speeds over mountainous regions of Scotland and Wales, and higher than observed wind speeds over low-lying regions of England.
- The 11-member RCM provides time series and distributions of daily wind speed which replicate observed characteristics more realistically than in their driving global climate model simulations.
- Projected future changes in 30 year averages are relatively small within the RCM ensemble.
- Seasonal changes at individual locations across the UK lie within the range of -15% to +10%.
A supplement to the wind speed note [334kb] was added in October 2010.