What does the data show? This data shows the monthly averages of rainfall amount (mm) for 2040-2069 using a combination of the CRU TS (v. 4.06) and UKCP18 global RCP2.6 datasets. The RCP2.6 scenario is an aggressive mitigation scenario where greenhouse gas emissions are strongly reduced. The data combines a baseline (1981-2010) value from CRU TS (v. 4.06) with a percentage change relative to 1981-2010 from UKCP18 global. Where the baseline value was <1mm/month, the projection value has been replaced with 'Null' because the percentage change may be unreliable with a very small baseline. The data is provided on the WGS84 grid which measures approximately 60km x 60km (latitude x longitude) at the equator. Limitations of the data We recommend the use of multiple grid cells or an average of grid cells around a point of interest to help users get a sense of the variability in the area. This will provide a more robust set of values for informing decisions based on the data. What are the naming conventions and how do I explore the data? This data contains a field for each month’s average over the period. They are named 'pr' (precipitation), the month and ‘upper’ ‘median’ or ‘lower’. E.g. ‘pr Mar Lower’ is the average of monthly-total rainfall in March throughout 2040-2069, in the second lowest ensemble member. To understand how to explore the data, see this page: https://storymaps.arcgis.com/stories/457e7a2bc73e40b089fac0e47c63a578 Please note, if viewing in ArcGIS Map Viewer, the map will default to ‘pr Jan Median’ values. What do the ‘median’, ‘upper’, and ‘lower’ values mean? Climate models are numerical representations of the climate system. To capture uncertainty in projections for the future, an ensemble, or group, of climate models are run. Each ensemble member has slightly different starting conditions or model set-ups. Considering all of the model outcomes gives users a range of plausible conditions which could occur in the future. To select which ensemble members to use, the monthly averages of precipitation for the period 2040-2069 were calculated for each ensemble member and they were then ranked in order from lowest to highest for each location. The ‘lower’ fields are the second lowest ranked ensemble member. The ‘upper’ fields are the second highest ranked ensemble member. The ‘median’ field is the central value of the ensemble. This gives a median value, and a spread of the ensemble members indicating the range of possible outcomes in the projections. This spread of outputs can be used to infer the uncertainty in the projections. The larger the difference between the lower and upper fields, the greater the uncertainty. Data source CRU TS v. 4.06 - (downloaded 12/07/22) UKCP18 v.20200110 (downloaded 17/08/22) Useful links Further information on CRU TS Further information on the UK Climate Projections (UKCP) Further information on understanding climate data within the Met Office Climate Data Portal
Overview2040-206960kmCRU TS v.4.06 and UKCPClimateGlobalMet OfficePrecipitationProjectionsaveragemonthly
Additional Information
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dcat_issued2022-08-23T09:46:06.000Z
dcat_modified2022-09-01T12:27:52.758Z
dcat_publisher_nameMet Office
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harvest_source_titleMet Office Climate Data Portal