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UKCP09 Guidance
Products
Published material
Customisable images
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Shapefile format
Shapefiles are available as an export format via the UKCP09 User Interface. They are available for any gridded variable for which a map is available (excluding maps of aggregated areas). They are accessed through the output page of the User Interface by selecting the shapefile option from the drop-down selection when saving your request.
Careful consideration and caution is required when working with the shapefiles, in order to ensure that the results of any work you do with the data in a GIS are scientifically valid. This section outlines the ways in which the data can and should not be used.
In addition to shapefiles of the projections data, shapefiles are also available for each of the grids used in UKCP09 and are available here. Please note that you will be asked to log-in to the User Interface to access the page.
How can I use them?
Shapefiles provide a useful means of enabling the UKCP09 data to be loaded into GIS software and combined with other data layers to provide context and for visualization and analysis purposes. The nature of the data means that it is not scientifically valid to use two different UKCP09 variables at the same (or different) probability level, in an analysis.
GIS can be a useful tool for establishing and visualising the range of uncertainty within and across emission scenarios, i.e. mapping ranges.
Within a given emissions scenario, it would be a valid exercise to map the range of uncertainty for a given variable, i.e. to visualise the range between the 10% and 90% probability levels for summer mean temperature for a given emissions scenario (other ranges can be explored depending on the purpose, for example some users may wish to explore the 33% to 67% range).
If a user were interested in visualising the full range of uncertainty for a given climate variable i.e. across all emissions scenarios, it would be possible to do this in a GIS. This would be achieved by subtracting the value of the climate variable at the 10% probability level for the low emissions scenario from the value of the 90% probability level for the high emissions scenario. This would result in a map of the total range of uncertainty.
The above two cases represent the only situations where it is valid to use the UKCP09 data to establish ranges.
What shouldn’t I use them for?
The GIS Shapefiles were created using the CDF data with each shapefile containing data for one probability level. As such, guidance in terms of how these shapefiles can and should not be used within a GIS approach is the same as that for the CDF data itself.
Visualisation and analysis of the UKCP09 shapefile data within a GIS approach must consider that the data is not presenting a snapshot of a distribution of the climate at a particular time with all the grids square values spatially coherent (see this FAQ). A UKCP09 map does not provide the same information as that provided by a Weather map or a map of observed climate data and should not be analysed and interpreted as such.
Maps created using the shapefile data should be interpreted like other UKCP09 maps. For guidance on this please refer to this section.
Further information
For more information about how to interpret customised maps click here.
Please refer to the following section of the Climate Change projections report for information on how to interpret probabilistic climate change maps.
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