CHESS Explorer

The Climate, Hydrology and Ecology research Support System (CHESS) is a 1km gridded meteorological and land state dataset for Great Britain.

The meteorological data is used as driving data for the JULES (Joint UK Land Environment Simulator) land surface model. It also includes Potential Evapotranspiration (PET) data calculated using the Penman-Monteith equation, both with and without corrections for water intercepted by the canopy. The entire dataset is freely available for download and use for research purposes (see below).

This is a new dataset which has a wide range of uses across the environmental sciences, in addition to use with the JULES model. For instance, it has been used to study how spatial and temporal variation of climate variables impact such diverse areas as river flow, natural capital, water quality, insect-borne diseases, bird populations and more. The CHESS Explorer application provides the ability for users to preview this data, visualise maps of the different variables, and understand how they vary across the country and through time.

Launch the CHESS Explorer

The current version of the CHESS Explorer allows the user to produce, plot and download a short time series of a selected variable. The variable might be for an individual grid cell or aggregated over a user defined area.

The data within the CHESS portal consist of daily mean meteorological variables (averaged from 09:00 GMT to 09:00 GMT the next day) and daily potential evapotranspiration. The meteorological variables are largely derived from the Met Office 40km gridded MORECS dataset (Thompson et al, 1981 [6]; Hough et al, 1997 [3]), as well as the CRU TS 3.21 (Harris et al, 2014[2]) and WATCH Forcing Data (Weedon et al, 2011[7]) datasets. These are downscaled, based on topographic information, to a 1km grid (Robinson et al, in review[5]). The precipitation data are based on the CEH-GEAR dataset (also available through the UK Rainfall application) (Keller et al, 2015[4]), adjusted to the units required for the JULES model. The PET variables are calculated from the meteorological variables using the Penman-Monteith equation for a well-watered grass surface, following the Food and Agriculture Organisation of the United Nations (FAO) guidelines for computing reference crop PET (Allen et al, 1998[1]). The PET with interception correction is calculated assuming that on days with precipitation, a proportion of the evaporation is from intercepted water on the canopy, and transpiration is inhibited (Robinson et al, in review[5]).

The following meteorological variables are provided:

Near surface air temperature (1.2m) degrees K
Daily temperature range degrees K
Precipitation – GEAR kg m-2 s-1
Near-Surface Wind Speed (10m) m s-1
Surface Downwelling Shortwave Radiation W m-2
Surface Downwelling Longwave Radiation W m-2
Near-Surface Specific Humidity (1.2m) kg kg-1
Surface Air Pressure Pa
Potential evapotranspiration over well-watered grass mm/day
Potential evapotranspiration with interception correction mm/day

Accessing the data

The data are freely downloadable from the Environmental Information Data Centre. Terms and conditions of use apply to all of the datasets and you must ensure that the data are cited in the reference list of any reports or publications in which the data have been used.

While the data are freely usable for research purposes and for commercial internal business use, those wishing to build commercial services directly from CEH data are required to contact CEH data licensing.

Climate hydrology and ecology research support system meteorology dataset for Great Britain (1961-2015) [CHESS-met] v1.2

Licence terms and conditions

Climate hydrology and ecology research support system potential evapotranspiration dataset for Great Britain (1961-2015) [CHESS-PE]

Licence terms and conditions

In addition, web-services are available to enable the integration of CHESS data within other applications. Programmatic access to the data to enable further analysis, and integration with other datasets has been set up.

We expect to make CHESS model outputs, from the 1km implementation of JULES, available in the near future

Citing the data

If you use the data in reports or publications, you must cite them in references as follows:

Robinson, E.L. ; Blyth, E. ; Clark, D.B. ; Comyn-Platt, E. ; Finch, J. ; Rudd, A.C. (2017). Climate hydrology and ecology research support system meteorology dataset for Great Britain (1961-2015) [CHESS-met] v1.2. NERC Environmental Information Data Centre.

Robinson, E.L.; Blyth, E.; Clark, D.B.; Comyn-Platt, E.; Finch, J.; Rudd, A.C. (2016). Climate hydrology and ecology research support system potential evapotranspiration dataset for Great Britain (1961-2015) [CHESS-PE] . NERC Environmental Information Data Centre.

See for more information


Allen, R. G., Pereira, L. S., Raes, D., and Smith, M.: Crop evapotranspiration - Guidelines for computing crop water requirements, Food and Agriculture Organization of the United Nations, Rome, Italy, FAO Irrigation and Drainage Paper, 1998.

Harris, I., Jones, P. D., Osborn, T. J., and Lister, D. H.: Updated high-resolution grids of monthly climatic observations - the CRU TS3.10 Dataset, International Journal of Climatology, 34, 623-642,, 2014

Hough, M. N., and Jones, R. J. A.: The United Kingdom Meteorological Office rainfall and evaporation calculation system: MORECS version 2.0-an overview, Hydrology and Earth System Sciences, 1, 227-239,, 1997

Keller, V. D. J., Tanguy, M., Prosdocimi, I., Terry, J. A., Hitt, O., Cole, S. J., Fry, M., Morris, D. G., and Dixon, H.: CEH-GEAR: 1 km resolution daily and monthly areal rainfall estimates for the UK for hydrological use, Earth Syst. Sci. Data Discuss., 8, 83-112,, 2015

Robinson, E. L., Blyth, E. M., Clark, D. B., Finch, J., and Rudd, A. C.: Trends in evaporative demand in Great Britain using high-resolution meteorological data, Hydrol. Earth Syst. Sci. Discuss.,, in review, 2016.

Thompson, N., Barrie, I. A., and Ayles, M.: The Meteorological Office rainfall and evaporation calculation system: MORECS, Meteorological Office, Bracknell, 1981

Weedon, G. P., Gomes, S., Viterbo, P., Shuttleworth, W. J., Blyth, E., Osterle, H., Adam, J. C., Bellouin, N., Boucher, O., and Best, M.: Creation of the WATCH Forcing Data and Its Use to Assess Global and Regional Reference Crop Evaporation over Land during the Twentieth Century, J Hydrometeorol, 12, 823-848,, 2011