Provenance & quality
The PET (mm/day) was calculated by applying the Penman-Monteith equation  for a well-watered grass surface  to the air temperature, specific humidity, downward long- and shortwave radiation and surface air pressure from the Climate hydrology and ecology research support system meteorology dataset (CHESS-met) . To calculate PETI (mm/day) an interception correction is applied on days with non-zero rainfall, by interpolating between PET and potential interception assuming an exponential dry-down. On dry days the PETI is equal to the PET. The PETI is calculated using all of the same input variables as the PET, as well as the precipitation from the CHESS-met dataset, which is the CEH-Gridded Estimates of Areal Rainfall (CEH-GEAR) daily rainfall estimates [4,5] scaled to units of kg m-2 s-1. The PET and PETI data were created using software developed in python. For further detail see the Supporting Documentation.
This version of the CHESS-PE dataset differs from the previous version (1961-2012) only by temporal coverage. That is, previous years' data have not been modified.
 Monteith, J. L.: Evaporation and environment, in: 19th Symposia of the Society for Experimental Biology, University Press, Cambridge, 1965
 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.
 Robinson, E. L., Blyth, E., Clark, D. B., Finch, J., Rudd, A. C. (2016). Climate hydrology and ecology research support system meteorological dataset (1961-2015) [CHESS-met] . NERC-Environmental Information Data Centre https://doi.org/10.5285/10874370-bc58-4d23-a118-ea07df8a07f2
 Tanguy, M.; Dixon, H.; Prosdocimi, I.; Morris, D. G.; Keller, V. D. J. (2016). Gridded estimates of daily and monthly areal rainfall for the United Kingdom (1890-2015) [CEH-GEAR]. NERC Environmental Information Data Centre. https://doi.org/10.5285/33604ea0-c238-4488-813d-0ad9ab7c51ca
 Keller,V. D. J., Tanguy, M. , Prosdocimi, I. , Terry, J. A. , Hitt, O., Cole, S. J. , Fry, M., Morris, D. G., Dixon, H. (2015) CEH-GEAR: 1km resolution daily and monthly areal rainfall estimates for the UK for hydrological use. Earth Syst. Sci. Data Discuss., 8, 83-112 https://doi.org/10.5194/essdd-8-83-2015.