These data represent five high-latitude sites studied in the PAGE21 project (https://www.page21.eu): Samoylov, Kytalyk, Abisko, Zackenberg and Bayelva. Please see the linked manuscript for details of the sites. These are meteorological driving data, which were prepared using observations from the sites combined with reanalysis data for the grid cell containing the site. For the period 1901-1979, Water and Global Change forcing data (WFD) were used (Weedon et al., 2011). This has half-degree resolution for the whole globe at 3-hourly time resolution from 1901 to 2001. For the period 1979-2014, WATCH-ForcingData-ERA-Interim (WFDEI) was used (Weedon, 2013). For the time periods in which observed data were available, correction factors were generated by calculating monthly biases relative to the WFDEI data. These corrections were then applied to the time series from 1979 to 2014 of the WFDEI data. The WFD before 1979 were then corrected to match these data and the two datasets were joined at 1979 to provide gap-free 3-hourly forcing from 1901 to 2014. Local meteorological station observations were used for all variables except snowfall, which was estimated from the observed snow depth by treating increases in snow depth as snowfall events with an assumed snow density. See linked manuscript for more details.

Variables provided: Air temperature Specific humidity Wind speed Incoming shortwave radiation Incoming longwave radiation Surface pressure Rainfall (both CRU and GPCC) (https://crudata.uea.ac.uk/cru/data/hrg/ ; https://climatedataguide.ucar.edu/climate-data/gpcc-global-precipitation-climatology-centre) Snowfall (both CRU and GPCC) Both corrected and uncorrected precipitation variables are provided. The data that were used in the linked publication were "Snowf_GPCC_cor" and "Rainf_GPCC_cor".

Supplement to: Chadburn, Sarah; Krinner, Gerhard; Porada, Philipp; Bartsch, Annett; Beer, Christian; Belelli Marchesini, Luca; Boike, Julia; Ekici, Altug; Elberling, Bo; Friborg, Thomas; Hugelius, Gustaf; Johansson, Margareta; Kuhry, Peter; Kutzbach, Lars; Langer, Moritz; Lund, Magnus; Parmentier, Frans-Jan W; Peng, Shushi; van Huissteden, Jacobus (Ko); Wang, Tao; Westermann, Sebastian; Zhu, Dan; Burke, Eleanor J (2017): Carbon stocks and fluxes in the high latitudes: using site-level data to evaluate Earth system models. Biogeosciences, 14(22), 5143-5169