This dataset is a model output created using the BGS AquiMod model. It provides monthly groundwater level relative to the Ordnance Datum (maOD) from 1891 to 2015, reconstructed for 54 observation boreholes across the UK. Based on the Generalised Likelihood Uncertainty Estimation (GLUE) methodology, 90th percentile and 10th percentile confidence bounds have been estimated and are given for each of reconstructed groundwater level time series. Full details about this dataset can be found at https://doi.org/10.5285/ccfded8f-c8dc-4a24-8338-5af94dbfcc16

Monthly and daily 5km gridded Potential Evapotranspiration (PET) data for the UK. PET was derived using temperature-based equation from McGuinness-Bordne calibrated for the UK (calibration period: 1961-1990). The units are mm/day for daily PET and mm/month for monthly PET. The dataset covers the period from 1891-2015. For both subsets (daily and monthly), a set of performance metrics were calculated, which are provided together with the PET grids. The list of metrics provided is: Mean Absolute Percent Error (MAPE), Nash-Sutcliffe Efficiency (NSE), Kling-Gupta Efficiency (KGE), Correlation Coefficient, Variability Ratio (VR), Bias Ratio and monthly MAPE. Full details about this dataset can be found at https://doi.org/10.5285/17b9c4f7-1c30-4b6f-b2fe-f7780159939c

Monthly Standardised Groundwater level Index (SGI) for observation boreholes across the UK from 1891 to 2015, based on reconstructed groundwater level time series (Bloomfield et al., 2018; https://doi.org/10.5285/ccfded8f-c8dc-4a24-8338-5af94dbfcc16). Standardised groundwater levels have been estimated using a non-parametric normal scores transform of groundwater level data for each calendar month. Probability estimates of an SGI being less than 0, -1, -1.5 and -2 are also provided. Full details about this dataset can be found at https://doi.org/10.5285/d92c91ec-2f96-4ab2-8549-37d520dbd5fc