Isoscape of precipitation weighted annual mean tritium activities across the Adriatic-Pannonian Region (1976-2017); AP3H_v1 database

Precipitation weighted annual mean tritium activities have been calculated from tritium records of 41 precipitation stations covering the Adriatic-Pannonian Region with a focus on Slovenia and Hungary. The monthly 3H data were checked for database errors via sequential univariate outlier detection on the amount-weighted annual averages. If more than 15% of the annual sum precipitation amount did not have corresponding tritium measurements at a given station, then it was discarded from interpolation for the sake of result robustness. The final data density allowed to establish interpolated (1 x 1 km) products using point kriging. The weights for kriging were obtained from Gaussian semivariograms assuming isotropy. The 42 annual grids were combined into the AP3H_v1 database. For out-of-sample verification of the data and further details, the user is referred to the accompanying data description paper. Tritium concentrations are expressed in tritium units (TU; 1TU = 0.118 Bq kg^-1^)