Air temperature changes in Barentsburg (Svalbard) in XX-XXI centuries. Justification for introducing a new climate standard

As a result of the analysis of the monthly mean values of the surface air temperature (SAT) for the entire period of regular instrumental observations in 1911-2020 in Barentsburg, climatic regimes characterizing the time intervals of stable warming / cooling are determined both for individual calendar seasons and for the year as a whole. During the study period, six climatic regimes were identified for summer, autumn and winter, four climatic regimes for spring, and eight climatic regimes for a year. For all seasons, the coldest regime occurs at the beginning of the XX century, the warmest regime - in the late XX - early XXI century. In all seasons, with the exception of the spring season, for which each subsequent regime is warmer than the previous one, there is a cooling in the 1960s. For the entire study period, the trends of changes in the seasonal and average annual SAT values are positive. For "recent” warming (with the beginning in 1986), the SAT growth rates for calendar seasons and the year as a whole are 2-4 times higher than the corresponding characteristics for the entire study period. 30-year reference period 1991-2020 contains a stable tendency to warming, objectively reflects the current specifics of the climate of the region under study and, therefore, can be considered the modern climatic norm for Svalbard.