Assessment of trends of air temperature based on 140-year observations of V.A. Mikhelson Meteorological Observatory

The article deals with the test of the main hypothesis about regional climate warming based on the analysis of unique continuous long-term observations of air temperature in 1879-2018 at V.A. Mikhelson meteorological observatory. The authors present annual and seasonal trends of air temperature for 140 years, which indicate its increase practically during the entire observation period. All considered statistical series can be characterized by the normal distribution of random variables. The cyclical nature of changes in air temperature for all series relative to their long-term average values and a period of a clear significant increase in temperature, which falls on the last three decades of both annual values and seasonal time intervals, have been revealed. Statistical criteria determined a clearly heterogeneous pattern of this period in relation to both the previous observation years and the entire 140-year period; in particular, its average air temperature is quite higher, which proves the warming of the region's climate over the past decades. It has been noted that the degree of air temperature rise in winter is higher than in summer. Positive changes in the elements of the heat balance, both during the growing season and throughout the year, in particular, the improvement of the conditions for overwintering agricultural crops, predetermines the need for research in the possible expansion of their varieties for cultivation in the Moscow region. Based on a comprehensive analysis and logical conclusions, we made a hypothesis about the influence of intensive development of heated buildings around the meteorological station on the air temperature rise in the last half century; however, it is impossible to measure such an influence today, as well as the influence of global warming due to other factors.