Weather and climate features of the Northern Hemisphere in 2019 in the context of long-period variability

The features of the spatial and temporal distribution of the main meteorological values in the Northern Hemisphere in 2019 are considered. A brief description of climate change on the background of long-period variability of extreme meteorological phenomena, which identified by WMO climate indices, is given. Quartile analysis and nonparametric Mann-Kendall criterion are used to assess the significance of changes in the frequency and intensity of extreme meteorological phenomena in different regions of Russia. The increase in the growth of the average temperature in the Northern Hemisphere in the spring and summer of 2019 compared to 2018 and early 2019 is noted. The prolonged large-scale anomalies of weather regimes were observed in the warm period of 2019: heatwaves in Western Europe, in the south of European Russia, in Siberia, Alaska, and as well heavy rainfall in the Irkutsk region and in the south of the Far East. Possible mechanisms of weather and climate changes in the Northern Hemisphere are discussed. The focus is on the Arctic, which is the most vulnerable to climate warming. It is concluded that, with an abundance of physical hypotheses, there are many contradictions and uncertainties in the study of the mechanisms of weather and climate variability. Solving the problems requires further research based on modern technologies, the development of satellite monitoring systems and hydrodynamic modeling.