Circulation Mechanisms Generating Temperature Anomalies Over the Territory of Asian Russia

This paper studies the changes in winter air temperatures in the Siberian sector of the northern hemisphere (60–120° E) over a long-term period of 1947–2017. A positive trend in air temperature (0.3°C/10 years) was revealed. An analysis of the magnitude and frequency of temperature anomalies also confirms an increase in surface temperature. The distribution of large positive and negative temperature anomalies was investigated. Centers of the largest recurrence of large negative anomalies were located in the south and south-west of the study area. A maximum number of negative anomalies were observed in December. Large positive anomalies (the highest frequency in January) were observed throughout the territory under consideration, and extremely large anomalies were found only at 20% of the stations. The largest number of anomalies in the period of 1947–2017 was observed at the Irkutsk station. Based on the analysis of elementary circulation mechanisms (classification by B.L. Dzerdzeevskii), a relationship was established between the atmospheric circulation and the distribution of air temperature anomalies. It was concluded that the temperature regime in the winter months was formed under the influence of 26 elementary circulation mechanisms, combined into seven groups. The meridional circulation prevailed (75% of cases). The elementary circulation mechanisms of the meridional northern circulation group were all characterized by the presence of blockings and intrusions of southern cyclones into the study area. In general, over the past two decades, an increase in duration of macrocirculation processes resulting in the inter-latitudinal air mass exchange has been revealed.