Connections between climatic characteristics and cyclonic activity in winter over Siberia in 1976–2011

Resumo

The temperature, surface pressure, and cloud cover for Siberia (50°–70° N; 60°–110° E) in the winter period (December–February) are estimated over 1976–2011 based on data from 163 meteorological stations. Using surface synoptic maps, time series of winter cyclone characteristics, such as the total number and central pressure, are derived for the same period. Two time intervals are found in variations of climatic characteristics and cyclone activity characteristics: 1976–1990 and 1991–2011. In the first period, the temperature and cloud cover increased and the surface pressure fell, which reduced the number of cyclones and intensified (deepened) them. In the second period, opposite trends took place. The correlation analysis between the climate variables and cyclonic activity characteristics allowed us to consistently describe the impact of cyclones on the surface pressure and cloudiness.