பூமி அறிவியல் & காலநிலை மாற்றம் இதழ்

சுருக்கம்

Fluctuations of the Global Atmospheric Circulation in the XX-XXI Centuries

Nina K Kononova*

Fluctuations in the global atmospheric circulation in 1899-2014, in the classification by BL Dzerdzeevskii considered. Three circulation epochs are identified. Frequency elementary circulation mechanisms (ECM) in each period analyzed. ECM, the total duration of which an average of more than six months era, marked. The start date of circulation seasons in the northern and southern hemispheres and their duration for each year are determined. Long-term fluctuations in mean annual air temperature in the Northern and Southern hemispheres and the global and the annual amplitude of air temperature due to changes in the nature of atmospheric circulation are analyzed. Particular attention is paid to the modern period (1998-2014). During this period, in the lower troposphere maximum meridional transport of air masses is observed (on average 335 days per year). In 93 days on average per year macro processes cyclones at the poles, without blocking processes, with three or four cyclones outputs of low to high latitudes in each hemisphere observed (type 13). On other days macro processes with anticyclones at the poles, the outputs of the cyclone low to high latitudes in two-four quadrants of each hemisphere and the Arctic-Antarctic invasions in their rear, forming a blocking process (types 8 to 12) are marked. As a result, the average annual air temperature in the Northern Hemisphere has ceased to rise, and in the Southern Hemisphere air temperature dropped slightly. Due to the growth of the length of the high pressure in winter and summer annual amplitude of air temperature was the highest for the entire observation period. Simultaneous outputs cyclones from low to high latitudes in different sectors hemispheres ‘odnovpemennoe’ cause the occurrence of natural hazards associated with heavy rainfall in different regions of the Earth.