Аннотация:A two-zone model of the atmospheric circulation over a hemisphere is considered. The latitude φ of the boundary between
the zone of the Rossby circulation regime at mid and high latitudes and the zone of the Hadley circulation regime at low
latitudes serves as a model variable. The principle of maximum of the (information) entropy of the eddy regime within
the Rossby regime zone is used to determine a statistical (climatic) equilibrium value of φ. Based on the proposed model,
the question of atmospheric blocking action over the hemisphere is addressed. An attempt has been made to represent a
blocking phenomenon as a necessary attribute of the atmospheric circulation in statistical equilibrium. The model suggests
that long-term climate change related either to the (significant) global warming or to the (significant) global cooling, both
respective to the current climate state, and quantified in terms of changes in latitude φ, leads to an increase in the probability
of blocking action.