In this work, we studied variations in the atmospheric characteristics at high latitudes of the Northern Hemisphere associated with a powerful burst of solar activity in the period of January 13–23, 2005, which caused a series of solar proton events, strong magnetic storms, and a deep Forbush decrease of galactic cosmic rays. It is shown that this burst was accompanied by a significant disturbance of the middle and lower atmosphere at high latitudes. The most pronounced changes in the stratospheric circulation (a sharply intensified stratospheric polar vortex) occurred on January 15–19. It coincided with a considerably increased ionization rate in the mesosphere and upper stratosphere, as well as with an increase of the North Atlantic Oscillation index and a weakening of the planetary wave activity. In the lower atmosphere, an intensive regeneration of cyclones was observed near the south-eastern coast of Greenland. Intensification of the polar vortex was accompanied by a noticeable decrease of temperature (by ~10 K) in the stratosphere at latitudes 70°N. A further sharp weakening of the vortex in late January contributed to the onset of a process close to a sudden stratospheric warming. The results of the study suggest that the development of observed atmospheric disturbances was possibly influenced by phenomena associated with a sharp increase in the flare activity on the Sun during January 13–23, 2005, including a series of powerful solar proton events that considerably increased the ionization rate in the middle atmosphere.
S.V. Veretenenko (Wed,) studied this question.