Atmospheric Centers of Action in the Northernand Southern Hemispheres: Features and Variability
И. И. Мохов, А. V. Chernokulsky, Alexander Osipov
Abstract
An analysis is carried out to estimate features of the atmospheric centers of action (ACA) in the Northern and Southern hemispheres using different long-term reanalysis data. The variability of ACAs and their relation to the hemispheric temperature and key climatic modes, including the El Niño–Southern Oscillation, Atlantic Multidecadal Oscillation, and Pacific Decadal Oscillation is analyzed. According to long-term data, it is found that the centennial hemispheric warming is accompanied by a significant weakening of the polar highs and the Greenland High that is more significant in summer. The deepening of the Icelandic Low, especially in summer, and the Aleutian Low, especially in winter, is shown. A significant weakening of the winter Siberian and North American highs and a deepening of the summer North American Low are also revealed. In the Southern Hemisphere, all three subpolar oceanic lows and the Mascarene High significantly intensify under warming conditions, while the summer Australian and South African lows weaken.