as days shorten. In the process of the Siberian High's formation, the upper-level jet is transferred across northern Eurasia by adiabatic cooling and descending advection, which in extreme cases creates "cold domes" that outbreak over warmer parts of East Asia. In spite of its immense influence on the weather experienced by a large proportion of the world's population, scientific studies of the Siberian High have been late in coming, though variability of its behavior was observed as early as the 1960s. However, recent studies of observed global warming over Asia have shown that weakening of the Siberian High is a prime driver of warmer winters in almost all of inland extra-tropical Asia and even over most parts of Europe, with the strongest relationship over the West Siberian Plain and significant relationships as far west as Hungary and as far southeast as Guangdong. Precipitation has also been found to be similarly inversely related to the mean central pressure of the Siberian High over almost all of Eastern Europe during the boreal winter, and similar relationships are found in southern China, whilst the opposite correlation exists over the Coromandel Coast and Sri Lanka. Other studies have suggested that the strength of the Siberian High shows an inverse correlation with the high-pressure systems over North Africa. Another correlation has been noted, a connection of a weaker Siberian High and Arctic oscillation when the Antarctic oscillation (AAO) is stronger. Because increased snow and ice cover enhances the Siberian High, the Siberian High was both more intense and located further west during the early Middle Pleistocene as a result of the extensive glaciation of mountain ranges across Central Asia. The decrease in magnitude of the Siberian High during the Holocene enabled eastward encroachment of westerlies enriched with water vapour, precipitating an increase in low altitude afforestation of Central Asia. See also Siberian Express Arctic dipole anomaly Cold wave North American High Polar vortex Aleutian Low References Anticyclones Climate of Asia Climate of Europe Climate of Russia Climate change in Russia Climate of China Environment of Mongolia