Winter Temperature over East Asia and Atmospheric Circulation Patterns in the Last 100 Years
近百年东亚冬季气温及其大气环流变化型态

Two patterns of winter temperature variability over East Asia and their association with the atmospheric circulation patterns for the last 100 years are documented based on the 20th century reanalysis datasets. In one pattern, the changes in temperature over the southwest of East Asia (south of 40°N and west of 105°E) are opposite to those over northeastern East Asia (north of 40°N and east of 105°E). The other pattern is characterized by consistent changes in temperature over East Asia south of 40°N. The Eurasian atmospheric circulation teleconnection pattern, the North Atlantic Oscillation (NAO), and the Siberian high are associated with the first type of East Asian temperature variability. The Eurasian pattern in a negative phase at 500 hPa, the NAO in a positive phase, and a weaker Siberian high are favorable for an increase in winter temperature over Mongolia and east of 105°E in China (Southwest China and the Tibetan Plateau), and vice versa. The western Pacific pattern (WP) at 500 hPa and the North Pacific Oscillation (NPO) correspond to the second type of East Asian temperature variability pattern. When WP and NPO were in a positive phase (negative values in the north and positive values in the south of the Pacific Ocean), the winter temperatures over the area south of 40°N in East Asia increased (decreased). The differences in the spatial pattern of the atmospheric modes can impact on the winter East Asian temperature interannual variability. During the last 100 years, the Eurasian pattern and the NAO were most notable during 1984-2010, contributing to the rapid warming over East Asia after the 1980s. We also found that the correlation between the East Asian winter temperature variability and polar circulation has increased since the middle of the 20th century and that the eastward extending Siberian high has a strong link to the polar circulation, which could also be responsible for the warming over East Asia during the last 100 years.