Variations of widespread extreme cold and warm days in winter over China and their possible causes

Abstract The two leading modes of winter surface air temperature (SAT) over China during 1961–2017 are a spatially consistent pattern and north-south dipole pattern. Based on the modes, characteristics extreme cold warm days in patterns, defined by standard deviation larger than 1.28 or smaller −1.28 time series analyzed. With increase SAT 1961–2017, number decreased their occurrence was restricted to late December early January, whereas increased significantly January February. Global warming is associated with an decrease days, but has little relation sum either Siberian High (SH) main factor controlling days. strong (weak) SH before (after) 1990s corresponds (decrease) occurrences south-cold-north-warm south-warm-north-cold related difference SH. When center mid-high latitudes, (south-cold-north-warm) occur more (less) often. During winters total changes negligibly. North Atlantic meridional overturning circulation (AMOC) may be affecting types China.