Decadal Change of Heavy Snowfall over Northern China in the Mid-1990s and Associated Background Circulations

Abstract Analyses of observation data from 1961 to 2014 by using the empirical orthogonal function (EOF) method indicate that primary mode (a monosign pattern) heavy snowfall over northern China in winter shows evident variations a negative polarity positive mid-1990s. Associated with this decadal change, southward displacement polar front jet stream and northward shift subtropical upper troposphere are apparent. Accordingly, height anomaly dominates region Lake Balkhash Baikal occupies midlatitudes North Pacific middle troposphere. Such anomalous patterns high correspond approximately East Asian monsoon (EAWM) may favor interaction cold air moist airflows China, which helps increase local snowfall. Further investigation Atlantic multidecadal oscillation (AMO) phase warm 1990s also play role, through its linkage above atmospheric circulations aid downstream propagation wave train emanates Ocean.