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

Understanding human influence on climate change in China

“…Heavy snowfall as an important form of heavy precipitation has shown an increase in parts of northern China in the recent decade [ 105 ]. These changes seem to be linked to changes in atmospheric circulation [ 106 ], but the causes of the circulation change are unclear.…”

Synergistic impacts of westerlies and monsoon on interdecadal variations of late spring precipitation over the southeastern extension of the Tibetan Plateau

“…Under such circumstances, AMO may play a significant modulatory role in WMI. Further analyses revealed that the predominant anomalies of divergence and RWS in the upper troposphere can be triggered by the AMO (Figure 15a), according to theoretical and applied research concerning RWS (e.g., Sardeshmukh and Hoskins, 1988; Guo et al ., 2019; Miao and Jiang, 2021; Zhou et al ., 2021), in which the advection of vorticity by divergent wind acts as the R , causing far‐reaching Eurasian climate anomalies. Therefore, a distinct AMO‐induced, planetary‐scale zonal Rossby wave train can be forced east of the North Atlantic with alternating cyclonic and anticyclonic anomalies (Figure 15b), propagating eastward, thus transmitting the influence of remote interdecadal North Atlantic SST warming into the downstream regions through far‐reaching zonal teleconnection.…”

“…Additionally, similar AMO‐related regional‐scale patterns of the mid‐level anticyclonic anomaly over the western TP (Figure 18a) and low‐level cyclonic wind shear anomaly (negative height anomalies) (Figure 18b) could also be simulated satisfactorily, although these simulated patterns shifted more southward (~10°N) and westward (~20°E), respectively. Note that these modelled AMO‐related patterns with obvious position biases are a common phenomenon documented in other AMO model simulations (e.g., Wu et al ., 2019; Zhou et al ., 2021). By comparing Figures 15b and 17, it should be noted that the energy sources of the Rossby wave are slightly different between the observation and modelling experiments.…”

Changes of Atlantic Multidecadal Variability During the Medieval Climate Anomaly and Little Ice Age and Associated Causes

“…For instance, it is indicated that the cold phase of the AMV plays a part in the global warming hiatus during 1998–2012 (Mann et al., 2014; Medhaug et al., 2017; Steinman et al., 2015). Warm phases of the AMV coincide with more Sahel summer rainfall (Ting et al., 2011; Zhang & Delworth, 2006), wetter summers in northern Europe (Ruprich‐Robert et al., 2017; Sutton & Dong, 2012), more summer heat wave days over the southern United States (Ruprich‐Robert et al., 2018), and colder winters over the mid‐latitude Eurasian continent (Miao & Jiang, 2021, 2022; B. Zhou et al., 2021). Considering the importance of the AMV, many studies have investigated its characteristics and drivers (Vecchi et al., 2017).…”