Anthropogenic Influence on the Eastern China 2016 Super Cold Surge
Introduction. A super cold surge during the winter of December 2015 to February 2016 was widely reported by Chinese media. This cold surge originated from the Siberian High and swept across the country on 21–25 January 2016, bringing very strong winds and a large and sudden fall in temperature. During the cold surge, air temperatures dropped more than 12°C over 18% of the country and by 6°C over more than 80% of the country. More than 95% of the country experienced frigid winter weather with minimum temperatures below 0°C (Jiang et al. 2016). Record-breaking minimum temperatures were reported at many observing stations, with temperature at −46.8°C observed in the Inner Mongolia autonomous region. The lives of more than one billion people were affected by this cold surge. Snowfall occurred in Guangzhou, the capital city in one of the southernmost provinces in China— the first ever snow event since the meteorological observing station was established. Extreme weather brought by the cold surge, such as heavy snowfall, freezing rain, and frost, caused significant impacts on transportation and electricity transmission systems, and on agriculture and human health (CMA 2017). One would naturally expect a reduction in cold extremes as a result of global warming. Nevertheless, some studies have suggested that Arctic amplification of warming and Arctic sea ice loss may have contributed to the so-called “warm Arctic–cold Eurasia” pattern over the past few decades (e.g., Cohen et al. 2014; Mori et al. 2014). It has therefore been speculated that continued Arctic sea ice loss would cause more cold extremes in the continental midlatitudes. This does not seem to be the case in the United States where very cold winters have become less likely due to global warming (Wolter et al. 2015; Trenary et al. 2016). In China, a few recent studies have shown that the decrease in the intensity and frequency of cold extremes can be attributed to human influence (Yin et al. 2016; Lu et al. 2016) although the attribution of cold surge events has not yet been resolved. Here we examine a related question with regard to long-term change in extreme cold surges, such as the 2015 winter cold surge in eastern China, and possible causes of the change.