Advances in Climate Change Research (Jun 2021)
Identification of winter long-lasting regional extreme low-temperature events in Eurasia and their variation during 1948–2017
Abstract
Compared with short-duration events, long-lasting regional extreme low-temperature events (RELTEs) often have more severe impacts on human societies due to the induced persistence and large geographic area of related weather and climate disaster. Accordingly, an improved objective technique was applied to identify all long-lasting RELTEs in Eurasia from the winter of 1948/1949 to 2017/2018, followed by an in-depth discussion of its variation in terms of the annual frequency, duration, impacted area, mean intensity, maximum intensity, and a comprehensive index. The RELTE lasting for 52 d in the winter of 2007/2008 exhibited the longest duration, largest impacted area, and a greatest comprehensive index, which induced extremely low temperatures for more than 20 d in Western Asia, Central Asia, and China. During the past 70 winters, the frequency of long-lasting RELTEs decreased, especially after the late 1960s. Nevertheless, the mean and maximum intensities and comprehensive index exhibited distinctly increasing trends. All indicators of winter long-lasting RELTEs had a similar inter-decadal fluctuation featured by two noticeable peaks occurring around 1970 and 2007, and a remarkable recovery was discovered in the period of late 1990s to mid-2010s, especially for the occurrence of super long-lasting events. Significantly, winter long-lasting RELTEs in Eurasia showed distinct trends under various decadal climate backgrounds, i.e., a strong negative or weak positive trend in the accelerated warming period and conversely, a strong positive or weak negative trend in the warming slowdown stage. These findings indicate that we should be alert of the similar future recovery of winter long-lasting RELTEs in Eurasia, which are likely to occur in the slowdown period of global warming.
