Australia: The Land Where Time Began

A biography of the Australian continent 

Arctic Warming – 2 Distinct Influences on Cold Winters Above North America and East Asia

There has been increasing warming in the Arctic because of possible mid-latitude climatic impacts (Francis & Vavrus, 2015; Wallace et al., 2014; Outten & Esau, 2012; Screen & Simmonds, 2014; Cohen et al., 2014). In many parts of East Asia and North America there have been a number of unusually harsh winters over the past few years (Wallace et al., 2014; Van Oldenborgh et al., 2015;  Wang & Chen, 2014), and it has been suggested by studies, both observational and modelling, that atmospheric variability is linked to warming in the Arctic, playing a central role (Francis & Vavrus, 2015; Outten & Esau, 2012; Screen & Simmonds, 2014; Kim et al., 2014; Honda, Inoue & Yamane, 2009). In this study Kug et al. identify 2 distinct influences of Arctic warming which may result in colder winters over East Asia and North America, which are based on the results of observational analyses and extensive climate modelling. They found that across East Asia there was an association between anomalous warmth in the Barents-Kara Sea region and severe winters, whereas anomalous warmth in the East Siberian-Chukchi Sea region is associated with severe winters over North America. Over the Arctic Ocean each regional warming is accompanied locally by the development of an anomalous anticyclone, and the development of a mid-latitude trough downstream. The northerly cold air flow that results provides favourable conditions for severe winters in East Asia and North America. Idealised climate model experiments and CMIP5 multi-model simulations also display robustly these links between Arctic and mid-latitude weather. Kug et al. suggest their results may help to improve seasonal winter weather and extreme events predictions in these regions.

Sources & Further reading

Kug, J.-S., J.-H. Jeong, Y.-S. Jang, B.-M. Kim, C. K. Folland, S.-K. Min and S.-W. Son (2015). "Two distinct influences of Arctic warming on cold winters over North America and East Asia." Nature Geosci 8(10): 759-762.