Strengthened impact of late autumn Arctic sea ice on Asian winter cold extremes after 1999/2000

• Published in: Environmental Research Letters
• Main Authors: Cen Wang, Hui Su, Jianqiu Zheng, Shiwei Yu, Linwei Jiang, Huisi Mo
• Format: Article in Journal/Newspaper
• Language: English
• Published: IOP Publishing 2024
• Subjects: Arctic sea ice; Asian winter cold extremes; long-term climate change; Environmental technology. Sanitary engineering; TD1-1066; Environmental sciences; GE1-350; Science; Q; Physics; QC1-999; Climate change; Sea ice
• Online Access: https://doi.org/10.1088/1748-9326/ad57d5; https://doaj.org/article/3e939301cf204a098615213159185ca7

Winter cold extremes (WCEs) frequently plague densely populated areas of Asia, leading to substantial economic losses and even fatalities. It has been found that the late autumn sea ice concentration (SIC) anomalies in the northern (SICN) and southern Arctic (SICS) are significantly positively and negatively correlated with the occurrence frequency of WCE in Asia, respectively (Wang and Su 2024). Our study demonstrates that the impacts of SICN and SICS have strengthened after 1999/2000. Specifically, before 1999/2000, the influences of SICN and SICS on the Asian WCE (AWCE) were relatively weak, possibly related to the weak intensity of SICS and the limited correlation between SICN and SICS. After 1999/2000, the interannual variability of SICS became larger and anti-correlated with that of SICN, resulting in a stronger teleconnection between the Arctic SIC and AWCE. It is revealed that after 1999/2000, the greater loss of SICS modified atmospheric stability through changes in surface heat fluxes and surface upward longwave radiation fluxes. This alteration weakened the magnitudes of westerly winds and increased the frequency of blocking events over the northern Eurasian continent, leading directly to a higher occurrence of cold extremes in Asia. These interdecadal differences in the influence of Arctic SIC on AWCE may be associated with long-term climate change.