West-warming East-cooling trend over Antarctica reversed since early 21st century driven by large-scale circulation variation

• Published in: Environmental Research Letters
• Main Authors: Meijiao Xin, Kyle R Clem, John Turner, Sharon E Stammerjohn, Jiang Zhu, Wenju Cai, Xichen Li
• Format: Article in Journal/Newspaper
• Language: English
• Published: IOP Publishing 2023
• Subjects: Antarctic rapid warming; seesaw temperature pattern; thermal advection; Environmental technology. Sanitary engineering; TD1-1066; Environmental sciences; GE1-350; Science; Q; Physics; QC1-999; Antarctic; Antarctic Peninsula; Austral; East Antarctica; Pacific; The Antarctic; Weddell; Weddell Sea; West Antarctica; Antarc*; Antarctica; Sea ice
• Online Access: https://doi.org/10.1088/1748-9326/acd8d4; https://doaj.org/article/3a2a3335906640ff9758873dab28ed00

Antarctic climate changes prior to 2000 were characterized by a strong zonally asymmetric pattern. Over 90% of the land ice mass loss occurred around a limited area in West Antarctica, accompanied by a rapid surface warming rate about three times the global mean. In contrast, surface warming and glacier mass loss around East Antarctica are not significant, until the decades since 2000 when several individual stations show that the temperature trends might have reversed. The asymmetric climate changes between East- and West-Antarctica are largely attributable to the inter-decadal variabilities over the Pacific and Atlantic Oceans through tropical–polar teleconnections, leaving open the question of whether the post-2000 phase shift of the lower-latitude decadal variability causes a flip of the asymmetric Antarctic changes. Here, by synthesizing 26 in-situ observations and 6 reanalysis datasets using a statistical method and integrating the results with a series of climate model experiments, we find that the West-warming, East-cooling trend over Antarctica has systematically reversed in austral spring since the early 21 ^st century, largely due to the atmospheric circulation anomaly over the Antarctic Peninsula–Weddell Sea region, which is associated to the teleconnection with Pacific and atmospheric internal variability. This reversal of the temperature seesaw suggests that substantial decadal-scale fluctuations of the Antarctic climate system exist, including for sea-ice and land-ice systems, superimposed on and modifying longer term changes.