Abstract
Comment
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Oral or Poster
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IAMAS
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JCMP08 - Connecting Polar to lower latitudes: A global perspective on climate change and impacts for Future Earth Strategies
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Strong impact of the rare three-year La Nina event on Antarctic surface climate changes in 2021?2023
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1. Shaoyin Wang*, School of Geospatial Engineering and Science,Sun Yat-sen University,and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai),Zhuhai,China
2. Jiping Liu, School of Atmospheric Science,Sun Yat-sen University,and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai),Zhuhai,China
3. Wenju Cai, Frontiers Science Center for Deep Ocean Multispheres and Earth System (FDOMES) and Key Laboratory of Physical Oceanography,Ocean University of China,Qingdao,China
4. Dongxia Yang, Analycia Pty. Ltd,Melbourne,VIC,Australia
5. Tobias Kerzenmacher, Karlsruhe Institute of Technology (KIT),Institute of Meteorology and Climate Research Atmospheric Trace Gases and Remote Sensing (IMK-ASF),Karlsruhe,Germany
6. Suoyi Ding, Department of Atmospheric and Oceanic Sciences,Fudan University,Shanghai
7. Xiao Cheng, China
8. *, School of Geospatial Engineering and Science,Sun Yat-sen University,and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai),Zhuhai,China
*Presenting Author
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From 2021 to 2023, satellite records reveal that February Antarctic sea ice extent reached record lows in 2022 and 2023. Simultaneously, the Antarctic ice sheet experienced a transient mass gain and rebounded temporarily from a decadal decline since 2002. The reasons behind these dramatic changes are unknown. Here, we show that the triple-dip La Ni?a event during 2021?2023 (referred to as TD_LN2023) was a major driver of these changes. Compared to a previous triple-dip La Ni?a event (1999?2001), the tropical-Antarctic teleconnections during TD_LN2023 were stronger. A more pronounced southward shift of the Ferrel Cell was identified as a key driver for the enhanced tropical-Antarctic teleconnections during TD_LN2023, facilitating poleward atmospheric heat and moisture transport. The poleward increase contributed to the sea ice extent decline and the ice sheet mass growth. Additionally, this southward shift strengthened the Rossby wave train, which, sustained by enhanced stratosphere-troposphere coupling, amplified the Pacific-South American pattern, and further promoted regional sea ice decline. Finally, this southward shift, associated with the southward shift of the westerly jet, enhanced Ekman suction, bringing subsurface warm water to the surface and contributing to pan-Antarctic low sea ice. The physical processes outlined in the case study are further validated through empirical orthogonal function and regression analysis. Under global warming, multi-year La Ni?a events are projected to occur more frequently. The evolving tropical-Antarctic teleconnections in the context warrant close attention.