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Synoptic Moisture Intrusion Provided Heavy Isotope Precipitations in Inland Antarctica during the Last Glacial Maximum
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  • Kanon Kino,
  • Alexandre Cauquoin,
  • Atsushi Okazaki,
  • Taikan Oki,
  • Kei Yoshimura
Kanon Kino
The University of Tokyo

Corresponding Author:[email protected]

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Alexandre Cauquoin
Institute of Industrial Science, The University of Tokyo
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Atsushi Okazaki
Chiba University, Hirosaki University
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Taikan Oki
University of Tokyo
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Kei Yoshimura
Institute of Industrial Science, The University of Tokyo
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Stable water isotopes in inland Antarctic ice cores are powerful paleoclimate proxies; however, their relationship with dynamical atmospheric circulations remains controversial. Using a water isotope climate model (MIROC5-iso), we assessed the influence of the Last Glacial Maximum (LGM; ~21,000 years ago) sea surface temperatures (SST) and sea ice (SIC) on Antarctic precipitation isotopes (δ18Op) through atmospheric circulation. The results revealed that the synoptic circulation mostly maintained southward moisture transport, reaching inland Antarctica. The steepened meridional SST gradient in the mid-latitudes increased δ18Op in inland Antarctica by enhancing the baroclinic instability and synoptic moisture transport. In contrast, enhanced SIC reduced the atmospheric humidity around Antarctica and lowered δ18Op through extensive surface cooling and transport from the ocean. These findings elucidate the isotopic proxies and enable us to constrain the southern hemisphere atmospheric circulation, including the westerlies, using ice cores during past climates, including the LGM.
11 Jan 2024Submitted to ESS Open Archive
02 Feb 2024Published in ESS Open Archive