Japan Geoscience Union Meeting 2024

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[J] Oral

M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS10] Global climate change driven by the Southern Ocean and the Antarctic Ice Sheet

Fri. May 31, 2024 10:45 AM - 12:00 PM 105 (International Conference Hall, Makuhari Messe)

convener:Kazuya Kusahara(Japan Agency for Marine-Earth Science and Technology), Takeshige Ishiwa(National Institute of Polar Research), Ikumi Oyabu(National Institute of Polar Research, Research Organization of Information and Systems), Osamu Seki(Institute of Low Temperature Science, Hokkaido University), Chairperson:Kazuya Kusahara(Japan Agency for Marine-Earth Science and Technology), Takeshige Ishiwa(National Institute of Polar Research), Ikumi Oyabu(National Institute of Polar Research, Research Organization of Information and Systems), Osamu Seki(Institute of Low Temperature Science, Hokkaido University)


11:00 AM - 11:15 AM

[MIS10-08] Synoptic Moisture Intrusion Provided Heavy Isotope Precipitations in Inland Antarctica during the Last Glacial Maximum

*Kanon Kino1, Alexandre CAUQUOIN2, Atsushi Okazaki3, Taikan Oki1, Kei Yoshimura2 (1.Graduate School of Engineering, The University of Tokyo, 2.Institute of Industrial Science, The University of Tokyo, 3.Institute for Advanced Academic Research, Chiba University)

Keywords:paleoclimate, ice core, Antarctica, climate model, Water isotope

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.

K. Kino, A. Cauquoin, A. Okazaki, T. Oki, K. Yoshimura, Synoptic Moisture Intrusion Provided Heavy Isotope Precipitations in Inland Antarctica during the Last Glacial Maximum, Geophys. Res. Let. (Under revision). https://essopenarchive.org/doi/full/10.22541/essoar.170689105.5446982