Japan Geoscience Union Meeting 2022

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[E] Oral

M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS03] The Southern Ocean and the Antarctic Ice Sheet dynamics in past, present and future

Wed. May 25, 2022 3:30 PM - 5:00 PM 104 (International Conference Hall, Makuhari Messe)

convener:Kazuya Kusahara(Japan Agency for Marine-Earth Science and Technology), convener:Akira Oka(Atmosphere and Ocean Research Institute, The University of Tokyo), Yoshifumi Nogi(National Institute of Polar Research), convener:Shun Tsutaki(National Institute of Polar Research), Chairperson:Kazuya Kusahara(Japan Agency for Marine-Earth Science and Technology), Akira Oka(Atmosphere and Ocean Research Institute, The University of Tokyo), Yoshifumi Nogi(National Institute of Polar Research), Shun Tsutaki(National Institute of Polar Research)

3:45 PM - 4:00 PM

[MIS03-02] Warm surface waters increase Antarctic ice shelf melt and delay dense water formation

*Shigeru Aoki1, Tomoki Takahashi1, Kaihe Yamazaki1, Daisuke Hirano2, Kazuya Ono1, Kazuya Kusahara3, Takeshi Tamura2, Guy D. Williams4 (1.Hokkaido University, 2.National Institute of Polar Research, 3.JAMSTEC, 4.University of Tasmania)

Keywords:Southern Ocean, Ice Shelf, Antarctic Surface Water

Melting ice shelves around Antarctica control the massive input of freshwater into the ocean and play an intricate role in global heat redistribution. The Amery Ice Shelf (AIS) regulates wintertime sea-ice growth and dense shelf water formation. We investigated the role of warm Antarctic Surface Water (AASW) in AIS melting and its impact on dense shelf water. Here we show that the coastal ocean in summer 2016/17 was almost sea-ice free, leading to higher AASW temperatures. The glacial meltwater fraction in AASW was the highest in the previous record, hypothesised to be attributable to anomalous AIS melting. The excess heat and freshwater in early 2017 delayed the seasonal evolution of dense shelf water. Focused on ice shelf melting at depth, the importance and impacts of warming surface waters has been overlooked. In a warming climate, increased surface water heating will reduce sea-ice and potentially Antarctic Bottom Water formation.