JpGU-AGU Joint Meeting 2020

Presentation information

[E] Poster

M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS15] Global climate change driven by the Southern Ocean and the Antarctic Ice Sheet

convener:Osamu Seki(Institute of Low Temperature Science, Hokkaido University), Akira Oka(Atmosphere and Ocean Research Institute, The University of Tokyo), Yoshifumi Nogi(National Institute of Polar Research), Robin Elizabeth Bell(Lamont Doherty Earth Observatory)

[MIS15-P28] Changes in oxygen and CFC concentrations in AABW along 115°E from 1990s to 2010s

*Michiyo Yamamoto-Kawai1, Narimi Baba1, Yoshihiko Ohashi1 (1.Graduate School of Marine Science and Technology, Tokyo University of Marine Science and Technology)

Keywords:AABW, CFC, Oxygen

Antarctic Bottom Water (AABW) is formed by a mixing of old deep water with newerly ventilated shelf water. This process has important implications for the transport of heat, freshwater, oxygen and carbon into deep ocean. Recent studies suggest reduction of AABW formation due to surface warming and freshening. In order to investigate changes in ventilation rate and properties of AABW, we have compared CFCs, oxygen and other water properties between observations made in 2016/2017 and 1995/1996 in the Australian sector of the Southern Ocean. Results showed increases in apparent oxygen utilization (AOU) and CFC age, indicating reduced ventilation of AABW in 20 years. We compare results with model simulation to discuss possible mechanisms of the reduction as well as quantitative implication of the reduction.