共同研究報告書


研究区分 一般研究

研究課題

 dynamics of the water exchange between the ice shelf cavity and the open ocean
新規・継続の別 新規
研究代表者／所属 東北大学
研究代表者／職名 特任研究員
研究代表者／氏名 原楠

研究分担者／氏名／所属／職名
　
氏　　名
所　　属
職　　名

1

 Sayaka Yasunaka 東北大学 教授

2

 原楠 東北大学 特任研究員

3

 Tomohiro Nakamura 北大低温研 講師

4

 Humio Mitsudera 北大低温研 名誉教授

研究目的 Water exchange between ice-shelf cavities and the open ocean plays a critical role in regulating basal melting and sea-level rise in West Antarctica， yet the underlying small-scale dynamics remain poorly understood， specifically the water exchange process around the ice draft. This study investigates an O (1 km) exchange process at the ice front， in which a barotropic water column intrudes directly into an ice-shelf cavity. We study the process from the perspectives of the numerical simulation and the dynamical theory.
Fig.1: water column along a stream function with an ice front on the west side　Fig. 2: water column along a stream function with a west wall　
研究内容・成果 We simulate this process using an idealized barotropic， inviscid model. The results show that the flow undergoes pronounced vertical twisting upstream of the ice front. A western-boundary-current-like jet forms adjacent to the ice front， while the lower portion of the water column becomes vertically compressed and is able to intrude into the cavity beneath the ice draft. Consequently， the flow locally departs from the Taylor column structure.
The simulations further reveal strong negative relative vorticity upstream of the ice front and strong positive relative vorticity downstream. The generation of these vorticity anomalies can be explained by barotropic potential vorticity conservation associated with changes in water-column thickness. The resulting relative vorticity becomes locally comparable to the planetary vorticity， producing a Rossby number of order unity and thereby allowing the Taylor column to break down.
These results highlight the role of inertial adjustment and the geometric constraint imposed by the ice draft in enabling cross-front exchange (Figs. 1 and 2). More broadly， this study provides new insight into classical inertial boundary-current theory and its application to flows interacting with ice-shelf fronts.
Fig.1: water column along a stream function with an ice front on the west side　Fig. 2: water column along a stream function with a west wall　
成果となる論文・学会発表等 Nan Yuan， Humio Mitsudera， Sayaka Yasunaka， Barotropic water exchange between the ice cavity and the open ocean in a non-friction fluid， Poster， OSM， Glasgow， Scotland， England 2026.02.25;
Nan Yuan， Humio Mitsudera， Sayaka Yasunaka， Barotropic water exchange between the ice cavity and the open ocean， Oral， Mombetsu symposium， Hokkaido， Japan 2026.02.17;
Nan Yuan， Humio Mitsudera， Sayaka Yasunaka， Tomohiro Nakamura， Barotropic water exchange between the ice cavity and the open ocean in an inviscid fluid， collaborative project seminar， Hokkaido University， Sapporo， Japan， 2025.12.23