日本地球惑星科学連合2019年大会

講演情報

[J] ポスター発表

セッション記号 A (大気水圏科学) » A-CG 大気海洋・環境科学複合領域・一般

[A-CG37] 北極域の科学

2019年5月30日(木) 17:15 〜 18:30 ポスター会場 (幕張メッセ国際展示場 8ホール)

コンビーナ:漢那 直也(北海道大学北極域研究センター)、庭野 匡思(気象研究所)、中村 哲(北海道大学大学院地球環境科学研究院)、鄭 峻介(北海道大学 北極域研究センター)

[ACG37-P15] A large-eddy simulation of upwelling meltwater plume at marine-terminating glacier fronts

*松村 義正1漢那 直也2杉山 慎3,2 (1.東京大学 大気海洋研究所、2.北海道大学 北極域研究センター、3.北海道大学 低温科学研究所)

キーワード:氷河融解水プルーム、large-eddy simulation

To investigate the behavior of subglacier discharge of meltwater and its impact on the oceanic environment in Greenland fjords, large-eddy simulations of upwelling meltwater plume were performed using a three-dimensional non-hydrostatic ocean model.

The model setup was idealized based on in-situ measurements at the glacier front in the Bowdoin fjold, northwestern Greenland. The model resolution was 2.0 m horizontally and vertically and the time step interval was less than 0.1 second, which were sufficiently fine to capture the turbulent nature of upwelling plume and its high frequency disturbance recorded in the in-situ data.

The buoyancy supply caused by the underwater discharge of fresh meltwater induced immediate and strong upwelling, then the plume reached the surface with vertical momentum that radially pushed out the surface water and clearly formed semicircular structure of ~200 m adjoined to the glacier front, which was visualized by high turbidity in reality.
Since the turbulent plume entrains the saline and nutrient-rich water of Atlantic origin below thermocline, the underwater meltwater discharge acts as a pump for providing nutrients to the photic layer, that may support primary production and ecosystem in the fjold.

In the presentation, we will introduce results of sensitivity experiments with different shapes of glacier front cavity and discharge conduit, and quantitative comparison with in-situ observations will be discussed.