[A-CG42] 北極域の科学

[ACG42-08] Effectiveness of wind-constrained sea-ice momentum on formation of sea-ice distribution and upper halocline of Arctic Ocean in climate model

*小野 純¹、小室 芳樹¹、建部 洋晶¹、木村 詞明² (1.国立研究開発法人海洋研究開発機構、2.東京大学大気海洋研究所)

キーワード：海氷、北極海、気候モデル、風応力

Initialization of sea ice and the upper halocline in the Arctic Ocean is crucial for sea-ice prediction, but their representation in climate models still remains biased. Here, using historical and four different simulations by a single climate model, we find that constraining the sea-ice momentum by surface wind stress contributes to a better representation of the sea-ice velocity, area, and concentration. Moreover, the wind-constrained sea-ice drift modifies the underlying ocean structure via ice-ocean stress, leading to an improved climatological halocline in the upper Canada Basin. This is because the excessive negative wind and ice-ocean stress curl represented in the climate model without the sea-ice momentum constraint is weakened when constraining the sea-ice momentum, alleviating the depression of the halocline associated with the Ekman dynamics process. From these results, the improvement of sea-ice and ocean states by constraining sea-ice momentum is expected to make sea-ice prediction more accurate.