[A-CG46] Science in the Arctic Region

[ACG46-01] Water modification in the Barents Sea in a high-resolution ice-ocean model

*Takao Kawasaki¹, Yoshiki Komuro², Jun Ono² (1.Atmosphere and Ocean Research Insitutute, the University of Tokyo, 2.Institute of Arctic Climate and Environment Research, Japan Agency for Marine-Earth Science and Technology)

Keywords:Barents Sea, Ocean modeling, Water formation

Barents Sea Water (BSW) inflows to the intermediate layer in the Arctic Ocean and has impacts on the sea ice and climate system in the Arctic region. A lack of understanding of the mechanisms of BSW formation and inflow processes causes the bias of temperature and salinity in the Arctic Ocean even in state-of-art climate models. The Barents Sea Water is formed by the modification of the Atlantic Water caused by the sea surface cooling and mixing with the surface Polar Water. The quantitative estimate of the formation of Barents Sea Water is conducted by an ocean model.
An ice-ocean general circulation model named COCO is utilized in this study. The horizontal grid size spatially varies by placing the poles of the general curvilinear horizontal coordinates close to the Barents Sea. The horizontal grid size is 2-8 km in the Barents Sea. The model is integrated from 1980 to 2020 under the 3-hourly sea surface condition dataset (JRA55-do). The nudging of sea surface salinity is not applied to represent freshening seawater in this model. The temperature, salinity, and their decreases in the Barents Sea are well reproduced in our model. Sea surface cooling is the dominant process in water modification in the southern Barents Sea. The cooled Atlantic Water gets buoyancy due to mixing with sea-ice melting water near the surface in the northern and northeastern Barents Sea. The decrease of the sea surface cooling in the southern Barents Sea and the warming of BSW inflowing the Arctic Ocean are simulated in the 2010s.