Upper ocean mixing plays a key role in the atmosphere-ocean heat transfer and sea ice extent and thickness via modulating the upper ocean temperatures in the Arctic Ocean. Observations of diffusivities in the Arctic that directly indicate the ocean mixing properties are sparse. Therefore, the spatiotemporal pattern and magnitude of diapycnal diffusivities and kinetic energy dissipation rates in the upper Arctic Ocean are important for atmosphere-ocean heat transfers and sea ice changes. These were first estimated from the Ice-Tethered Profilers dataset (2005–2019) using a strain-based fine-scale parameterization. The resultant mixing properties showed significant geographical inhomogeneity and temporal variability. Diapycnal diffusivities and dissipation rates in the Atlantic sector of the Arctic Ocean were stronger than those on the Pacific side. Mixing in the Atlantic sector increased significantly during the observation period; whereas in the Pacific sector, it weakened before 2011 and then strengthened. Potential impact factors include wind, sea ice, near inertial waves, and stratification, while their relative contributions vary between the two sectors of the Arctic Ocean. In the Atlantic sector, turbulent mixing dominated, while in the Pacific sector, turbulent mixing was inhibited by strong stratification prior to 2011, and is able to overcome the stratification gradually after 2014. The vertical turbulent heat flux constantly increased in the Atlantic sector year by year, while it decreased in the Pacific sector post 2010. The estimated heat flux variability induced by enhanced turbulent mixing is expected to continue to diminish sea ice in the near future.

Jia YOU;Zhenhua XU;Robin ROBERTSON;Qun LI;Baoshu YIN

CAS Key Laboratory of Ocean Circulation and Waves,Institute of Oceanology,Chinese Academy of Sciences,Qingdao 266071,China;Pilot National Laboratory for Marine Science and Technology(Qingdao),Qingdao 266237,China;Center for Ocean Mega-Science,Chinese Academy of Sciences,Qingdao 266071,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China;CAS Engineering Laboratory for Marine Ranching,Institute of Oceanology,Chinese Academy of Sciences,Qingdao 266071,China;China-Asean College of Marine Science,Xiamen University Malaysia,Sepang 43900,Malaysia;MNR Key Laboratory for Polar Science,Polar Research Institute of China,Shanghai 200120,China

海洋湖沼学报（英文版）

[1]Jia YOU;Zhenhua XU;Robin ROBERTSON;Qun LI;Baoshu YIN-.Geographical inhomogeneity and temporal variability of mixing property and driving mechanism in the Arctic Ocean)[J].海洋湖沼学报（英文版）,2022(03):846-869

Tethered,Profilers,Diapycnal

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