Diapycnal mixing variations induced by subthermocline eddies observed in the north Pacific western boundary region
Recent observations prove that subthermocline eddies (SEs) are energetic in the north Pacific western boundary region, where interhemispheric waters meet. Our previous study showed that the SEs play an important role in isopycnal mixing of interhemispheric intermediate waters. Whether the SEs can in...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Frontiers Media S.A.
2022-10-01
|
| Series: | Frontiers in Marine Science |
| Subjects: | |
| Online Access: | https://www.frontiersin.org/articles/10.3389/fmars.2022.997599/full |
| _version_ | 1817978185675964416 |
|---|---|
| author | Feng Nan Feng Nan Feng Nan Feng Nan Feng Nan Huijie Xue Huijie Xue Fei Yu Fei Yu Fei Yu Fei Yu Qiang Ren Qiang Ren Qiang Ren Jianfeng Wang Jianfeng Wang Jianfeng Wang |
| author_facet | Feng Nan Feng Nan Feng Nan Feng Nan Feng Nan Huijie Xue Huijie Xue Fei Yu Fei Yu Fei Yu Fei Yu Qiang Ren Qiang Ren Qiang Ren Jianfeng Wang Jianfeng Wang Jianfeng Wang |
| author_sort | Feng Nan |
| collection | DOAJ |
| description | Recent observations prove that subthermocline eddies (SEs) are energetic in the north Pacific western boundary region, where interhemispheric waters meet. Our previous study showed that the SEs play an important role in isopycnal mixing of interhemispheric intermediate waters. Whether the SEs can induce diapycnal mixing in the western boundary region is unknown although it has been found true in the interior region. In this study, based on in-situ observations and fine-scale parameterization method, we show spatial structure and variability of diapycnal mixing induced by the SEs in the north Pacific western boundary region. The SEs are located between 200 and 750 m with a maximum swirl speed reaching 0.5 m s-1 and exhibit significant intra-seasonal variability with the period ranging between 50 and 100 days. Compared with shears induced by tides and near-inertial oscillation, sub-inertial shears induced by the SEs are dominant in the subthermocline layer. Consequently, diapycnal diffusivity is elevated up to O(10-4) m2 s-1 about one order higher than the background value when the SEs were passing by. The integrated diapycnal diffusivity between 200 and 750 m is increased by 210%. Modulated by the SEs, diapycnal mixing in the subthermocline has significant intra-seasonal variations. With more and more SEs being observed around the global oceans, we suggest that SE-induced mixing may not be trivial in closing the global ocean energy budget. |
| first_indexed | 2024-04-13T22:25:56Z |
| format | Article |
| id | doaj.art-7d3bfb820dec40df9de92bbb201e1c44 |
| institution | Directory Open Access Journal |
| issn | 2296-7745 |
| language | English |
| last_indexed | 2024-04-13T22:25:56Z |
| publishDate | 2022-10-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Marine Science |
| spelling | doaj.art-7d3bfb820dec40df9de92bbb201e1c442022-12-22T02:27:04ZengFrontiers Media S.A.Frontiers in Marine Science2296-77452022-10-01910.3389/fmars.2022.997599997599Diapycnal mixing variations induced by subthermocline eddies observed in the north Pacific western boundary regionFeng Nan0Feng Nan1Feng Nan2Feng Nan3Feng Nan4Huijie Xue5Huijie Xue6Fei Yu7Fei Yu8Fei Yu9Fei Yu10Qiang Ren11Qiang Ren12Qiang Ren13Jianfeng Wang14Jianfeng Wang15Jianfeng Wang16Key Laboratory of Ocean Circulation and Wave Studies, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, ChinaCenter for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, ChinaPilot National Laboratory for Marine Science and Technology, Qingdao, ChinaCollege of Earth Science, University of Chinese Academy of Sciences, Beijing, ChinaState Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, ChinaState Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, ChinaDepartment of Physical Oceanography, College of Ocean and Earth Sciences, Xiamen University, Xiamen, ChinaKey Laboratory of Ocean Circulation and Wave Studies, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, ChinaCenter for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, ChinaPilot National Laboratory for Marine Science and Technology, Qingdao, ChinaCollege of Earth Science, University of Chinese Academy of Sciences, Beijing, ChinaKey Laboratory of Ocean Circulation and Wave Studies, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, ChinaCenter for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, ChinaPilot National Laboratory for Marine Science and Technology, Qingdao, ChinaKey Laboratory of Ocean Circulation and Wave Studies, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, ChinaCenter for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, ChinaPilot National Laboratory for Marine Science and Technology, Qingdao, ChinaRecent observations prove that subthermocline eddies (SEs) are energetic in the north Pacific western boundary region, where interhemispheric waters meet. Our previous study showed that the SEs play an important role in isopycnal mixing of interhemispheric intermediate waters. Whether the SEs can induce diapycnal mixing in the western boundary region is unknown although it has been found true in the interior region. In this study, based on in-situ observations and fine-scale parameterization method, we show spatial structure and variability of diapycnal mixing induced by the SEs in the north Pacific western boundary region. The SEs are located between 200 and 750 m with a maximum swirl speed reaching 0.5 m s-1 and exhibit significant intra-seasonal variability with the period ranging between 50 and 100 days. Compared with shears induced by tides and near-inertial oscillation, sub-inertial shears induced by the SEs are dominant in the subthermocline layer. Consequently, diapycnal diffusivity is elevated up to O(10-4) m2 s-1 about one order higher than the background value when the SEs were passing by. The integrated diapycnal diffusivity between 200 and 750 m is increased by 210%. Modulated by the SEs, diapycnal mixing in the subthermocline has significant intra-seasonal variations. With more and more SEs being observed around the global oceans, we suggest that SE-induced mixing may not be trivial in closing the global ocean energy budget.https://www.frontiersin.org/articles/10.3389/fmars.2022.997599/fullsubthermocline eddyturbulent mixingshearwestern boundary regionmicrostructure observations |
| spellingShingle | Feng Nan Feng Nan Feng Nan Feng Nan Feng Nan Huijie Xue Huijie Xue Fei Yu Fei Yu Fei Yu Fei Yu Qiang Ren Qiang Ren Qiang Ren Jianfeng Wang Jianfeng Wang Jianfeng Wang Diapycnal mixing variations induced by subthermocline eddies observed in the north Pacific western boundary region Frontiers in Marine Science subthermocline eddy turbulent mixing shear western boundary region microstructure observations |
| title | Diapycnal mixing variations induced by subthermocline eddies observed in the north Pacific western boundary region |
| title_full | Diapycnal mixing variations induced by subthermocline eddies observed in the north Pacific western boundary region |
| title_fullStr | Diapycnal mixing variations induced by subthermocline eddies observed in the north Pacific western boundary region |
| title_full_unstemmed | Diapycnal mixing variations induced by subthermocline eddies observed in the north Pacific western boundary region |
| title_short | Diapycnal mixing variations induced by subthermocline eddies observed in the north Pacific western boundary region |
| title_sort | diapycnal mixing variations induced by subthermocline eddies observed in the north pacific western boundary region |
| topic | subthermocline eddy turbulent mixing shear western boundary region microstructure observations |
| url | https://www.frontiersin.org/articles/10.3389/fmars.2022.997599/full |
| work_keys_str_mv | AT fengnan diapycnalmixingvariationsinducedbysubthermoclineeddiesobservedinthenorthpacificwesternboundaryregion AT fengnan diapycnalmixingvariationsinducedbysubthermoclineeddiesobservedinthenorthpacificwesternboundaryregion AT fengnan diapycnalmixingvariationsinducedbysubthermoclineeddiesobservedinthenorthpacificwesternboundaryregion AT fengnan diapycnalmixingvariationsinducedbysubthermoclineeddiesobservedinthenorthpacificwesternboundaryregion AT fengnan diapycnalmixingvariationsinducedbysubthermoclineeddiesobservedinthenorthpacificwesternboundaryregion AT huijiexue diapycnalmixingvariationsinducedbysubthermoclineeddiesobservedinthenorthpacificwesternboundaryregion AT huijiexue diapycnalmixingvariationsinducedbysubthermoclineeddiesobservedinthenorthpacificwesternboundaryregion AT feiyu diapycnalmixingvariationsinducedbysubthermoclineeddiesobservedinthenorthpacificwesternboundaryregion AT feiyu diapycnalmixingvariationsinducedbysubthermoclineeddiesobservedinthenorthpacificwesternboundaryregion AT feiyu diapycnalmixingvariationsinducedbysubthermoclineeddiesobservedinthenorthpacificwesternboundaryregion AT feiyu diapycnalmixingvariationsinducedbysubthermoclineeddiesobservedinthenorthpacificwesternboundaryregion AT qiangren diapycnalmixingvariationsinducedbysubthermoclineeddiesobservedinthenorthpacificwesternboundaryregion AT qiangren diapycnalmixingvariationsinducedbysubthermoclineeddiesobservedinthenorthpacificwesternboundaryregion AT qiangren diapycnalmixingvariationsinducedbysubthermoclineeddiesobservedinthenorthpacificwesternboundaryregion AT jianfengwang diapycnalmixingvariationsinducedbysubthermoclineeddiesobservedinthenorthpacificwesternboundaryregion AT jianfengwang diapycnalmixingvariationsinducedbysubthermoclineeddiesobservedinthenorthpacificwesternboundaryregion AT jianfengwang diapycnalmixingvariationsinducedbysubthermoclineeddiesobservedinthenorthpacificwesternboundaryregion |