The Kuroshio flowing over seamounts and associated submesoscale flows drive 100-km-wide 100-1000-fold enhancement of turbulence
| Autor: | Ayako Nishina, Daisuke Hasegawa, Takeyoshi Nagai, Tomoharu Senjyu, Amit Tandon, Takeshi Matsuno, Eisuke Tsutsumi, Hirohiko Nakamura, Takahiro Endoh, Ryuichiro Inoue |
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| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
沖縄トラフ・トカラ海峡で高鉛直波数近慣性波シアと乱流が卓越するメカニズム
geography 二台同時自由落下曳航観測手法を用いたマルチスケール混合現象とその影響に関する研究 QE1-996.5 geography.geographical_feature_category Resolving multi-scale mixing processes and their impacts using a twin tow-yo microstructure profiling system Turbulence Seamount Geology Fold (geology) Dissipation Vorticity 科学研究費研究成果 黒潮源流が陸棚縁で生成する近慣性内部波と躍層における鉛直混合メカニズムの解明 Atmospheric sciences Environmental sciences Orders of magnitude (time) Mechanisms of dominant vertical high wavenumber near inertial shear and strong turbulence in the Okinawa Trough and the Tokara Strait Negative potential General Earth and Planetary Sciences GE1-350 Near-inertial wave generations and diapycnal mixing in the Kuroshio origin regions near the continental shelf Mixing (physics) General Environmental Science |
| Zdroj: | Communications Earth & Environment, Vol 2, Iss 1, Pp 1-11 (2021) 研究代表者: 長井 健容 (東京海洋大学) |
| ISSN: | 2662-4435 |
| DOI: | 10.1038/s43247-021-00230-7 |
| Popis: | Although previous studies reported that currents over topographic features, such as seamounts and ridges, cause strong turbulence in close proximity, it has been elusive how far intense turbulence spreads toward the downstream. Here, we conducted a series of intensive in-situ turbulence observations using a state-of-the-art tow-yo microstructure profiler in the Kuroshio flowing over the seamounts of the Tokara Strait, south of Kyusyu Japan, in November 2017, June 2018, and November 2019, and employed a high-resolution numerical model to elucidate the turbulence generation mechanisms. We find that the Kuroshio flowing over seamounts generates streaks of negative potential vorticity and near-inertial waves. With these long-persisting mechanisms in addition to other near-field mixing processes, intense mixing hotspots are formed over a 100-km scale with the elevated energy dissipation by 100- to 1000-fold. The observed turbulence could supply nutrients to sunlit layers, promoting phytoplankton primary production and CO2 uptake. Persistent and intense mixing hotspots are generated where the Kuroshio flows over steep seamounts, with an increase in energy dissipation by two to three orders of magnitude, according to tow-yo microstructure measurements combined with numerical simulations. |
| Databáze: | OpenAIRE |
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