TY - JOUR
T1 - The Kuroshio flowing over seamounts and associated submesoscale flows drive 100-km-wide 100-1000-fold enhancement of turbulence
AU - Nagai, Takeyoshi
AU - Hasegawa, Daisuke
AU - Tsutsumi, Eisuke
AU - Nakamura, Hirohiko
AU - Nishina, Ayako
AU - Senjyu, Tomoharu
AU - Endoh, Takahiro
AU - Matsuno, Takeshi
AU - Inoue, Ryuichiro
AU - Tandon, Amit
N1 - Funding Information:
We are grateful for assistance by Captain Uchiyama, ℅ Azuma, crews of R/T/V Kagoshima maru, Professor Kobari (Kagoshima University), Professor Yoshie (Ehime University), and all the students participating in the cruise, including Kumagai, Rosales, Mori, Durán Gómez, Otero, Sakai, Karu, Kanayama, Kabe, Ogi, Yonemori, Honma, Zhang, Qiao, Lizarbe, and Chevarria. T.N. thanks OMIX (MEXT KAKENHI Grant Numbers: 18H04914, 16H01590), MEXT KAKENHI (19H01965), and SKED (JPMXD0511102330). T.N., H.D., R.I., E.T., H.N., T.S., T.E., and T.M. thank OMIX (MEXT KAKENHI Grant Numbers: 18H04914, 16H01590, 15H05818, 15H05821). A.T. thanks ONR (N0014-18-1-2799).
Funding Information:
We are grateful for assistance by Captain Uchiyama, ℅ Azuma, crews of R/T/V Kagoshima maru, Professor Kobari (Kagoshima University), Professor Yoshie (Ehime University), and all the students participating in the cruise, including Kumagai, Rosales, Mori, Durán Gómez, Otero, Sakai, Karu, Kanayama, Kabe, Ogi, Yonemori, Honma, Zhang, Qiao, Lizarbe, and Chevarria. T.N. thanks OMIX (MEXT KAKENHI Grant Numbers: 18H04914, 16H01590), MEXT KAKENHI (19H01965), and SKED (JPMXD0511102330). T.N., H.D., R.I., E.T., H.N., T.S., T.E., and T.M. thank OMIX (MEXT KAKENHI Grant Numbers: 18H04914, 16H01590, 15H05818, 15H05821). A.T. thanks ONR (N0014-18-1-2799).
Publisher Copyright:
© 2021, The Author(s).
PY - 2021/12
Y1 - 2021/12
N2 - 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.
AB - 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.
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U2 - 10.1038/s43247-021-00230-7
DO - 10.1038/s43247-021-00230-7
M3 - Article
AN - SCOPUS:85120536257
SN - 2662-4435
VL - 2
JO - Communications Earth and Environment
JF - Communications Earth and Environment
IS - 1
M1 - 170
ER -