TY - JOUR
T1 - Effect of a current trapped by a continental slope on the pathway of a coastal current crossing Toyama Trough, Japan
AU - Igeta, Yosuke
AU - Kuga, Mizuki
AU - Yankovsky, Alexander
AU - Wagawa, Taku
AU - Fukudome, Ken ichi
AU - Kaneda, Atsushi
AU - Ikeda, Satoshi
AU - Tsuji, Toshihiro
AU - Hirose, Naoki
N1 - Funding Information:
The authors thank Dr. T. Senjyu, Dr. S. Nakada, and Dr. S. Kida for useful discussions. We would like to thank the anonymous reviewers for their valuable comments and suggestions to improve the paper. We are indebted to Gabrielle Ricche for editing the manuscript. This research was supported by the Research Project for Utilizing Advanced Technologies in Agriculture, Forestry, and Fisheries in Japan. This work was supported by JSPS KAKENHI Grant 19K06198. The tidal data, meteorological data, and GPV-MSM data were provided by the Japan Meteorological Agency and the Geographical Survey Institute. The figures were produced by the GFD-DENNOU software library, the Generic Mapping Tools (GMT) and gnuplot.
Publisher Copyright:
© 2021, The Oceanographic Society of Japan and Springer Nature Singapore Pte Ltd.
PY - 2021/8
Y1 - 2021/8
N2 - To clarify the Tsushima Warm Current (TWC) system around a downstream region of Noto Peninsula (NP) where Toyama Trough (TT) causes a discontinuity of the along shelf-current, numerical experiments were performed using two-layered ocean model with simplified bottom topography. When a current trapped by the continental slope representing an offshore branch of TWC (OB) encounters the NP and TT, the OB was trapped by the coast facing the TT. A clockwise lee-eddy developed between a current axis and a coastline over the TT, which results in a current path transition offshore (CPT). The OB finally adjusted to a current path which crosses TT by shifting from the discontinuity point of the continental slope. If a coastal current representing a coastal branch of the TWC (CB) developed under this situation, the CB also formed lee-eddy within the identical region of the OB’s eddy, resulting in CPT. Period for the CPT of the CB was shorter with increase of the OB volume transport. These results indicate that the OB acted to accelerate CPT of the CB within the TT. To support these results, observational data comprising mooring current, tidal, and CTD measurements obtained in and around the TT, along with the output from high-resolution data-assimilated ocean model DR_C were analyzed. Although the lee-eddy of the CBs was generated in every summer, the CPT events did not fully develop when the OB was absent over the continental slope because of the slow growth rate of the lee-eddy.
AB - To clarify the Tsushima Warm Current (TWC) system around a downstream region of Noto Peninsula (NP) where Toyama Trough (TT) causes a discontinuity of the along shelf-current, numerical experiments were performed using two-layered ocean model with simplified bottom topography. When a current trapped by the continental slope representing an offshore branch of TWC (OB) encounters the NP and TT, the OB was trapped by the coast facing the TT. A clockwise lee-eddy developed between a current axis and a coastline over the TT, which results in a current path transition offshore (CPT). The OB finally adjusted to a current path which crosses TT by shifting from the discontinuity point of the continental slope. If a coastal current representing a coastal branch of the TWC (CB) developed under this situation, the CB also formed lee-eddy within the identical region of the OB’s eddy, resulting in CPT. Period for the CPT of the CB was shorter with increase of the OB volume transport. These results indicate that the OB acted to accelerate CPT of the CB within the TT. To support these results, observational data comprising mooring current, tidal, and CTD measurements obtained in and around the TT, along with the output from high-resolution data-assimilated ocean model DR_C were analyzed. Although the lee-eddy of the CBs was generated in every summer, the CPT events did not fully develop when the OB was absent over the continental slope because of the slow growth rate of the lee-eddy.
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U2 - 10.1007/s10872-021-00601-w
DO - 10.1007/s10872-021-00601-w
M3 - Article
AN - SCOPUS:85105395113
VL - 77
SP - 685
EP - 701
JO - Journal of Oceanography
JF - Journal of Oceanography
SN - 0916-8370
IS - 4
ER -