A surface velocity spiral observed with ADCP and HF radar in the Tsushima Strait

Y. Yoshikawa, Takeshi Matsuno, K. Marubayashi, K. Fukudome

研究成果: ジャーナルへの寄稿記事

33 引用 (Scopus)

抄録

The structure of a wind-driven flow in the Tsushima Strait is investigated with moored acoustic Doppler current profiler (ADCP) and HF radar. Two ADCPs of high and low acoustic frequencies are simultaneously used to measure velocities in both the surface boundary layer and the interior with high resolutions. The velocity relative to an interior flow in the surface boundary layer is estimated by subtracting the reference velocity (estimated from velocities at greater depths) from a velocity in the surface layer, and complex principal component analysis (PCA) of the lagged wind stress and the relative velocity is performed. Despite a short (2 weeks) observation period of relatively calm and variable wind, a clockwise velocity spiral similar to a theoretical Ekman spiral is detected as the first mode of PCA. Ekman transport estimated from the relative velocities of the first mode agrees best with Ekman transport expected from wind stress of the first mode with 11-13 hours time lag, for which the explained variance of the first mode is also largest. This indicates that a wind-driven flow is balanced with wind stress after 11-13 hours, half of the inertial period at this latitude. Eddy viscosity is also inferred from wind stress and the relative velocities of the first mode. It is found to increase from O(10-3) m2 s-1 at greater depth to O(10-2) m2 s-1 near the sea surface.

元の言語英語
記事番号C06022
ジャーナルJournal of Geophysical Research: Oceans
112
発行部数6
DOI
出版物ステータス出版済み - 6 8 2007

Fingerprint

straits
radar
Acoustic Doppler Current Profiler
strait
acoustics
Radar
Acoustics
Wind stress
wind stress
Ekman transport
surface layer
principal components analysis
Principal component analysis
principal component analysis
boundary layers
Boundary layers
boundary layer
eddy viscosity
overland flow
acoustic frequencies

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Oceanography
  • Forestry
  • Aquatic Science
  • Ecology
  • Condensed Matter Physics
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Physical and Theoretical Chemistry
  • Polymers and Plastics
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Materials Chemistry
  • Palaeontology

これを引用

A surface velocity spiral observed with ADCP and HF radar in the Tsushima Strait. / Yoshikawa, Y.; Matsuno, Takeshi; Marubayashi, K.; Fukudome, K.

:: Journal of Geophysical Research: Oceans, 巻 112, 番号 6, C06022, 08.06.2007.

研究成果: ジャーナルへの寄稿記事

Yoshikawa, Y. ; Matsuno, Takeshi ; Marubayashi, K. ; Fukudome, K. / A surface velocity spiral observed with ADCP and HF radar in the Tsushima Strait. :: Journal of Geophysical Research: Oceans. 2007 ; 巻 112, 番号 6.
@article{3693aa8d2ff644bf87d7f72206e4c6ec,
title = "A surface velocity spiral observed with ADCP and HF radar in the Tsushima Strait",
abstract = "The structure of a wind-driven flow in the Tsushima Strait is investigated with moored acoustic Doppler current profiler (ADCP) and HF radar. Two ADCPs of high and low acoustic frequencies are simultaneously used to measure velocities in both the surface boundary layer and the interior with high resolutions. The velocity relative to an interior flow in the surface boundary layer is estimated by subtracting the reference velocity (estimated from velocities at greater depths) from a velocity in the surface layer, and complex principal component analysis (PCA) of the lagged wind stress and the relative velocity is performed. Despite a short (2 weeks) observation period of relatively calm and variable wind, a clockwise velocity spiral similar to a theoretical Ekman spiral is detected as the first mode of PCA. Ekman transport estimated from the relative velocities of the first mode agrees best with Ekman transport expected from wind stress of the first mode with 11-13 hours time lag, for which the explained variance of the first mode is also largest. This indicates that a wind-driven flow is balanced with wind stress after 11-13 hours, half of the inertial period at this latitude. Eddy viscosity is also inferred from wind stress and the relative velocities of the first mode. It is found to increase from O(10-3) m2 s-1 at greater depth to O(10-2) m2 s-1 near the sea surface.",
author = "Y. Yoshikawa and Takeshi Matsuno and K. Marubayashi and K. Fukudome",
year = "2007",
month = "6",
day = "8",
doi = "10.1029/2006JC003625",
language = "English",
volume = "112",
journal = "Journal of Geophysical Research",
issn = "0148-0227",
publisher = "American Geophysical Union",
number = "6",

}

TY - JOUR

T1 - A surface velocity spiral observed with ADCP and HF radar in the Tsushima Strait

AU - Yoshikawa, Y.

AU - Matsuno, Takeshi

AU - Marubayashi, K.

AU - Fukudome, K.

PY - 2007/6/8

Y1 - 2007/6/8

N2 - The structure of a wind-driven flow in the Tsushima Strait is investigated with moored acoustic Doppler current profiler (ADCP) and HF radar. Two ADCPs of high and low acoustic frequencies are simultaneously used to measure velocities in both the surface boundary layer and the interior with high resolutions. The velocity relative to an interior flow in the surface boundary layer is estimated by subtracting the reference velocity (estimated from velocities at greater depths) from a velocity in the surface layer, and complex principal component analysis (PCA) of the lagged wind stress and the relative velocity is performed. Despite a short (2 weeks) observation period of relatively calm and variable wind, a clockwise velocity spiral similar to a theoretical Ekman spiral is detected as the first mode of PCA. Ekman transport estimated from the relative velocities of the first mode agrees best with Ekman transport expected from wind stress of the first mode with 11-13 hours time lag, for which the explained variance of the first mode is also largest. This indicates that a wind-driven flow is balanced with wind stress after 11-13 hours, half of the inertial period at this latitude. Eddy viscosity is also inferred from wind stress and the relative velocities of the first mode. It is found to increase from O(10-3) m2 s-1 at greater depth to O(10-2) m2 s-1 near the sea surface.

AB - The structure of a wind-driven flow in the Tsushima Strait is investigated with moored acoustic Doppler current profiler (ADCP) and HF radar. Two ADCPs of high and low acoustic frequencies are simultaneously used to measure velocities in both the surface boundary layer and the interior with high resolutions. The velocity relative to an interior flow in the surface boundary layer is estimated by subtracting the reference velocity (estimated from velocities at greater depths) from a velocity in the surface layer, and complex principal component analysis (PCA) of the lagged wind stress and the relative velocity is performed. Despite a short (2 weeks) observation period of relatively calm and variable wind, a clockwise velocity spiral similar to a theoretical Ekman spiral is detected as the first mode of PCA. Ekman transport estimated from the relative velocities of the first mode agrees best with Ekman transport expected from wind stress of the first mode with 11-13 hours time lag, for which the explained variance of the first mode is also largest. This indicates that a wind-driven flow is balanced with wind stress after 11-13 hours, half of the inertial period at this latitude. Eddy viscosity is also inferred from wind stress and the relative velocities of the first mode. It is found to increase from O(10-3) m2 s-1 at greater depth to O(10-2) m2 s-1 near the sea surface.

UR - http://www.scopus.com/inward/record.url?scp=34548331371&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=34548331371&partnerID=8YFLogxK

U2 - 10.1029/2006JC003625

DO - 10.1029/2006JC003625

M3 - Article

AN - SCOPUS:34548331371

VL - 112

JO - Journal of Geophysical Research

JF - Journal of Geophysical Research

SN - 0148-0227

IS - 6

M1 - C06022

ER -