北海道西岸沖における水系分布と流れパターンの季節変化  [in Japanese] Seasonal Variations of Water System Distributions and Flow Patterns off the West Coast of Hokkaido  [in Japanese]

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Abstract

北海道西岸沖表層流の流れパターンの季節変化を調べるために,海洋観測資料と直接測流(ADCP・GEK)データを解析した。海面加熱期である夏季の対馬暖流は,水深約50m付近に高塩分水を伴う北上流である。この北上流は津軽海峡の西側では沿岸に接岸して強化され,さらに北側の石狩湾沖では時計回りの蛇行流の形成によって離岸する。しかし,この高塩分水は海面冷却期である冬季に入るとすぐに消滅する。この原因は強い海面冷却によって表層の低塩分水と鉛直混合したためと推測される。それゆえ,冬季から春季の対馬暖流は津軽海峡の西側では幅広い北上流として認められるものの,石狩湾よりも北側の海域では次第に弱まり,不明瞭な北上流となる。Hydrographic data and direct current velocity data (ADCP and GEK) were used to examine the seasonal variations of upper-ocean flow off the west coast of Hokkaido, Japan. During the summer season when the sea surface temperature increases, the Tsushima Warm Current (TWO) flows northward carrying more saline water in the intermediate layer (about 50 m depth). The current flows swiftly along the west coast of the Tsugaru Strait and diverts offshore at Ishikari Bay. This is caused by the presence of the local clockwise meandering current of the Bay. This saline water, however, abruptly disappears in the winter season when the surface temperature cools. This could be explained by the strong vertical mixing between the saline water in the surface and less saline water in the subsurface layer. Therefore, during the winter season, the northern flow of the TWC still exists near the Tsugaru Strait, but dissipates as it nears the Ishigaki Bay due to the vertical mixing of the layers.

Journal

  • Oceanography in Japan

    Oceanography in Japan 17(4), 223-240, 2008-07-05

    日本海洋学会

References:  28

Cited by:  2

  • Mode Waters Observed around Musashi Rise West of Hokkaido  [in Japanese]

    HIGAKI Naoyuki , ISODA Yutaka , HONDA Satoshi , Naoyuki Higaki , Yutaka Isoda , Satoshi Honda , 北海道立地質研究所 , 北海道大学大学院水産科学研究院 , 独立行政法人中央水産研究所 , Geological Survey of Hokkaido , Graduate School of Fisheries Sciences Hokkaido University , National Research Institute of Fisheries Science Fisheries Research Agency

    Oceanography in Japan 18(6), 335-350, 2009-11-05

    References (10) Cited by (1)

  • Wind-induced Shelf Waves off the West Coast of Hokkaido  [in Japanese]

    ISOGAI Yasuhiro , ISODA Yutaka , SHIMONO Manabu

    海と空 86(3), 45-60, 2011-03-31

    References (19)

Codes

  • NII Article ID (NAID)
    110006835255
  • NII NACSIS-CAT ID (NCID)
    AN10382760
  • Text Lang
    JPN
  • Article Type
    Journal Article
  • ISSN
    09168362
  • NDL Article ID
    9590280
  • NDL Source Classification
    ZM44(科学技術--地球科学--海洋・陸水・火山)
  • NDL Call No.
    Z15-778
  • Data Source
    CJP  CJPref  NDL  NII-ELS 
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