Offshore detachment process of the low-salinity water around Changjiang Bank in the East China Sea

Jae Hong Moon, Naoki Hirose, Jong Hwan Yoon, Ig Chan Pang

    Research output: Contribution to journalArticle

    48 Citations (Scopus)

    Abstract

    A patchlike structure of low-salinity water detached from the Chanjiang "Diluted Water" (CDW) is frequently observed in the East China Sea (ECS). In this study, the offshore detachment process of CDW into the ECS is examined using a three-dimensional numerical model. The model results show that low-salinity water is detached from the CDW plume by the intense tide-induced vertical mixing during the spring tide period when the tidal current becomes stronger. During the spring tide, thickness of the bottom mixed layer in the sloping bottom around Changjiang Bank reaches the mean water depth, implying that the stratification is completely destroyed in the entire water column. As a result, the offshore detachment of CDW occurs in the sloping side of the bank where the tidal energy dissipation is strong enough to overcome the buoyancy effect during this period. On the other hand, the surface stratification is retrieved during the neap tide period, because the tidal current becomes substantially weaker than that in the spring tide. Wind forcing over the ECS as well as tidal mixing is a critical factor for the detachment process because the surface wind primarily induces a northeastward CDW transport across the shelf region where tide-induced vertical mixing is strong. Moreover, the wind-enhanced cross-isobath transport of CDW causes a larger offshore low-salinity patch, indicating that the freshwater volume of the low-salinity patch closely depends on the wind magnitude.

    Original languageEnglish
    Pages (from-to)1035-1053
    Number of pages19
    JournalJournal of Physical Oceanography
    Volume40
    Issue number5
    DOIs
    Publication statusPublished - May 1 2010

    Fingerprint

    tide
    vertical mixing
    tidal current
    water
    stratification
    salinity
    wind forcing
    energy dissipation
    surface wind
    buoyancy
    mixed layer
    sea
    water salinity
    water depth
    plume
    water column

    All Science Journal Classification (ASJC) codes

    • Oceanography

    Cite this

    Offshore detachment process of the low-salinity water around Changjiang Bank in the East China Sea. / Moon, Jae Hong; Hirose, Naoki; Yoon, Jong Hwan; Pang, Ig Chan.

    In: Journal of Physical Oceanography, Vol. 40, No. 5, 01.05.2010, p. 1035-1053.

    Research output: Contribution to journalArticle

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    abstract = "A patchlike structure of low-salinity water detached from the Chanjiang {"}Diluted Water{"} (CDW) is frequently observed in the East China Sea (ECS). In this study, the offshore detachment process of CDW into the ECS is examined using a three-dimensional numerical model. The model results show that low-salinity water is detached from the CDW plume by the intense tide-induced vertical mixing during the spring tide period when the tidal current becomes stronger. During the spring tide, thickness of the bottom mixed layer in the sloping bottom around Changjiang Bank reaches the mean water depth, implying that the stratification is completely destroyed in the entire water column. As a result, the offshore detachment of CDW occurs in the sloping side of the bank where the tidal energy dissipation is strong enough to overcome the buoyancy effect during this period. On the other hand, the surface stratification is retrieved during the neap tide period, because the tidal current becomes substantially weaker than that in the spring tide. Wind forcing over the ECS as well as tidal mixing is a critical factor for the detachment process because the surface wind primarily induces a northeastward CDW transport across the shelf region where tide-induced vertical mixing is strong. Moreover, the wind-enhanced cross-isobath transport of CDW causes a larger offshore low-salinity patch, indicating that the freshwater volume of the low-salinity patch closely depends on the wind magnitude.",
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