博士 / 國立臺灣大學 / 海洋學系 / 84 / A 3-dimensional model is used to study the dispersal and flow
structure of the Yin-Yang Bay plume as well as basic dynamics
of small-scale plumes under the influence of tides and winds.
Forced by winds and tides, the plume structure is
4-dimensional. Tidal current advects plumes and shortens the
time scale needed for the Earth''s rotation effect to set in,
resulting in an asymmetric plume dispersal under the influence
of flood and ebb tide. For winds, the nearshore Ekman drift is
retarded by sea level setup or setdown. Therefore plumes are
dispersed by local winds primarily in the downwind direction.
Wind-induced and plume-forced flow fields are interactive.
Plume enhances stratification that in turn accelerates the wind-
driven current; wind-driven current then alters the plume
dispersal. Outside the Yin-Yang Bay, the plume is aymmetrically
advected by alongshore tides during flood and ebb periods
respectively. Ebb current forces the plume to hug the coast,
while flood current does not do so. Inside the Bay, there are
recirculation eddies induced by the bay geometry. Plume
movements induced by eddies are out of phase with the tidal
currents over the shelf. Southerly winds are the most effective
in dispersing plumes afar. Northerly winds compresses plume
water shoreward and results in much less dispersal. Alongshore
winds (easterly and westerly winds) drive strong downwind
currents that effectively advect and dilute plume water away.
Inside the bay, plumes are confined to the leeward half of the
basin by local winds as well as by eddies produced by
alongshore currents. Although plume dispersals are mostly
symmetric under easterly and westerly winds, the vertical
structure of cross-shelf flow under easterly wind favors
offshore dispersal of plume water, but acts in the opposite way
under westerly wind.
| Identifer | oai:union.ndltd.org:TW/084NTU00279003 |
| Date | January 1996 |
| Creators | Lin, Chun-Te, 林俊德 |
| Contributors | Chao, Shenn-Yu; Fan, Kuang-Lung, 趙慎餘﹔范光龍 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 261 |
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