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題 名 | 以數值模式探討曾文溪口異重流傳遞過程=A Numerical Investigation of Density Currents in the Zengwen River Mouth |
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作 者 | 鮑俊宏; 陳佳琳; | 書刊名 | 海洋工程學刊 |
卷 期 | 19:1 2023.11[民112.11] |
頁 次 | 頁23-38 |
分類號 | 351.81 |
關鍵詞 | 河口; 內陸棚; 曾文溪; 異重流; River mouth; Inner continental shelf; Zengwen River; Density current; Regional ocean modeling system; ROMS; |
語 文 | 中文(Chinese) |
DOI | 10.6266/JOCOE.202311_19(1).0003 |
中文摘要 | 台灣多數河川於颱洪期間輸出大量的沉積物,對於近岸或是內陸棚的地形變遷有著重大影響, 尤其曾文溪口有近海海床淘刷或海底管線懸空等現象,其成因或與大量沉積物造成之異重流有關。 因此本研究透過三維數值模式 Regional Ocean Modeling System (ROMS) 分項探討曾文溪河口波 浪、潮汐以及洪水入流之相關營力,說明異重流傳遞過程的時空分布情形。模式結果顯示鄰近曾文 溪口之舊河道為異重流自加速區域,漲潮時刻北向的潮流將高濃度的懸浮沉積物濃度攜往該區,有 助於產生異重流。當考慮波浪、極端流量與潮汐,三者交互作用下,西南向波浪造成的沿岸流,抑制 懸浮沉積物濃度西向傳輸,造成異重流發生時程縮短且次數變少。模擬過程另顯示舊河道於極端 流量與潮汐交互作用時,先後發生 2 次異重流事件,終將水深 100 公尺處之舊河道終點刷深超過 1 公尺。 |
英文摘要 | During typhoon-induced flood events, Taiwanese rivers often supply significant amounts of sediment, which has a major impact on coastal and continental shelf. Prior study suggests that density currents cause seabed scouring and suspension of underwater pipelines near Zengwen River mouth. In this study, a three-dimensional numerical model, ROMS, is utilized to simulate the temporal and spatial distribution of density currents and examine the interactions of waves, tides, and river plumes in Zengwen River mouth. The model results indicate that the slope of old river channel adjacent to the Zengwen River mouth is in the self-acceleration regime of density currents. The northward tidal currents during high tide carry high suspended sediment concentration, contributing to the occurrence of density currents. Model results further indicate that density current events in the old river channel lead to substantial erosion, where the seabed at a depth of 100 meters is eroded by over 1 meter. However, under the southwesterly wind-wave condition, wave-induced currents constrain the westward transport of suspended sediment, reducing the frequency and duration of density current events. |
本系統中英文摘要資訊取自各篇刊載內容。