| 摘要: | 河口羽流在河海交界處扮演著重要的角色，不僅是海水與淡水交換的重要地點，也
是眾多生物聚集的棲息地，更是河流污染物進入海洋的第一道防線。河口羽流的範圍和
變動受多種因素影響，目前尚未有一套固定的界定標準。水質變化是研究河口羽流變動
的一個重要指標，本研究利用多衛星觀測，選定台灣地區的淡水河、蘭陽溪、高屏溪以
及卑南溪四條河流作為研究範圍，進行河口水質分析，以深入瞭解羽流的變化。研究中
使用了可視化光學波長（Apparent Visible Wavelength, AVW）作為基於遙測反射率計算
的指數，來表示水色的變化，並結合葉綠素濃度、漫射衰減係數、有色可溶性有機物、
總懸浮固體以及沙奇盤深度等五種水質指數進行分析。透過1998年至2023年的多衛星
觀測數據和模式整合，使用月平均數據和經驗正交函數分析方法探討河口區域水質的時
空變化。研究發現，淡水河的河口羽流主要向西南方擴散，蘭陽溪則向東南方擴散，高
屏溪向西北方擴散，而卑南溪則向兩側擴散。水質指數與AVW的相關性在高屏溪最為
顯著，其中，總懸浮固體與AVW在所有河口中相關性超過0.5，是與AVW關聯性最強
的參數。此外，本研究也探討了使用500nm、520nm和525nm的AVW閾值來界定河口
羽流範圍，發現520nm雖然適合，但不能與陸地形成封閉區域，525nm在大多數情況下
能與陸地形成封閉區域，因此，525nm是最適合用於界定河口羽流範圍的AVW;River plumes play a crucial role at the river-ocean interface, serving not only as a site for
the exchange of seawater and freshwater but also as a habitat for numerous organisms and the
first line of defense against riverine pollutants entering the ocean. The dynamics and extent of
river plumes are influenced by various factors, and there is currently no fixed standard for their
delineation. Water quality variation is an important indicator for studying changes in river
plumes. This study utilizes multi-satellite observations to analyze estuarine water quality in four
rivers in Taiwan: the Danshui River, Lanyang River, Gaoping River, and Beinan River, aiming
to gain a deeper understanding of plume dynamics. Apparent Visible Wavelength (AVW), an
index based on remote sensing reflectance calculations, is used to represent changes in water
color, combined with five different water quality indices including chlorophyll concentration,
diffuse attenuation coefficient, colored dissolved organic matter, total suspended solids, and
Secchi disk depth. By integrating data from multi-satellite observations from 1998 to 2023 and
using monthly average data and Empirical Orthogonal Function (EOF) analysis, the study
discusses the spatiotemporal variations in water quality in estuarine regions. The findings
indicate that the river plume from the Danshui River primarily disperses towards the southwest
of the estuary, while the Lanyang River disperses towards the southeast, the Gaoping River
towards the northwest, and the Beinan River disperses on both sides of the estuary. The
correlation between water quality indices and AVW is most significant in the Gaoping River
area, with Total Suspended Matter (TSM) showing the strongest correlation with AVW across
all estuaries, exceeding 0.5. Additionally, the study examines the use of AVW thresholds at 500
nm, 520 nm, and 525 nm for delineating river plume extents. Although 520 nm is suitable, it
does not form a closed area with the land, whereas 525 nm does form a closed area with the
land in most cases, making it the most appropriate AVW threshold for delineating the extent of
river plumes |
