Spatiotemporal Variations of Tidal Asymmetry Along the Coast of Taiwan: Characteristics and Implications

Authors

• Ting-Chieh Lin, Department of Harbor and River Engineering, National Taiwan Ocean University, Keelung, 202301, Taiwan
• Tai-Wen Hsu, Department of Harbor and River Engineering, National Taiwan Ocean University, Keelung, 202301, Taiwan
• Tzu-Chun Huang, Department of Harbor and River Engineering, National Taiwan Ocean University, Keelung, 202301, Taiwan
• Chun-Yuan Lin, Center of Excellence for Ocean Engineering, National Taiwan Ocean University, Keelung 202301, TaiwanFollow

Abstract

This study presents the first systematic investigation into the spatiotemporal characteristics and evolutionary trends of tidal asymmetry along the coast of Taiwan from 2003 to 2022, employing a moving window method combined with the S_TIDE toolbox.  By quantifying the skewness of the Main Tidal Asymmetry Combinations (MTAC) and their temporal variations, the study reveals significant regional disparities between the eastern and western coasts.  The western coast is primarily dominated by the M2-M4 combination, with the northwestern region exhibiting a flood dominance pattern and the southwestern region characterized by ebb dominance.  Conversely, the eastern coast, attributed to its open topography and minimal tidal wave deformation, is mainly influenced by the O1-K1-M2 combination and displays weaker overall asymmetry.  Notably, the study identifies that specific regions, such as HsinChu and DongShi, are driven by variations in the amplitude of the shallow-water M4 constituent, leading to a significant intensification of tidal asymmetry over time.  Comparative analysis using satellite imagery demonstrates a strong correlation between shoreline evolution (e.g., erosion and accretion) and the observed trends in tidal asymmetry.  These findings elucidate the regional zonation and evolutionary trends of tidal asymmetry in Taiwan, offering a crucial quantitative scientific basis for coastal defense and adaptation strategies

Recommended Citation

Lin, Ting-Chieh; Hsu, Tai-Wen; Huang, Tzu-Chun; and Lin, Chun-Yuan (2026) "Spatiotemporal Variations of Tidal Asymmetry Along the Coast of Taiwan: Characteristics and Implications," Journal of Marine Science and Technology–Taiwan: Vol. 34: Iss. 3, Article 7.
DOI: 10.51400/2709-6998.2830
Available at: https://jmstt.ntou.edu.tw/journal/vol34/iss3/7