An Analysis of the 8.85- and 4.42-Year Cycles in the Gulf of Maine

• Published in: Journal of Marine Science and Engineering
• Main Authors: Xiaolong Zong, Ruzhen Zhang, Shuwen Zhang, Fangjing Deng, Wei Zhou, Zhaoyun Chen
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2021
• Subjects: tidal nodal cycle; enhanced harmonic analysis; sea-level rise; 8.85-year cycle; 4.42-year cycle; Naval architecture. Shipbuilding. Marine engineering; VM1-989; Oceanography; GC1-1581; North Atlantic
• Online Access: https://doi.org/10.3390/jmse9121362; https://doaj.org/article/45a6a8d1a58042909f597710499a877b

In the background of global warming and climate change, nuisance flooding is only caused by astronomical tides, which could be modulated by the nodal cycle. Therefore, much attention should be paid to the variation in the amplitude of the nodal cycle. In this paper, we utilize the enhanced harmonic analysis method and the independent point scheme to obtain the time-dependent amplitudes of the 8.85-year cycle of N 2 tide and the 4.42-year cycle of 2N 2 tide based on water level records of four tide gauges in the Gulf of Maine. Results indicate that the long-term trends of N 2 and 2N 2 tides vary spatially, which may be affected by the sea-level rise, coastal defenses, and other possible climate-related mechanisms. The comparison between Halifax and Eastport reveals that the topography greatly influences the amplitudes of those cycles. Moreover, a quasi 20-year oscillation is obvious in the 8.85-year cycle of N 2 tide. This oscillation probably relates to a 20-year mode in the North Atlantic Ocean.