Strong Inland Propagation of Low-Frequency Long Waves in River Estuaries
Sponsor
This work is supported by the project “Coping with deltas in transition” within the Programme of Strategic Scientific Alliances between China and the Netherlands (PSA), financed by the Ministry of Science and Technology of the People's Republic of China (MOST) (No. 2016YFE0133700) and the Royal Netherlands Academy of Arts and Sciences (Koninklijke Nederlandse Akademie van Wetenschappen [KNAW]) (No. PSA‐SA‐E‐02), and also partly by MOST (No. 2017YFE0107400), the National Natural Science Foundation of China (Nos. 51739005 and 41876091), Science and Technology Commission of Shanghai Municipality (Nos. 18DZ1206400, 19QA1402900, and 20DZ1204700), and the Fundamental Research Funds for the Central Universities. We thank two anonymous reviewers for their constructive comments and suggestions.
Published In
Geophysical Research Letters
Document Type
Citation
Publication Date
10-16-2020
Abstract
Tidal waves traveling into estuaries are modified by channel geometry and river flow. The damping effect of river flow on incident astronomical tides is well documented, whereas its impact on low‐frequency tides like MSf and Mm is poorly understood. In this contribution, we employ a numerical model to explore low‐frequency tidal behavior under varying river flow. MSf and Mm are locally generated by frictional mechanisms inside an estuary, and they are larger in amplitude far upstream in tidal rivers and persist landward of the point of tidal extinction. Increasing river flow nonlinearly modulates the longitudinal variations of MSf and Mm amplitudes. This is dynamically explained by flow‐enhanced asymmetry in subtidal friction over the spring‐neap (MSf) and perigee‐apogee (Mm) cycles, respectively. Estuaries act as frequency filters, where low‐frequency waves decay at a smaller rate and propagate more inland than high‐frequency waves. Strong inland penetration of low‐frequency tides informs compound flood management.
Rights
©2020. American Geophysical Union. All Rights Reserved.
Locate the Document
DOI
10.1029/2020GL089112
Persistent Identifier
https://archives.pdx.edu/ds/psu/34501
Citation Details
Guo, L., Zhu, C., Wu, X., Wan, Y., Jay, D. A., Townend, I., Wang, Z. B., & He, Q. (2020). Strong Inland Propagation of Low‐Frequency Long Waves in River Estuaries. Geophysical Research Letters, 47(19). https://doi.org/10.1029/2020gl089112