Print Email Facebook Twitter River-tide dynamics: Exploration of nonstationary and nonlinear tidal behavior in the Yangtze River estuary Title River-tide dynamics: Exploration of nonstationary and nonlinear tidal behavior in the Yangtze River estuary Author Guo, L. Van der Wegen, M. Jay, D.A. Matte, P. Wang, Z.B. Roelvink, J.A. He, Q. Faculty Civil Engineering and Geosciences Department Hydraulic Engineering Date 2015-05-19 Abstract River-tide dynamics remain poorly understood, in part because conventional harmonic analysis (HA) does not cope effectively with nonstationary signals. To explore nonstationary behavior of river tides and the modulation effects of river discharge, this work analyzes tidal signals in the Yangtze River estuary using both HA in a nonstationary mode and continuous wavelet transforms (CWT). The Yangtze is an excellent natural laboratory to analyze river tides because of its high and variable flow, its length, and the fact that there are do dams or reflecting barriers within the tidal part of the system. Analysis of tidal frequencies by CWT and analysis of subtidal water level and tidal ranges reveal a broad range of subtidal variations over fortnightly, monthly, semiannual, and annual frequencies driven by subtidal variations in friction and by variable river discharges. We employ HA in a nonstationary mode (NSHA) by segregating data within defined flow ranges into separate analyses. NSHA quantifies the decay of the principal tides and the modulation of M4 tide with increasing river discharges. M4 amplitudes decrease far upriver (landward portion of the estuary) and conversely increase close to the ocean as river discharge increases. The fortnightly frequencies reach an amplitude maximum upriver of that for over tide frequencies, due to the longer wavelength of the fortnightly constituents. These methods and findings should be applicable to large tidal rivers globally and have broad implications regarding management of navigation channels and ecosystems in tidal rivers. To reference this document use: http://resolver.tudelft.nl/uuid:83ae752a-4de3-4b0b-aae5-bf691dece2b6 Publisher American Geophysical Union Embargo date 2015-11-19 ISSN 2169-9291 Source https://doi.org/10.1002/2014JC010491 Source Journal of Geophysical Research: Oceans, 120 (5), 2015 Part of collection Institutional Repository Document type journal article Rights (c) 2015 American Geophysical Union Files PDF Wang_2015.pdf 2.69 MB Close viewer /islandora/object/uuid:83ae752a-4de3-4b0b-aae5-bf691dece2b6/datastream/OBJ/view