X-band radar mapping of morphological changes at a dynamic coastal inlet

TitleX-band radar mapping of morphological changes at a dynamic coastal inlet
Publication TypeJournal Article
Year of Publication2018
AuthorsRogowski P, de Paolo T., Terrill E, McNinch J.
JournalJournal of Geophysical Research-Earth Surface
Volume123
Pagination3034-3054
Date Published2018/11
Type of ArticleArticle
ISBN Number2169-9003
Accession NumberWOS:000453003800016
Keywordsbathymetry estimation; cbathy; coastal mapping; Ebb tidal delta; Geology; growth; inlet migration; migration; model; navigational hazards; nearshore bar behavior; observations; seasonal closure; tidal inlet; video; wave; X-band radar
Abstract

Remote sensing of the complex interactions between bathymetry, tidal flow, and waves in coastal inlets provides high-resolution data sets that can be exploited to characterize the morphological variability of shallow ebb tidal deltas (ETD). Here we used observations from a mobile X-band radar platform to determine optimal conditions during which radar-derived shoal signatures best represent positions of underlying shoals. Significant increases in the spatial errors of radar shoal signatures were observed when offshore wave energy intensified. Consequently, the lowest spatial errors occurred when the radar shoal signatures were primarily a function of the tidal flow (i.e., low sea state). We used these findings to quantify shoal migration patterns at the New River Inlet, North Carolina. We found that the southwestern portion of the ETD had the largest morphological variability with typical shoreward migration rates of 2-3m/day driven by incident wave energy. The migration rates and patterns estimated from X-band observations were consistent with numerical modeling results and a previous video-based New River remote sensing study. Our results confirm that X-band radar can be used to quickly map shallow ETDs (e.g., 5min of observations), allowing for rapid morphological assessments from shore or boat-based platforms. The methods would prove particularly useful for initial assessment as well as continual monitoring of dynamic tidal inlets where large morphological responses can be rapidly assessed and used for geomorphological studies, and as decision aids for maritime or engineering operations.

Plain Language Summary The manuscript presents a method for determination of the appropriate times when X-band-derived shoal signature positions best correlate with underlying (true) shoal positions. When these times are defined, small-scale shoal features can be tracked and their spatial and temporal migration patterns assessed.

DOI10.1029/2018jf004676
Short TitleJ. Geophys. Res.-Earth Surf.
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