Observations of the frontal region of a buoyant river plume using an autonomous underwater vehicle

TitleObservations of the frontal region of a buoyant river plume using an autonomous underwater vehicle
Publication TypeJournal Article
Year of Publication2014
AuthorsRogowski P, Terrill E, Chen J.L
JournalJournal of Geophysical Research-Oceans
Volume119
Pagination7549-7567
Date Published2014/11
Type of ArticleArticle
ISBN Number2169-9275
Accession NumberWOS:000346102900011
Keywordsadcp data use; autonomous underwater vehicle; channel plume; coastal; Coastal dynamics; colored dissolved organic matter; estuaries; far-field; flow characteristics; model; near-field; New River Inlet; North Carolina; objective analysis; practical aspects; quantification; quasi-3d nearshore circulation; river plumes; South Atlantic Bight; vessel measurements; waters
Abstract

To characterize the transitional region from the near-field to far-field of a river plume entering coastal waters, we conducted four surveys using an autonomous underwater vehicle (AUV) to target the outflow of the New River Inlet, North Carolina, during maximum ebb tide. The utilization of a mobile sensor to synoptically observe current velocity data in tandem with natural river plume tracers (e.g., colored dissolved organic matter, salinity) was essential in understanding the mechanisms driving the observed circulation and mixing patterns within these waters. We find that this region is regularly impacted by two primary processes: (1) the interaction of an old dredged channel plume with the main discharge and (2) the recirculation of the discharge plume by an eddy that persistently forms between the old channel and main discharge location. Wind-driven processes in the nearshore can enhance the interaction of these two plumes resulting in unstable regions where mixing of the merged plume with the receiving waters is accelerated. We also conduct comparisons between AUV velocity observations from two surveys and their corresponding velocity outputs from a parallelized quasi-3-D model. We conclude that the ability to observe the estuarine outflow transitional region at near-synoptic temporal scales and resolutions discussed in this paper is key in providing the mechanisms driving local circulation which is essential for proper parameterization of high-resolution numerical coastal models. Key Points Wind-driven processes in the nearshore can enhance mixing of discharge plumes Synoptic observations are key to understanding the structure of dynamic plume discharges Choosing appropriate hydrodynamic model parameters can be accomplished using AUV data

DOI10.1002/2014jc010392
Short TitleJ Geophys Res-Oceans
Integrated Research Themes: 
Student Publication: 
No