Intratidal and spatial variability over a slope in the Ems estuary: Robust along-channel SPM transport versus episodic events. (30th September 2020)

• Record Type: Journal Article
• Authors: Schulz, Kirstin; Burchard, Hans; Mohrholz, Volker; Holtermann, Peter; Schuttelaars, Henk M.; Becker, Marius; Maushake, Christian; Gerkema, Theo
• Is Part Of: Estuarine, coastal and shelf science. Volume 243(2020)
• Publication Date: 2020-09-30
• Subjects: Lateral circulation -- SPM transport -- Ems estuary -- EDoM18; Estuarine oceanography -- Periodicals; Coasts -- Periodicals; Estuarine biology -- Periodicals; Seashore biology -- Periodicals; Coasts; Estuarine biology; Estuarine oceanography; Seashore biology; Periodicals; 551.461805
• DOI: 10.1016/j.ecss.2020.106902
• Languages: English
• ISSNs: 0272-7714

Abstract

Abstract: Results from measurements are presented that were collected during a full tidal cycle in the Ems estuary, involving two landers and an anchored research vessel. The conditions were characterized by very weak winds, no wave effects, and low river run-off, so that the state was close to tide-only. We find that the lateral (i.e., cross-slope) transport of water and suspended particulate matter (SPM) much of the time shows a vertically layered structure, which is however subject to sudden transitions. Moreover, even on the small spatial scale of these measurements (i.e., within a distance of 200 m), a strong lateral variability is observed in the circulation patterns. We analyze its dynamics by means of dimensionless parameters. In addition, near-bottom peaks in SPM concentration are observed, notably during early flood. However, these episodic events have little effect on the overall transport of SPM, which involves the whole water column: the measurements show a high vertically integrated SPM signal during late ebb, resulting in an ebb-dominance in the transport at this position in the tidal channel. Highlights: Lateral transport of water and SPM mostly shows a vertically layered structure, but is subject to abrupt transitions. Strong spatial variability is observed in the lateral circulation patterns. Small-scale and episodic events have little effect on the overall transport of SPM, which is ebb-dominated.