scholarly journals Analysis of tidal currents in the North Sea from shipboard acoustic Doppler current profiler data

2018 ◽  
Vol 162 ◽  
pp. 1-12 ◽  
Author(s):  
Håvard Vindenes ◽  
Kjell Arild Orvik ◽  
Henrik Søiland ◽  
Henning Wehde
Keyword(s):  
North Sea ◽  
Acoustic Doppler Current Profiler ◽  
Tidal Currents ◽  
The North ◽  
Current Profiler ◽  
The North Sea ◽  
Profiler Data

Dynamics of tidal mixing fronts in the North Sea

1993 ◽  
Vol 343 (1669) ◽  
pp. 431-446 ◽  
Keyword(s):  
North Sea ◽  
Baroclinic Instability ◽  
Acoustic Doppler Current Profiler ◽  
Hf Radar ◽  
Tidal Mixing ◽  
The North ◽  
Current Profiler ◽  
Shelf Sea ◽  
The North Sea ◽  
New Generation

Twenty years since the discovery of tidal mixing fronts there are still few convincing observations of the velocity field associated with these structures. Simple models of shelf sea fronts predict strong along-front jets, weaker convergent circulations and instabilities. During the North Sea Project a series of studies of the Flamborough frontal system has used a new approach based upon novel combinations of modern instrumentation (HF radar, acoustic Doppler current profiler, Decca-Argos drifting buoys and towed undulating CTD) and have provided one of the first directly observed pictures of shelf sea frontal circulation. Observational confirmation of jetlike along-front flow has been found together with evidence of cross-frontal convergence. A new generation of eddy-resolving models will help to focus the next phase of frontal circulation studies in relation to questions concerning baroclinic instability and eddy generation.

Benthos of a Sublittoral Sandbank in the Southern Bight of the North Sea: General Considerations

1982 ◽  
Vol 62 (3) ◽  
pp. 549-557 ◽  
Author(s):  
K. A. Willems ◽  
C. Vanosmael ◽  
D. Claeys ◽  
M. Vincx ◽  
C. Heip
Keyword(s):  
North Sea ◽  
Coastal Waters ◽  
High Energy ◽  
Tidal Currents ◽  
Physical Disturbance ◽  
Sea Floor ◽  
Southern Bight ◽  
The North ◽  
The North Sea

In two previous papers (Vanosmael et al. 1982; Willems et al. 1982) the macrofauna and meiofauna of a sublittoral sandbank in the Belgian coastal waters of the North Sea were described. This sandbank, the Kwinte Bank, is one of a series of parallel linear banks, the Flemish Banks, which are 15–25 km long and 3–6 km wide and rise about 25 m above the surrounding sea-floor. They are stressed, high-energy environments, subject to extreme physical disturbance by the very strong tidal currents which run parallel to the long axis of the sandbank and which put the whole upper layer of the sediment in a state of suspension at times.

Macrobenthos of a Sublittoral Sandbank in the Southern Bight of the North Sea

1982 ◽  
Vol 62 (3) ◽  
pp. 521-534 ◽  
Author(s):  
C. Vanosmael ◽  
K. A. Willems ◽  
D. Claeys ◽  
M. Vincx ◽  
C. Heip
Keyword(s):  
North Sea ◽  
Tidal Currents ◽  
English Channel ◽  
Marine Transgression ◽  
Sea Floor ◽  
Southern Bight ◽  
Glacial Origin ◽  
The North ◽  
Belgian Coast ◽  
The North Sea

In the Southern Bight of the North Sea, off the Belgian coast, exists a series of parallel sublittoral sandbanks, the Flemish Banks, situated in a southwest-northeastern direction, 15–25 km long and 3–6 km wide. They are separated by channels, 4–6 km wide, and rise about 25 m above the surrounding sea-floor (Fig. 1). These sandbanks resulted from the accumulation of sandy deposits of glacial origin sedimented by the giant stream draining the waters from the present Rhine, Meuse, Scheldt and Thames before the Flandrian marine transgression about 12000 years ago. When from boreal times onwards the North Sea became slowly inundated, a connexion existed with the small English Channel which gradually enlarged, resulting in the very strong tidal currents which are responsible for the present geomorphology of the region.

Extracting Meaningful Information from Uncalibrated Backscattered Echo Intensity Data

2010 ◽  
Vol 27 (5) ◽  
pp. 943-949 ◽  
Author(s):  
Louis Gostiaux ◽  
Hans van Haren
Keyword(s):  
Transmission Loss ◽  
Signal To Noise Ratio ◽  
Acoustic Doppler Current Profiler ◽  
Sediment Concentration ◽  
Original Method ◽  
Air Bubbles ◽  
Echo Intensity ◽  
The North ◽  
Current Profiler ◽  
The North Sea

Abstract The authors present an original method for the analysis of acoustic Doppler current profiler (ADCP) echo intensity profiles measured in the ocean, especially when no calibration has been performed. This study is based on data from Teledyne RD Instrument acoustic profilers but provides a methodology that can be extended to other kinds of hardware. To correctly interpret data for which the signal-to-noise ratio is below a factor of 10, the authors propose isolating the backscattered signal from noise in arithmetic space before resolving the sonar equation and compensating for transmission loss in logarithmic space. The robustness of the method is shown for several independent datasets from the Atlantic Ocean, the North Sea, and the Mediterranean Sea. Estimation of sediment concentration, planktonic migrations, or air bubbles is now possible at less than 10 dB above noise level, which can concern half of the ADCP’s range under common circumstances.

scholarly journals GIANT AND MEGA RIPPLES IN THE GERMAN BIGHT AND STUDIES OF THEIR MIGRATION IN A TESTING AREA

1974 ◽  
Vol 1 (14) ◽  
pp. 59
Author(s):  
Horst Pasenau ◽  
Johannes Ulrich
Keyword(s):  
North Sea ◽  
German Bight ◽  
Tidal Currents ◽  
Tidal Channels ◽  
Testing Area ◽  
The North ◽  
The North Sea ◽  
Echo Sounding

In a lot of regions the bottom of the North Sea is covered with large ripple fields, especially in the estuaries and in the tidal channels. A great number of echo sounding profiles (29.500 n.m.) were evaluated to determine the boundaries of these areas and to describe the dimension of patterns. Special investigations of the hydrographic situation, the distribution of deposits and the migration of ripples under the influence of tidal currents only, were carried out in a testing area in the Lister Tief on 11 cruises since 1971.

Shape and size trends for sand waves in a depositional zone of the North Sea

1970 ◽  
Vol 107 (5) ◽  
pp. 469-477 ◽  
Author(s):  
A. H. Stride
Keyword(s):  
Continental Shelf ◽  
North Sea ◽  
Tidal Currents ◽  
British Isles ◽  
Progressive Decrease ◽  
Sand Waves ◽  
The North ◽  
Migration Direction ◽  
The North Sea ◽  
Shape And Size

SummaryA continuous profile of 430 large sand waves shows a progressive decrease in height (with some increasing crest separation) in their inferred migration direction, as well as showing the changing effectiveness of the ebb and flood tidal currents to move sand. The height of these and other sand waves around the British Isles is virtually unrelated to the depth of the sea, contrary to what has been suggested elsewhere. However, most sand waves occur on the continental shelf broadly because it is there that the currents reach a suitable range of speeds and sufficient sand is available at the present time.

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