scholarly journals Effects of tidal straining on the semidiurnal cycle of dissipation in the Rhine region of freshwater influence: Comparison of model and measurements

2008 ◽  
Vol 113 (C1) ◽  
Author(s):  
Alejandro J. Souza ◽  
Neil R. Fisher ◽  
John H. Simpson ◽  
M. John Howarth
Keyword(s):  
Tidal Straining ◽  
Freshwater Influence

scholarly journals The Formation of Turbidity Maximum Zones by Minor Axis Tidal Straining in Regions of Freshwater Influence

2020 ◽  
Vol 50 (5) ◽  
pp. 1265-1287
Author(s):  
Raúl P. Flores ◽  
Sabine Rijnsburger ◽  
Alexander R. Horner-Devine ◽  
Nirnimesh Kumar ◽  
Alejandro J. Souza ◽  
...  
Keyword(s):  
Tidal Flow ◽  
Vertical Mixing ◽  
Wave Model ◽  
Major Axis ◽  
Minor Axis ◽  
Turbidity Maximum ◽  
Freshwater Flux ◽  
Kelvin Wave ◽  
Tidal Straining ◽  
Freshwater Influence

AbstractThis study investigates the influence of tidal straining in the generation of turbidity maximum zones (TMZ), which are observed to extend for tens of kilometers along some shallow, open coastal seas. Idealized numerical simulations are conducted to reproduce the cross-shore dynamics and tidal straining in regions of freshwater influence (ROFIs), where elliptical current patterns are generated by the interaction between stratification and a tidal Kelvin wave. Model results show that tidal straining leads to cross-shore sediment convergence and the formation of a nearshore TMZ that is detached from the coastline. The subtidal landward sediment fluxes are created by asymmetries in vertical mixing between the stratifying and destratifying phases of the tidal cycle. This process is similar to the tidal straining mechanism that is observed in estuaries, except that in this case the convergence zone and TMZ are parallel to the shoreline and perpendicular to both the direction of the freshwater flux and the major axis of the tidal flow. We introduce the term minor axis tidal straining (MITS) to describe the tidal straining in these systems and to differentiate it from the tidal straining that occurs when the major axis of the tidal ellipse is aligned with the density gradient. The occurrence of tidal straining and the coastal TMZ is predicted in terms of the Simpson (Si) and Stokes (Stk) numbers, and top–bottom tidal ellipticity difference (Δε). Based on our results, we find that SiStk2 > 3 and Δε > 0.5 provide a limiting condition for the required density gradients and latitudes for the occurrence of MITS and the generation of a TMZ.

Tropical versus high latitude freshwater influence on the Atlantic circulation

2006 ◽  
Vol 27 (7-8) ◽  
pp. 715-725 ◽  
Author(s):  
Heiko Goelzer ◽  
Juliette Mignot ◽  
Anders Levermann ◽  
Stefan Rahmstorf
Keyword(s):  
High Latitude ◽  
Freshwater Influence

scholarly journals Processes impacting on stratification in a region of freshwater influence: Application to Liverpool Bay

2009 ◽  
Vol 114 (C11) ◽  
Author(s):  
F. Verspecht ◽  
T. P. Rippeth ◽  
M. J. Howarth ◽  
A. J. Souza ◽  
J. H. Simpson ◽  
...  
Keyword(s):  
Liverpool Bay ◽  
Freshwater Influence

Periodic Frontogenesis in a Region of Freshwater Influence

Estuaries ◽  
1993 ◽  
Vol 16 (1) ◽  
pp. 74 ◽  
Author(s):  
Jonathan Sharples ◽  
John H. Simpson
Keyword(s):  
Freshwater Influence

Impact of the Depth-to-Width Ratio of Periodically Stratified Tidal Channels on the Estuarine Circulation

2015 ◽  
Vol 45 (8) ◽  
pp. 2048-2069 ◽  
Author(s):  
Elisabeth Schulz ◽  
Henk M. Schuttelaars ◽  
Ulf Gräwe ◽  
Hans Burchard
Keyword(s):  
Eddy Viscosity ◽  
Transport Model ◽  
Stable Stratification ◽  
Estuarine Circulation ◽  
Width Ratio ◽  
Cross Sectional ◽  
Tidal Straining ◽  
The Individual ◽  
Periodic Stratification ◽  
The Impact

AbstractThe dependency of the estuarine circulation on the depth-to-width ratio of a periodically, weakly stratified tidal estuary is systematically investigated here for the first time. Currents, salinity, and other properties are simulated by means of the General Estuarine Transport Model (GETM) in cross-sectional slice mode, applying a symmetric Gaussian-shaped depth profile. The width is varied over four orders of magnitude. The individual along-channel circulation contributions from tidal straining, gravitation, advection, etc., are calculated and the impact of the depth-to-width ratio on their intensity is presented and elucidated. It is found that the estuarine circulation exhibits a distinct maximum in medium-wide channels (intermediate depth-to-width ratio depending on various parameters), which is caused by a maximum of the tidal straining contribution. This maximum is related to a strong tidal asymmetry of eddy viscosity and shear created by secondary strain-induced periodic stratification (2SIPS): in medium channels, transverse circulation generated by lateral density gradients due to laterally differential longitudinal advection induces stable stratification at the end of the flood phase, which is further increased during ebb by longitudinal straining (SIPS). Thus, eddy viscosity is low and shear is strong in the entire ebb phase. During flood, SIPS decreases the stratification so that eddy viscosity is high and shear is weak. The circulation resulting from this viscosity–shear correlation, the tidal straining circulation, is oriented like the classical, gravitational circulation, with riverine outflow at the surface and oceanic inflow close to the bottom. In medium channels, it is about 5 times as strong as in wide (quasi one-dimensional) channels, in which 2SIPS is negligible.

Vadicola aprostatus gen. nov., sp. nov., a marine oligochaete (Tubificidae; Rhyacodrilinae) from British Columbia

1982 ◽  
Vol 60 (12) ◽  
pp. 3232-3236 ◽  
Author(s):  
H. R. Baker
Keyword(s):  
British Columbia ◽  
Ejaculatory Duct ◽  
Coarse Sand ◽  
Prostate Cells ◽  
Freshwater Influence ◽  
Intertidal Habitats

Vadicola aprostatus gen. nov., sp. nov., a marine tubificid (Annelida; Oligochaeta) from intertidal habitats of British Columbia (usually coarse sand without obvious freshwater influence), is characterized by an internal projection in the ejaculatory duct and a lack of prostate cells on the atria. Vadicola aprostatus is placed in the subfamily Rhyacodrilinae.

scholarly journals The impact of storms and stratification on sediment transport in the Rhine region of freshwater influence

2017 ◽  
Vol 122 (5) ◽  
pp. 4456-4477 ◽  
Author(s):  
Raúl P. Flores ◽  
Sabine Rijnsburger ◽  
Alexander R. Horner-Devine ◽  
Alejandro J. Souza ◽  
Julie D. Pietrzak
Keyword(s):  
Sediment Transport ◽  
Freshwater Influence ◽  
The Impact

scholarly journals Characterization of a resilient seagrass meadow during a decline period

2018 ◽  
Vol 82 (1) ◽  
pp. 67 ◽  
Author(s):  
Bárbara Ondiviela ◽  
Lina Fernández ◽  
Araceli Puente ◽  
Gerardo García-Castrillo ◽  
José A. Juanes
Keyword(s):  
Seagrass Meadow ◽  
Large Population ◽  
Sea Surface ◽  
Biological Traits ◽  
Benthic Assemblages ◽  
Biomass Density ◽  
Zostera Noltei ◽  
Poor Understanding ◽  
Freshwater Influence

Seagrasses are globally threatened ecosystems with essential ecological roles. An important limitation in seagrass conservation efforts is the poor understanding of resilient meadows. The present work studies a meadow, which maintained a large population of Zostera marina and Zostera noltei, during the decline of seagrasses in the Bay of Santander (from 1984 to 2000). The work examines resilience parameters related to the biological traits (biomass, density, length and width of the leaves) and to the associated benthic assemblages. The maturity of the meadow and the changing environmental conditions induced by the torrential regime of the Miera River, have likely improved the resistance to the periods of stress. The adaptation to these fluctuating conditions is reflected in a high seasonal and spatial variability in the biomass, density, morphological traits and benthic assemblages. These variations are related to the summer peaks in the PAR, the sea surface temperature and the freshwater influence along the discharge of the Miera River. This work provides the first seagrass data in Cantabria. The data are dated in the early 2000s and constitute a baseline study for the Bay of Biscay.

scholarly journals Current structure in the Rhine region of freshwater influence

1997 ◽  
Vol 55 (2) ◽  
pp. 277-292 ◽  
Author(s):  
A. J. Souza ◽  
J. H. Simpson ◽  
F. Schirmer
Keyword(s):  
Current Structure ◽  
Freshwater Influence
Sign in / Sign up

Export Citation Format

Share Document