Coastally trapped waves, baroclinic eddies, internal tides and oceanic fronts at the shelf break: their implications for exchanges between shelf and oceanic waters

1981 ◽  
Vol 302 (1472) ◽  
pp. 661-661 ◽  
Keyword(s):  
Coastal Waters ◽  
Coastal Upwelling ◽  
Shelf Break ◽  
Internal Tides ◽  
Oceanic Fronts ◽  
Run Off ◽  
Break Surface ◽  
Seaward Edge ◽  
Coastally Trapped Waves ◽  
Topographic Rossby Waves

The seaward edge of the continental shelf, or shelf break, is the locus of strong physical variability in the overlying waters. Near the shelf-break, surface tides scatter energy into internal modes that propagate both onshore and offshore and produce strong vertical shears. Atmospheric forcing generates subinertial-frequency topographic Rossby waves, which propagate parallel to the coastline and are strongly trapped near the shelf break. Relative to the sloping topography, wind-driven coastal upwelling generates prograde fronts, and river run-off generates retrograde fronts. Located near the shelf break, these fronts are boundaries between oceanic and coastal waters. Oceanic eddies impinge on, and move along, the shelf-break entraining coastal waters. Eddies may also be shed by shelf-break fronts. Submarine capes and canyons contort the shelf break and significantly modify the enumerated processes. Based on observational evidence from a few coastal regimes, the shelf break is a zone where several mesoscale and synoptic-scale processes operate and probably produce significant turbulent transfers.

scholarly journals On the Dynamics of the Southern Senegal Upwelling Center: Observed Variability from Synoptic to Superinertial Scales

2017 ◽  
Vol 47 (1) ◽  
pp. 155-180 ◽  
Author(s):  
Xavier Capet ◽  
Philippe Estrade ◽  
Eric Machu ◽  
Siny Ndoye ◽  
Jacques Grelet ◽  
...  
Keyword(s):  
System Dynamics ◽  
Solitary Waves ◽  
Large Amplitude ◽  
Coastal Upwelling ◽  
Shelf Break ◽  
Internal Tides ◽  
Large Area ◽  
Thermohaline Structure ◽  
Field Campaign ◽  
It Impacts

AbstractUpwelling off southern Senegal and Gambia takes place over a wide shelf with a large area where depths are shallower than 20 m. This results in typical upwelling patterns that are distinct (e.g., more persistent in time and aligned alongshore) from those of other better known systems, including Oregon and Peru where inner shelves are comparatively narrow. Synoptic to superinertial variability of this upwelling center is captured through a 4-week intensive field campaign, representing the most comprehensive measurements of this region to date. The influence of mesoscale activity extends across the shelf break and far over the shelf where it impacts the midshelf upwelling (e.g., strength of the upwelling front and circulation), possibly in concert with wind fluctuations. Internal tides and solitary waves of large amplitude are ubiquitous over the shelf. The observations suggest that these and possibly other sources of mixing play a major role in the overall system dynamics through their impact upon the general shelf thermohaline structure, in particular in the vicinity of the upwelling zone. Systematic alongshore variability in thermohaline properties highlights important limitations of the 2D idealization framework that is frequently used in coastal upwelling studies.

The Run off of Nutrients from Funen, Denmark, and the Consequences for Its Coastal Waters

1991 ◽  
Vol 24 (10) ◽  
pp. 315-318
Author(s):  
J. D. Petersen ◽  
N. Rask ◽  
H. B. Madsen ◽  
S. E. Pedersen
Keyword(s):  
Coastal Waters ◽  
Run Off

Upwelling Bays: How Coastal Upwelling Controls Circulation, Habitat, and Productivity in Bays

2020 ◽  
Vol 12 (1) ◽  
pp. 415-447 ◽  
Author(s):  
John L. Largier
Keyword(s):  
Ocean Acidification ◽  
Wind Stress ◽  
Coastal Waters ◽  
Coastal Upwelling ◽  
Coastal Currents ◽  
Local Wind ◽  
Phytoplankton Blooms ◽  
Local Extrema ◽  
High Recruitment

Bays in coastal upwelling regions are physically driven and biochemically fueled by their interaction with open coastal waters. Wind-driven flow over the shelf imposes a circulation in the bay, which is also influenced by local wind stress and thermal bay–ocean density differences. Three types of bays are recognized based on the degree of exposure to coastal currents and winds (wide-open bays, square bays, and elongated bays), and the characteristic circulation and stratification patterns of each type are described. Retention of upwelled waters in bays allows for dense phytoplankton blooms that support productive bay ecosystems. Retention is also important for the accumulation of larvae, which accounts for high recruitment in bays. In addition, bays are coupled to the shelf ecosystem through export of plankton-rich waters during relaxation events. Ocean acidification and deoxygenation are a concern in bays because local extrema can develop beneath strong stratification.

Observation of Bottom‐Trapped Topographic Rossby Waves on the Shelf Break of the Chukchi Sea

2020 ◽  
Vol 125 (7) ◽  
Author(s):  
Ahyoung Ku ◽  
Young Ho Seung ◽  
Chanhyung Jeon ◽  
Youngseok Choi ◽  
Eri Yoshizawa ◽  
...  
Keyword(s):  
Rossby Waves ◽  
Chukchi Sea ◽  
Shelf Break ◽  
Topographic Rossby Waves

COASTAL UPWELLING AT TERENGGANU AND PAHANG COASTAL WATERS: INTERACTION OF HYDROGRAPHY, CURRENT CIRCULATION AND PHYTOPLANKTON BIOMASS

2016 ◽  
Vol 78 (8) ◽  
Author(s):  
Zuraini Zainol ◽  
Mohd Fadzil Mohd Akhir
Keyword(s):  
Coastal Waters ◽  
Phytoplankton Biomass ◽  
Current Flow ◽  
Coastal Upwelling ◽  
Transition Period ◽  
Southwest Monsoon ◽  
Good Evidence ◽  
Spatial And Temporal Variability ◽  
Seasonal Influence ◽  
Current Circulation

The hydrographic characteristics and current circulation in Terengganu and Pahang coastal waters were examined for their spatial and temporal variability based on the seasonal influence during the transition period (April 2014) and southwest monsoon (June and August, 2014). The results of this study demonstrated the presence of slightly cooler water during June and August, 2014 compared to April, 2014, which indicate the existence of coastal upwelling. Furthermore, the uplifting of isotherms towards the coast during the study trip was also a good evidence of upwelling. The current flow generated by the wind was the possible reason of the features. Furthermore, this study also makes the first attempt to observe the coupling effects between coastal upwelling and the phytoplankton biomass in Terengganu and Pahang coastal waters, which is still sparse. Interestingly, apart from the nutrient availability, the coastal upwelling was believed to influence the phytoplankton biomass at the study area.

Upwelling by internal tides and kelvin waves at the continental shelf break on the Great Barrier Reef

1983 ◽  
Vol 34 (1) ◽  
pp. 65 ◽  
Author(s):  
E Wolanski ◽  
GL Pickard
Keyword(s):  
Continental Shelf ◽  
Great Barrier Reef ◽  
Low Frequency ◽  
Kelvin Waves ◽  
Shelf Break ◽  
Internal Tides ◽  
Wind Component ◽  
Barrier Reef ◽  
Tidal Period ◽  
Continental Shelf Break

A time series of 50 days duration was obtained of sea levels and winds and of temperature and currents at six depths from 27 to 104 m at 18�19'S.,147�21'E. on the continental shelf break between the Great Barrier Reef and the Coral Sea. The sea-level signal had a predominantly mixed solar and lunar semidiurnal tidal period. The currents consisted of a semidiurnal tidal component oriented primarily cross-shelf, except near the sea floor, superimposed on a low-frequency, predominantly longshore, southward component, coherent with depth, in geostrophic balance, and modulated by the longshore wind component Large fluctuations in temperature were observed, consisting of a low-frequency component, possibly generated by internal Kelvin waves, and iiucruarions of predominantiy solar semidiurnai iidai period. The latter fiiictuations are interpreted as evidence of internal tides of amplitude up to 110 m that may be generated by the interaction of the longshore currents with topographic irregularities in the shelf. It is suggested that, during any long-term studies of water properties near the shelf break, some additional monitoring of short-term temporal variations should be carried out to avoid data aliasing by internal tides. The bottom boundary layer appears to be very active in vertical mixing. Internal tides may be very important in introducing other water components, e.g. nutrients, to the outer Great Barrier Reef.

Internal tides and sediment transport at the shelf break in the Celtic Sea

1987 ◽  
Vol 7 (5) ◽  
pp. 485-517 ◽  
Author(s):  
A.D. Heathershaw ◽  
A.L. New ◽  
P.D. Edwards
Keyword(s):  
Sediment Transport ◽  
Shelf Break ◽  
Internal Tides ◽  
Celtic Sea

Increased utility of the Secchi disk to assess eutrophication in coastal waters with freshwater run-off

2006 ◽  
Vol 60 (1-2) ◽  
pp. 19-29 ◽  
Author(s):  
Carina P. Erlandsson ◽  
Anders Stigebrandt
Keyword(s):  
Coastal Waters ◽  
Secchi Disk ◽  
Run Off
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