Island in the Stream: Oceanography and Fisheries of the Charleston Bump

2001 ◽  
Keyword(s):  
Continental Slope ◽  
Gulf Stream ◽  
Topographic Feature ◽  
The Cross ◽  
Charleston Bump ◽  
Set Up ◽  
Stream Waters

<em>Abstract.</em>—The recurring seaward deflection of the Gulf Stream near 32°N latitude had been noticed by a number of investigators before the mid-1970s when Richard Legeckis first attributed the phenomenon to a topographic feature on the upper continental slope now known as the Charleston Bump. Since then, extensive studies have delineated many properties of the deflection and its effects on the Gulf Stream and surrounding waters including: the apparently bimodal nature of the deflection (resulting in the "strongly deflected" and "weakly deflected" states of the Gulf Stream's path near the Bump); the set up of the Charleston Gyre during strongly deflected conditions; the amplification of downstream-propagating Gulf Stream meanders in the Bump region; the meander-induced upwelling that accompanies meander propagation; and the cross-isobath exchange of shelf and Gulf Stream waters driven by the Charleston Gyre and Gulf Stream meanders. Of particular interest is the fact that there is still no unambiguous cause identified for inducing the Gulf Stream to shift from a weakly deflected path to a strongly deflected path, although several candidate mechanisms exist.

Mathematical modelling of salt purification by recrystallization. A cross-current flow model and its comparison with the countercurrent arrangement

1986 ◽  
Vol 51 (11) ◽  
pp. 2489-2501
Author(s):  
Benitto Mayrhofer ◽  
Jana Mayrhoferová ◽  
Lubomír Neužil ◽  
Jaroslav Nývlt
Keyword(s):  
Flow Model ◽  
Current Flow ◽  
Countercurrent Flow ◽  
Flow Models ◽  
Multi Stage ◽  
Stage Crystallization ◽  
The Cross ◽  
Current Flows ◽  
Set Up ◽  
Cross Current

A model is derived for a multi-stage crystallization with cross-current flows of the solution and the crystals being purified. The purity of the product is compared with that achieved in the countercurrent arrangement. A suitable function has been set up which allows the cross-current and countercurrent flow models to be compared and reduces substantially the labour of computation for the countercurrent arrangement. Using the recrystallization of KAl(SO4)2.12 H2O as an example, it is shown that, when the cross-current and countercurrent processes are operated at the same output, the countercurrent arrangement is more advantageous because its solvent consumption is lower.

scholarly journals Impact of Channel Geometry and Rotation on the Trapping of Internal Tides

2007 ◽  
Vol 37 (11) ◽  
pp. 2740-2763 ◽  
Author(s):  
Sybren Drijfhout ◽  
Leo R. M. Maas
Keyword(s):  
Continental Slope ◽  
Three Dimensional ◽  
Tidal Energy ◽  
Ocean Model ◽  
Internal Tides ◽  
Open Boundary ◽  
Kelvin Wave ◽  
Channel Geometry ◽  
Channel Slope ◽  
The Cross

Abstract The generation and propagation of internal tides has been studied with an isopycnic three-dimensional ocean model. The response of a uniformly stratified sea in a channel, which is forced by a barotropic tide on its open boundary, is considered. The tide progresses into the channel and forces internal tides over a continental slope at the other end. The channel has a length of 1200 km and a width of 191.25 km. The bottom profile has been varied. In a series of four experiments it is shown how the cross-channel geometry affects the propagation and trapping of internal tides, and the penetration scale of wave energy, away from the continental slope, is discussed. In particular it is found that a cross-channel bottom slope constrains the penetration of the internal tidal energy. Most internal waves refract toward a cross-channel plane where they are trapped. The exception is formed by edge waves that carry part of the energy away from the continental slope. In the case of rotation near the continental slope, the Poincaré waves that arise in the absence of a cross-channel slope no longer bear the characteristics of the wave attractor predicted by 2D theory, but are almost completely arrested, while the right-bound Kelvin wave preserves the 2D attractor in the cross-channel plane, which is present in the nonrotating case. The reflected, barotropic right-bound Kelvin wave acts as a secondary internal wave generator along the cross-channel slope.

Island in the Stream: Oceanography and Fisheries of the Charleston Bump

2001 ◽  
Keyword(s):  
Gulf Stream ◽  
Seasonal Changes ◽  
Distribution Patterns ◽  
Xiphias Gladius ◽  
Charleston Bump ◽  
Pelagic Fishery ◽  
Very High

<em>Abstract.</em>—The Gulf Stream off the east coasts of Florida, Georgia, and the Carolinas is one of the U. S. pelagic fishery regions in which particularly high swordfish discard rates were reported after a regulation limiting the landings of swordfish less than 25 kg whole weight went into effect in 1991. Swordfish <em> Xiphias gladius </em>fishing and catch locations from mandatory longline logbooks for the years 1991 through 1995 were used to explore the distribution patterns of swordfish discard rates in this region. Every 0.1 degree square of latitude and longitude was assigned a discard rate category (very high, moderate, low, none) for each month of the year based on the percentage of the swordfish catch that was discarded in that month over the five year period. Swordfish discard rates varied with latitude and season. The greatest seasonal changes were seen off the Carolinas where discard rates increased in the fall along with changes in fishing patterns.

Island in the Stream: Oceanography and Fisheries of the Charleston Bump

2001 ◽  
Keyword(s):  
Gulf Stream ◽  
Eddy Currents ◽  
Fish Fauna ◽  
Freshwater Discharge ◽  
Large Fish ◽  
Apparent Loss ◽  
Water Layers ◽  
Early Neogene ◽  
Charleston Bump ◽  
Polyprion Americanus

<em>Abstract.</em>—The Charleston Bump is a structural and topographic high on the northern Blake Plateau that overlies a seaward offset of the edge of continental crust. The feature causes the bottom to shoal and deflects the Gulf Stream offshore, causing an intensification of bottom currents. The area has been swept by strong currents since late Cretaceous time, but the strongest currents have occurred in the Neogene (last -25 million years). Nondepositional conditions prevail at present, but erosion of the bottom is checked where the bottom is armored by a hard surficial layer of phosphorite pavement. The phosphorite pavements were formed by re-cementation of eroded residues of phosphorite-rich sediments of early-Neogene age. In some places there are multiple pavements separated by poorly lithified sediments. Submersible observations indicate that the south, or current-facing flank of the Charleston Bump has several deep (>100 m) scour depressions, the southern flanks of which form cliffs characterized by ledges and overhangs. In other areas discrete layers of older Paleogene rocks have been partly eroded away, leaving cliff-like steps of 5 m or more relief. Conglomeratic phosphorite pavement layers up to 1 m thick armor most of the bottom. Where breached by scour, these pavements form both low-relief ledges and rock piles. These features form a reef-like environment of caves and overhangs utilized by wreckfish <em> Polyprion americanus </em>and barrelfish <em> Hyperoglyphe perciformis </em>as shelter from the current and as staging areas to prey on passing schools of squid. Wreckfish and other large fish were often localized in rugged bottom habitat, including caves and other shelter areas. We observed wreckfish darting from shelters to feed on passing schools of squid. Present and past observations, are consistent with the concept that impingement of the Gulf Stream at the Charleston Bump compresses midwater fauna from much thicker water layers, providing food for a flourishing big-fish fauna. During our dives we noted currents often exceeding 1 knot, and ranging to 2.4 knots. Evidence of fossil, manganese-iron-encrusted megaripples suggest even greater current regimes in the past. Investigation of the site of an earlier report of possible freshwater discharge failed to find any evidence of a closed sinkhole or freshwater discharge. Rather, we concluded that the apparent loss of buoyancy experienced by the submarine was probably caused by downward-directed eddy currents generated by currents sweeping across the pavement/void interface of a more than 100-m high cliff 3 km south of the reported location.

Island in the Stream: Oceanography and Fisheries of the Charleston Bump

2001 ◽  
Keyword(s):  
South Carolina ◽  
Surface Temperature ◽  
Gulf Stream ◽  
Fast Moving ◽  
Bottom Topography ◽  
Sea Surface ◽  
Time Dependent ◽  
New Method ◽  
Sea Surface Temperatures ◽  
Charleston Bump

<em>Abstract.</em>—The animation of daily composites of sea surface temperatures (SST) from a National Oceanic and Atmospheric Administration Geostationary Operational Environmental Satellite (GOES) provides a new method for the detection of dynamics at the surface of the ocean. By rapidly viewing the daily SST composites of hourly images, it is possible for the human eye to separate the fast moving residual clouds from the slowly moving SST patterns associated with ocean currents, eddies, and upwelling. Although each individual daily composite is still partly cloud covered, the rapid display provides the appearance of continuity of the SST patterns. The GOES SST animations were used during 1998 and 1999 to monitor the time dependent deflection of the Gulf Stream due to a rise in bottom topography southeast of Charleston, South Carolina, locally known as the Charleston Bump. Examples of the sea surface temperature animations of the Gulf Stream appear at the website: http:// www. goes .noaa.gov

scholarly journals A Cross-Knotted Suture Basket Technique for Large Nonmagnetic Intraocular Foreign Body Removal

2020 ◽  
Vol 2020 ◽  
pp. 1-4
Author(s):  
Jian Cao ◽  
Baihua Chen ◽  
Yun Li
Keyword(s):  
Foreign Body ◽  
Foreign Bodies ◽  
Intraocular Foreign Body ◽  
Effective Alternative ◽  
Foreign Body Removal ◽  
Novel Technique ◽  
Clinical Investigations ◽  
Vicryl Suture ◽  
The Cross ◽  
Set Up

Purpose. To report a novel technique of cross-knotted suture basket and to test its effectiveness in large nonmagnetic intraocular foreign body (IOFB) removal. Methods. A 7/0 Vicryl suture was cut in half and cross-knotted, and four ends were introduced into a 23G needle to form a basket. Pig eyes were used to set up the IOFB model, and the effectiveness of the suture basket in the removal of large nonmagnetic intraocular foreign bodies was tested. Results. Several modifications can be made to adapt to different situations. For the materials (stone, metal, glass, and wood) and shapes (irregular, spherical, and rectangle) of large IOFB tested, the cross-knotted suture basket successfully removed all kinds of IOFBs. Conclusion. The suture basket technique provides an accessible, safe, and effective alternative in large nonmagnetic IOFB removal. It can be adapted and interchangedand also worth’s further clinical investigations.

FATE OF PETROLEUM COMPONENTS IN ESTUARINE WATERS OF THE SOUTHEASTERN UNITED STATES

1977 ◽  
Vol 1977 (1) ◽  
pp. 611-616 ◽  
Author(s):  
Richard F. Lee
Keyword(s):  
Water Samples ◽  
Gulf Stream ◽  
Atlantic Coast ◽  
Low Molecular Weight ◽  
Degradation Rates ◽  
Polycyclic Aromatic ◽  
Benzene Toluene ◽  
South Atlantic Coast ◽  
Detrital Particles ◽  
Stream Waters

ABSTRACT Radiolabeled hydrocarbons and phenols were added to water samples from the Skidaway and Cooper Rivers, two estuarine rivers on the U.S. south Atlantic coast. The adsorption of hydrocarbons to particles and microbial degradation of different petroleum components were the processes studied. Alkanes, low molecular weight aromatics (benzene, toluene, naphthalene and methylnaphthalene) and phenols were rapidly degraded to 14CO2. Low degradation rates were observed for the higher weight polycyclic aromatic hydrocarbons, fluorene, anthracene, benz(a)anthracene, and benz(a)pyrene, and from 12 to 70% of these hydrocarbons were absorbed to suspended particles in the water. Radioauto graphs of particles after the addition of 3H-benz(a)pyrene and 3H-hexadecane to the water samples indicated the hydrocarbons associated with detrital particles. This detritus was composed of a mixture of clay, organic matter, plankton remains and living microbes. One area of the Cooper River had visible oil slicks and the degradation rates of added heptadecane (20 μg/l), naphthalene (30 μg/l) and methylnaphthalene (30 μg/l) were 0.4, 2.8 and 1.1 μg/I/day, respectively. In contrast, at a downstream site, where there were no visible slicks, the degradation rate of these same hydrocarbons were 0.1, 0.7 and 0.1 μg/l/day, respectively. Estuarine water had much higher hydrocarbon degradation rates than offshore and Gulf Stream waters.

The Russian Spiritual Verses on the Mother of God

2019 ◽  
pp. 182-194
Author(s):  
Richard Price
Keyword(s):  
Old Age ◽  
Literary Texts ◽  
Oral Culture ◽  
The Cross ◽  
Written Word ◽  
Set Up ◽  
Life On Earth

The Russian Spiritual Verses are a repertoire of hymns to be sung, which developed over centuries in an oral culture and were performed primarily by wandering minstrels. They are strikingly free of close adherence to the Gospels. We hear of Christ being baptized as an infant, and by his Mother. There are moving laments of the Virgin at the foot of the Cross, in which she laments that her Son will be unable to look after her in her old age, and Christ consoles her with a promise that he will set up her image in every church and pray to it himself. Other hymns attribute to the Virgin an important role in the bestowal of life on earth and at the Last Judgement. The Verses show an imagination untrammelled by literary texts and often inspired by icons rather than the written word.

scholarly journals Upper-Slope Jets and Gulf Stream Filaments Inshore of the Charleston Bump during Winter 2012

2019 ◽  
Vol 49 (6) ◽  
pp. 1423-1438 ◽  
Author(s):  
Harvey Seim ◽  
Catherine Edwards
Keyword(s):  
North America ◽  
Gulf Stream ◽  
Sea Surface ◽  
Maximum Temperature ◽  
Surface Mixed Layer ◽  
Time Period ◽  
Charleston Bump ◽  
Shelf Flow ◽  
Strong Curvature ◽  
Upper Slope

AbstractA 3-month-long field program conducted in winter 2012 inshore of the seaward deflection of the Gulf Stream at the Charleston Bump observed several 7–21-day periods of strong (>0.5 m s−1) equatorward along-shelf flow over the upper continental slope. In sea surface temperature images, these phenomena resemble and appear linked to warm filaments, features known to be associated with meanders of the Gulf Stream as it traverses the southeast coast of North America. However, the character of these upper-slope features differs from previous descriptions of filaments, hence we describe them as “upper-slope jets.” We document the characteristics of the jets, which are approximately 30 km in width, centered on the 200-m isobath, with a maximum temperature variation at depth, and reasonably long-lived. Southwestward flow within the jet extends to 200 m and is in approximate thermal wind balance below a surface mixed layer. Maximum transport is estimated to be about 2.0 Sv (1 Sv ≡ 106 m3 s−1), driving a net equatorward along-shelf velocity over the deployment period. For this time period, at least, the jets form the equatorward flow of the shoreward flank of the Charleston Gyre. We suggest the features resemble the Pinocchio’s Nose Intrusion recently described by Zhang and Gawarkiewicz. Large-amplitude meander crests with sufficiently strong curvature vorticity are a plausible source of initiation of the upper-slope jets.

Sign in / Sign up

Export Citation Format

Share Document