scholarly journals Tidal generation of large sub-mesoscale eddy dipoles

Ocean Science ◽  
2011 ◽  
Vol 7 (4) ◽  
pp. 487-502 ◽  
Author(s):  
W. Callendar ◽  
J. M. Klymak ◽  
M. G. G. Foreman
Keyword(s):  
Potential Vorticity ◽  
Tidal Flow ◽  
Mesoscale Eddy ◽  
Haida Gwaii ◽  
Queen Charlotte Islands ◽  
Positive Vorticity ◽  
Tidal Cycles ◽  
Flow Past ◽  
Eddy Generation ◽  
Haida Eddies

Abstract. Numerical simulations of tidal flow past Cape St. James on the south tip of Haida Gwaii (Queen Charlotte Islands) are presented that indicate mesoscale dipoles are formed from coalescing tidal eddies. Observations in this region demonstrate robust eddy generation at the Cape, with the primary process being flow separation of buoyant or wind driven outflows forming large anti-cyclonic, negative potential vorticity, Haida Eddies. However, there are other times where dipoles are observed in satellites, indicating a source of positive potential vorticity must also be present. The simulations here build on previous work that implicates oscillating tidal flow past the cape in creating the positive vorticity. Small headland eddies of alternating vorticity are created each tide. During certain tidal cycles, the headland eddies coalesce and self organize in such a way as to create large >20-km diameter eddies that then self-advect into deep water. The self advection speed is faster than the beta drift of anti-cyclones, and the propagation direction appears to be more southerly than typical Haida Eddies, though the model contains no mean wind-driven flows. These eddies are smaller than Haida Eddies, but given their tidal origin, may represent a more consistent source of coastal water that is injected into the interior of the subpolar gyre.

scholarly journals Tidal generation of large sub-mesoscale eddy dipoles

2011 ◽  
Vol 8 (2) ◽  
pp. 723-760
Author(s):  
W. Callendar ◽  
J. M. Klymak ◽  
M. G. G. Foreman
Keyword(s):  
Potential Vorticity ◽  
Tidal Flow ◽  
Mesoscale Eddy ◽  
Positive Potential ◽  
Queen Charlotte Islands ◽  
Positive Vorticity ◽  
Tidal Cycles ◽  
Flow Past ◽  
Eddy Generation ◽  
Haida Eddies

Abstract. Numerical simulations of tidal flow past Cape St. James on the south tip of Haida Gwai (Queen Charlotte Islands) are presented that indicate mesoscale dipoles are formed from coalescing tidal eddies. Observations in this region demonstrate robust eddy generation at the Cape, with the primary process being flow separation of buoyant or wind driven outflows forming large anti-cyclonic, negative potential vorticity, Haida Eddies. However, there are other times where dipoles are observed in satellites, indicating a source of positive potential vorticity must also be present. The simulations here build on previous work that implicates oscillating tidal flow past the cape in creating the positive vorticity. Small headland eddies of alternating vorticity are created each tide. During certain tidal cycles, the headland eddies coalesce and self organize in such a way as to create large >20-km diameter eddies that then self-advect into deep water. The self advection speed is faster than the beta drift of anti-cyclones, and the propagation direction appears to be more southerly than typical Haida Eddies, though the model contains no mean wind-driven flows. These eddies are smaller than Haida Eddies, but given their tidal origin, may represent a more consistent source of coastal water that is injected into to the interior of the subpolar gyre.

Using reflection seismic method to estimate the fluid dynamics parameters related to wakes

2021 ◽  
Author(s):  
Wenhao Fan ◽  
Haibin Song ◽  
Kun Zhang ◽  
Yi Gong ◽  
Shun Yang ◽  
...  
Keyword(s):  
Potential Vorticity ◽  
Negative Potential ◽  
Distribution Area ◽  
The West ◽  
West Side ◽  
Reflection Seismic ◽  
Vorticity Distribution ◽  
Positive Vorticity ◽  
Coherent Vortices ◽  
Survey Line

<p>In this study, when using reflection seismic data to study the wakes of the Batan Islands, a method for estimating the fluid dynamics parameters such as the relative vorticity (relative Rossby number) and the relative potential vorticity is proposed. Although the relative Rossby number estimation method proposed in this study cannot guarantee absolute accuracy in the calculation value, this method is more accurate in describing the positive and negative vorticity distribution for the wakes, and the resolution of the positive and negative vorticity distribution described by this method is higher than the result of the reanalysis data. For the wakes developed in the Batan Islands, the reflection events in the wake development area have the larger inclination than the reflection events in the western Pacific water distribution area. It is also found that the negative vorticity wakes are mainly distributed on the west side of the island/ridge, and the positive vorticity wakes are mainly distributed on the east side of the island/ridge. This is consistent with the understanding of previous wakes simulations. The strong vorticity values in the study area are mainly distributed at depths above 300m, and the maximum impact depth of wakes can reach 600m. At the downstream position of the wake on the survey line 7, it can be seen that the bottom boundary layer has separated, and there is the negative vorticity wakes on the west side intruding into the positive vorticity wakes on the east side , which is presumed to be caused by the disturbance of the small anticyclone existing near the Batan Islands. For the survey line 7, the negative potential vorticity is mainly distributed on the west side of the island/ridge, and the influence range can reach the sea depth of 600m. In the negative potential vorticity region, there is strong energy dissipation and vertical shear. In this study, we don’t find the existence of submesoscale coherent vortices on the survey line 7, but find the reflection structure similar to filaments on the seismic section. Combined with the analysis of the balanced Richardson number angle of survey line 7, we speculate that the wake in the negative potential vorticity distribution area has the characteristics of symmetrical instability, and the symmetrical instability may destroy the process of filaments forming submesoscale coherent vortices.</p>

Preliminary investigation of a late Wisconsinan fauna from K1 cave, Queen Charlotte Islands (Haida Gwaii), Canada

2004 ◽  
Vol 62 (1) ◽  
pp. 105-109 ◽  
Author(s):  
Carolyn L. Ramsey ◽  
Paul A. Griffiths ◽  
Daryl W. Fedje ◽  
Rebecca J. Wigen ◽  
Quentin Mackie
Keyword(s):  
Late Pleistocene ◽  
Environmental Conditions ◽  
Preliminary Investigation ◽  
Skeletal Remains ◽  
Human Migration ◽  
Early Holocene ◽  
Haida Gwaii ◽  
Queen Charlotte Islands ◽  
Late Wisconsinan ◽  
Early Human

Recent investigations of a limestone solution cave on the Queen Charlotte Islands (Haida Gwaii) have yielded skeletal remains of fauna including late Pleistocene and early Holocene bears, one specimen of which dates to ca. 14,400 14C yr B.P. This new fossil evidence sheds light on early postglacial environmental conditions in this archipelago, with implications for the timing of early human migration into the Americas.

scholarly journals Subsurface Mesoscale Eddy Generation in the Ocean off Central Chile

2019 ◽  
Vol 124 (8) ◽  
pp. 5700-5722 ◽  
Author(s):  
Marcela Contreras ◽  
Oscar Pizarro ◽  
Boris Dewitte ◽  
Hector H. Sepulveda ◽  
Lionel Renault
Keyword(s):  
Mesoscale Eddy ◽  
Central Chile ◽  
Eddy Generation

New and little-known marine species of Pinaciophora, Rabdiaster and Thomseniophora gen. nov. (Rotosphaerida: Pompholyxophryidae)

2012 ◽  
Vol 93 (5) ◽  
pp. 1211-1229 ◽  
Author(s):  
Kenneth H. Nicholls
Keyword(s):  
Pacific Ocean ◽  
New Genus ◽  
Marine Species ◽  
Single Type ◽  
Haida Gwaii ◽  
Western Atlantic ◽  
Queen Charlotte Islands ◽  
Marine Habitats ◽  
Near Shore ◽  
One New Species

Near-shore benthic sediment samples collected at low tide from the western Atlantic Ocean (Sable Island, Nova Scotia, Canada) and the eastern Pacific Ocean (Haida Gwaii (Queen Charlotte Islands), British Columbia, Canada) were searched for little-known species of the rhizarian (Cercozoa) genera Pinaciophora, Rabdiaster and other related rotosphaerids. Several representatives with complete investitures of silica-scales (the structure of which is taxonomically diagnostic) were studied by transmission and scanning electron microscopy. The validity of the genus Pinaciophora (sensu Penard, 1904) as defined by a single type of plate-scale only, was strengthened by the discovery of Pinaciophora rubicunda and of another previously undescribed entity, both of which lacked spine-scales. Several earlier reports of loose scales from marine habitats, and erroneously identified as the freshwater P. fluviatilis, might be assigned to P. marina sp. nov. The new genus Thomseniophora was erected to include all ‘Pinaciophora' previously known to produce spine-scales and seven new taxa were described. Six other little-known species of Thomseniophora, Pinaciophora and Rabdiaster were described from the Canadian west coast (Pacific Ocean) including one new species of Pinaciophora. The addition of Thomseniophora brings the number of genera assigned to the Rotosphaerida to six: Pinaciophora, Thomseniophora, Rabdiaster, Rabdiophrys and Pompholyxophrys. The presence of several apparently closely related taxa in the same collection (same location and sampling date) strengthens the conclusion that relatively small differences in the morphology of their siliceous scales were more likely caused by genetic differences than by environmental influences.

On the land mammals of the Queen Charlotte Islands, British Columbia, by John Henry Keen, with a catalogue of specimens

2017 ◽  
Vol 44 (2) ◽  
pp. 259-274 ◽  
Author(s):  
S. G. Sealy
Keyword(s):  
British Columbia ◽  
Natural History ◽  
The United States ◽  
Haida Gwaii ◽  
North Central ◽  
Queen Charlotte Islands ◽  
The North ◽  
Annotated List ◽  
History Of ◽  
Evolution Of Mammals

From 1890 to 1899, the Reverend John Henry Keen collected plants and animals in the vicinity of the Anglican mission at Massett, on the north-central coast of the Queen Charlotte Islands (Haida Gwaii), British Columbia, Canada. Keen's prodigious collecting efforts resulted in the first detailed information on the natural history of that region, particularly of the beetle fauna. Keen also observed and collected mammals, depositing specimens in museums in Canada, England and the United States, for which a catalogue is given. Several mammal specimens provided the basis for new distributional records and nine new taxa, two of which were named for Keen. In 1897, Keen prepared an annotated list of ten taxa of land mammals of the Queen Charlotte Islands, including the first observations of natural history for some of the species. Particularly important were the insightful questions Keen raised about the evolution of mammals isolated on the Islands, especially why certain species, abundant on the mainland, were absent.

scholarly journals Lichen Zonation on Coastal Rocks in Gwaii Haanas National Park Reserve, Haida Gwaii (Queen Charlotte Islands), British Columbia

2004 ◽  
Vol 118 (3) ◽  
pp. 405 ◽  
Author(s):  
Irwin M. Brodo ◽  
Norm A. Sloan
Keyword(s):  
British Columbia ◽  
National Park ◽  
Lichen Species ◽  
Rocky Shores ◽  
Haida Gwaii ◽  
Queen Charlotte Islands ◽  
Heritage Site ◽  
White Band ◽  
Black Band ◽  
First Time

The occurrence of 43 marine lichen species on intertidal rocky shores of southern Haida Gwaii (Queen Charlotte Islands), British Columbia is described and related particularly to elevation on the shore (duration of seawater immersion) and exposure to waves. In the area of Gwaii Haanas National Park Reserve and Haida Heritage Site on Moresby Island, rockdwelling marine lichens are distributed in zones much as they are elsewhere in the world, although some species found abundantly only in Haida Gwaii give the local shores a unique appearance. In common with other areas, there is a conspicuous black band of Verrucaria species (in this case, nine species plus other black lichens) at the upper edge of the intertidal zone. A conspicuous white band of Coccotrema maritimum above the black band is a unique feature of this flora. The unusually large percentage of endemic, near-endemic or disjunct lichen species and their phytogeography suggest that at least the headland rocks along the west coast were refugia during the last glacial maximum. Verrucaria striatula and V. sandstedei are reported for the first time from British Columbia. Erratum for figure included.

scholarly journals Sea Otter, Enhydra lutris, Sightings off Haida Gwaii / Queen Charlotte Islands, British Columbia, 1972-2002

2004 ◽  
Vol 118 (2) ◽  
pp. 270
Author(s):  
Kimberly Raum-Suryan ◽  
Kenneth Pitcher ◽  
Richard Lamy
Keyword(s):  
British Columbia ◽  
Steller Sea Lion ◽  
Sea Otter ◽  
Eumetopias Jubatus ◽  
Enhydra Lutris ◽  
Haida Gwaii ◽  
Sea Lion ◽  
Sea Otters ◽  
The Past ◽  
Queen Charlotte Islands

On 27 June 2001 we observed and photographed a Sea Otter (Enhydra lutris) adjacent to a Steller Sea Lion (Eumetopias jubatus) haulout near Sgang Gwaay (Anthony Island), Haida Gwaii / Queen Charlotte Islands. This is one of only eight documented sightings of Sea Otters in these waters during the past 30 years. These sightings may represent the beginning of the expansion of Sea Otters to their former range off Haida Gwaii.

scholarly journals Landslide response to the 27 October 2012 earthquake (MW 7.8), southern Haida Gwaii, British Columbia, Canada

Landslides ◽  
2019 ◽  
Vol 17 (3) ◽  
pp. 517-526 ◽  
Author(s):  
Sophia Barth ◽  
Marten Geertsema ◽  
Alexandre R. Bevington ◽  
Alison L. Bird ◽  
John J. Clague ◽  
...  
Keyword(s):  
British Columbia ◽  
Timber Harvesting ◽  
Haida Gwaii ◽  
Annual Average ◽  
Landslide Occurrence ◽  
Road Building ◽  
Average Area ◽  
Queen Charlotte Islands ◽  
Southern Half

Abstract In this paper, we examine the influence of the 27 October 2012, Mw 7.8 earthquake on landslide occurrence in the southern half of Haida Gwaii (formerly Queen Charlotte Islands), British Columbia, Canada. Our 1350 km2 study area is undisturbed, primarily forested terrain that has not experienced road building or timber harvesting. Our inventory of landslide polygons is based on optical airborne and spaceborne images acquired between 2007 and 2018, from which we extracted and mapped 446 individual landslides (an average of 33 landslides per 100 km2). The landslide rate in years without major earthquakes averages 19.4 per year, or 1.4/100 km2/year, and the annual average area covered by non-seismically triggered landslides is 35 ha/year. The number of landslides identified in imagery closely following the 2012 earthquake, and probably triggered by it, is 244 or an average of about 18 landslides per 100 km2. These landslides cover a total area of 461 ha. In the following years—2013–2016 and 2016–2018—the number of landslides fell, respectively, to 26 and 13.5 landslides per year. In non-earthquake years, most landslides happen on south-facing slopes, facing the prevailing winds. In contrast, during or immediately after the earthquake, up to 32% of the landslides occurred on north and northwest-facing slopes. Although we could not find imagery from the day after the earthquake, overview reconnaissance flights 10 and 16 days later showed that most of the landslides were recent, suggesting they were co-seismic.

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