THE GEOMAGNETIC LATITUDE EFFECT ON THE NUCLEON AND MESON COMPONENT OF COSMIC RAYS AT SEA LEVEL

1956 ◽  
Vol 34 (1) ◽  
pp. 1-19 ◽  
Author(s):  
D. C. Rose ◽  
J. Katzman
Keyword(s):  
Cosmic Rays ◽  
Sea Level ◽  
North American ◽  
Geomagnetic Latitude ◽  
Vertical Direction ◽  
Temperature Correction ◽  
The Arctic ◽  
High Latitudes ◽  
Primary Spectrum ◽  
The North

Measurements have been taken on the changes in intensity of the nucleon and meson components of cosmic rays during a cruise of the Canadian Naval Icebreaker Labrador into the Arctic, through the North West Passage, and circumnavigating the North American Continent. The geomagnetic latitudes covered extend from 18°N. to 89°N. The latitude knee is clearly shown at a geomagnetic latitude of about 52° in the case of the nucleon component and less definitely between 40° and 50° in the case of the meson component. The rigidity of particles arriving in a vertical direction at 52° is 2.1 Bv. and at 45° is 3.7 Bv. Meyer and Simpson have shown that changes in the primary spectrum between 1948 and 1954 probably extend up to these rigidities and such changes should, therefore, be observable at sea level. The longitude effect at low latitudes is clearly shown by differences in intensity between the measurements on the east and west sides of North America. In the case of the meson component, the magnitude of the longitude effect at these longitudes was found to be greater than that shown by Millikan and Neher in 1936. The interpretation of the meson component results above the knee is complicated by difficulties in temperature correction. In the case of the nucleon component, an apparent longitude effect exists above the knee in that there was a small difference in the intensity at high latitudes in the eastern and western parts of the North American Arctic. No satisfactory explanation is offered for this. The diurnal variation of the nucleon component at high latitudes is shown but no unusual features were found. Appreciation is expressed to the Royal Canadian Navy for making these measurements possible.

scholarly journals Atmospheric electricity in high latitudes

1905 ◽  
Vol 76 (508) ◽  
pp. 160-164 ◽  
Keyword(s):  
Recent Work ◽  
Sea Level ◽  
Daily Variation ◽  
Atmospheric Electricity ◽  
Potential Gradient ◽  
The Arctic ◽  
High Latitudes ◽  
The North ◽  
Arctic Regions ◽  
The Earth

The recent work of Elster and Geitel, Ebert and others, has added three new factors to the data for the study of atmospheric electricity, namely:— The rate at which the permanent charge on the surface of the earth is being dissipated into the atmosphere, the state of ionization of the air, and the amount of radio-active emanation in the lower regions of the atmosphere. These three factors have been carefully studied in the temperate zone. With the idea of extending our knowledge of them into the Arctic regions, I was granted permission by the Commissioners of the 1851 Exhibition Scholarship to undertake a year’s work in the Lapp village of Karasjok (69° 17' N.; 25° 35' E.; 129 metres above sea level, and about 200 miles south of the North Cape), The work undertaken consisted of the following:- 1. By means of a Benndorf self-registering electrometer to obtain daily curves of the potential gradient, and from these to calculate the yearly and daily variation. 2. To make systematic observations of the dissipation by means of Elster and Geitel’s instrument. 3. To make corresponding measurements of the ionization with Ebert’s apparatus. 4. To measure the amount of radio-active emanation in the atmosphere. 5. To investigate, as far as possible, the influence of the aurora on the electrical conditions of the atmosphere.

A new fossil occurrence from the Vendom Fiord Formation (type area), Ellesmere Island

1978 ◽  
Vol 15 (10) ◽  
pp. 1675-1679 ◽  
Author(s):  
D. G. Perry
Keyword(s):  
Sea Level ◽  
North American ◽  
Ellesmere Island ◽  
The Arctic ◽  
Early Devonian ◽  
The North ◽  
Type Area ◽  
Formation Type ◽  
Devonian Age

Probable reworked Lochkovian (early Early Devonian) brachiopods and conodonts were recovered from the basal clastic beds of the Vendom Fiord Formation in the type area on central Ellesmere Island. Although most of the fossils are reworked from underlying strata, none appear to be younger than Lochkovian. Data obtained by other workers from more northerly exposures of the Vendom Fiord Formation show that the lower part of the formation is no older than late Pragian (middle Early Devonian). Elsewhere, the North American Early Devonian eustatic sea-level minimum occurs in the Pragian and is followed by transgressive deposits of late Early Devonian age of which the Vendom Fiord Formation possibly represents the basal transgressive unit in the Arctic Archipelago.

scholarly journals Carbon cycling in the North American coastal ocean: A synthesis

2018 ◽  
Author(s):  
Katja Fennel ◽  
Simone Alin ◽  
Leticia Barbero ◽  
Wiley Evans ◽  
Timotheé Bourgeois ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
North American ◽  
Inorganic Carbon ◽  
Co2 Flux ◽  
Carbon Fluxes ◽  
Coastal Ocean ◽  
Open Ocean ◽  
The Arctic ◽  
The North ◽  
Anthropogenic Carbon

Abstract. A quantification of carbon fluxes in the coastal ocean and across its boundaries, specifically the air-sea, land-to-coastal-ocean and coastal-to-open-ocean interfaces, is important for assessing the current state and projecting future trends in ocean carbon uptake and coastal ocean acidification, but is currently a missing component of global carbon budgeting. This synthesis reviews recent progress in characterizing these carbon fluxes with focus on the North American coastal ocean. Several observing networks and high-resolution regional models are now available. Recent efforts have focused primarily on quantifying net air-sea exchange of carbon dioxide (CO2). Some studies have estimated other key fluxes, such as the exchange of organic and inorganic carbon between shelves and the open ocean. Available estimates of air-sea CO2 flux, informed by more than a decade of observations, indicate that the North American margins act as a net sink for atmospheric CO2. This net uptake is driven primarily by the high-latitude regions. The estimated magnitude of the net flux is 160 ± 80 Tg C/y for the North American Exclusive Economic Zone, a number that is not well constrained. The increasing concentration of inorganic carbon in coastal and open-ocean waters leads to ocean acidification. As a result conditions favouring dissolution of calcium carbonate occur regularly in subsurface coastal waters in the Arctic, which are naturally prone to low pH, and the North Pacific, where upwelling of deep, carbon-rich waters has intensified and, in combination with the uptake of anthropogenic carbon, leads to low seawater pH and aragonite saturation states during the upwelling season. Expanded monitoring and extension of existing model capabilities are required to provide more reliable coastal carbon budgets, projections of future states of the coastal ocean, and quantification of anthropogenic carbon contributions.

Revision of Tenticospirifer Tien, 1938, and similar spiriferid brachiopod genera from the Late Devonian (Frasnian) of Eurasia, North America, and Australia

2000 ◽  
Vol 74 (3) ◽  
pp. 444-463 ◽  
Author(s):  
Xueping Ma ◽  
Jed Day
Keyword(s):  
North America ◽  
Sea Level ◽  
South China ◽  
North American ◽  
Type Species ◽  
Western Europe ◽  
Late Devonian ◽  
Carbonate Platforms ◽  
The North ◽  
New Family

The cyrtospiriferid brachiopod genus Tenticospirifer Tien, 1938, is revised based on restudy of the type species from the Frasnian (Late Devonian) of the Russian Platform. As revised the genus includes cyrtospiriferid species with pyramidal ventral valves, catacline ventral interareas, a narrow delthyrium, few sinal plications, and lack a median dorsal septum and pseudodeltidium. All species retained in the genus are of Givetian and Frasnian age. All Famennian age species described from South China and North America are rejected from the genus. It appears that Tenticospirifer evolved during the early Givetian in western Europe and remained endemic to that region during the remainder of the Givetian. Successive migrations of Tenticospirifer from eastern Laurussia to North America, then to South China and possibly Australia, coincided with middle and late Frasnian eustatic sea level rises, respectively. The North American species Spirifera cyrtinaformis Hall and Whitfield, 1872, and related species identified as Tenticospirifer by North American workers, are reassigned to Conispirifer Lyashenko, 1985. Its immigration to and widespread dispersal in carbonate platforms of western Laurussia, northern Gondwana and tropical island arcs (?) coincided with a major late Frasnian eustatic sea level rise. The new family Conispiriferidae is proposed with Conispirifer Lyashenko, 1985, selected as the type genus. The new family also includes the new genus Pyramidaspirifer with Platyrachella alta Fenton and Fenton, 1924, proposed as the type species. The affinity of the new family remains uncertain pending restudy of key genera currently included in the Superfamily Cyrtospiriferoidea. Available data from the Devonian brachiopod literature indicate that species of Pyramidaspirifer are restricted to late Frasnian deposits of central and western North America.

scholarly journals Origin of the Late Ordovician Lepidocyclus brachiopod fauna in North America and its biogeographic significance

1992 ◽  
Vol 6 ◽  
pp. 149-149
Author(s):  
Jisuo Jin
Keyword(s):  
North America ◽  
Sea Level ◽  
North American ◽  
Plate Tectonics ◽  
Late Ordovician ◽  
Sea Level Changes ◽  
Stepping Stones ◽  
Shell Size ◽  
Larval Stages ◽  
The North

Three rhynchonellid brachiopod genera, Hiscobeccus, Lepidocyclus, and Hypsiptycha, are the most diagnostic elements of the Lepidocyclus fauna of North America in Late Ordovician time. These are characterized by relatively large, strongly biconvex to globular shells with coarse imbricating growth lamellae and, internally, with septiform cardinal processes in brachial valves. Among the three genera, Hiscobeccus appears the earliest, now known from rocks of late Trentonian-Edenian age in the Canadian Rocky Mountains and Mackenzie Mountains. Morphologically, Hiscobeccus is distinguished from the other two genera by its open delthyrium in the pedicle valve. Early forms of Hiscobeccus show close morphological similarity to Rhynchotrema in their non-globular biconvex shells covered by strong growth lamellae only in the anterior portions. It has been suggested that Hiscobeccus evolved from the Rhynchotrema wisconsinense stock through increase in shell size, globosity, and strength of growth lamellae. Earliest species of Rhynchotrema has been documented convincingly from rocks of early Trentonian age, and the derivation of Hiscobeccus most likely took place during the mid-Trentonian. Lepidocyclus and Hypsiptycha evolved from either Rhynchotrema or Hiscobeccus by developing a pair of deltidial plates covering the delthyrium.Rhynchotrema and other rhynchonellids that evolved before mid-Trentonian time are common to the North American (Laurentian) and the Siberia-Kazakhstan paleocontinents. In contrast, Hiscobeccus, Lepidocyclus, and Hypsiptycha that evolved after the mid-Trentonian are virtually restricted to Laurentia. Therefore, Rhynchotrema marked the last successful intercontinental migration of rhynchonellids during their Llandeilian-Caradocian cosmopolitanism. The pronounced provincialism of the North American Lepidocyclus fauna may have been caused by a number of factors. Facies control is not likely the explanation because these rhynchonellids occur in nearly all the inland and marginal platform seas of Laurentia and commonly are found together in the same types of rocks. Plate tectonics and sea-level changes are considered major causes. The Ordovician rhynchonellids lived in shallow marine (intertidal-subtidal) environments and were incapable of crossing vast, deep oceanic barriers because of their sedentary mode of life and short-lived motile larval stages. The widening of the ocean between North America and Siberia, coupled with high sea-level stand, may have created a sufficiently wide oceanic barrier to interrupt faunal mixing between the two paleocontinents by late Trentonian time. Moreover, the rise in sea level would have resulted in the disappearance of island faunas, which could have served as stepping stones for intercontinental migration of shallow-water benthic faunas during low sea-level stand.

scholarly journals Carbon isotope (δ<sup>13</sup>C) excursions suggest times of major methane release during the last 14 kyr in Fram Strait, the deep-water gateway to the Arctic

2015 ◽  
Vol 11 (4) ◽  
pp. 669-685 ◽  
Author(s):  
C. Consolaro ◽  
T. L. Rasmussen ◽  
G. Panieri ◽  
J. Mienert ◽  
S. Bünz ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Carbon Isotope ◽  
Deep Water ◽  
Planktonic Foraminifera ◽  
Sediment Supply ◽  
The Arctic ◽  
Fram Strait ◽  
The North ◽  
Carbon Isotope Excursion

Abstract. We present results from a sediment core collected from a pockmark field on the Vestnesa Ridge (~ 80° N) in the eastern Fram Strait. This is the only deep-water gateway to the Arctic, and one of the northernmost marine gas hydrate provinces in the world. Eight 14C AMS dates reveal a detailed chronology for the last 14 ka BP. The δ 13C record measured on the benthonic foraminiferal species Cassidulina neoteretis shows two distinct intervals with negative values termed carbon isotope excursion (CIE I and CIE II, respectively). The values were as low as −4.37‰ in CIE I, correlating with the Bølling–Allerød interstadials, and as low as −3.41‰ in CIE II, correlating with the early Holocene. In the Bølling–Allerød interstadials, the planktonic foraminifera also show negative values, probably indicating secondary methane-derived authigenic precipitation affecting the foraminiferal shells. After a cleaning procedure designed to remove authigenic carbonate coatings on benthonic foraminiferal tests from this event, the 13C values are still negative (as low as −2.75‰). The CIE I and CIE II occurred during periods of ocean warming, sea-level rise and increased concentrations of methane (CH4) in the atmosphere. CIEs with similar timing have been reported from other areas in the North Atlantic, suggesting a regional event. The trigger mechanisms for such regional events remain to be determined. We speculate that sea-level rise and seabed loading due to high sediment supply in combination with increased seismic activity as a result of rapid deglaciation may have triggered the escape of significant amounts of methane to the seafloor and the water column above.

Characteristics of the Beaufort Sea High

2011 ◽  
Vol 24 (1) ◽  
pp. 159-182 ◽  
Author(s):  
Mark C. Serreze ◽  
Andrew P. Barrett
Keyword(s):  
Sea Level ◽  
North American ◽  
Wave Train ◽  
Beaufort Sea ◽  
Surface Expression ◽  
Teleconnection Pattern ◽  
The Arctic ◽  
Positive Phase ◽  
Tropospheric Temperature ◽  
Surface Winds

Abstract Characteristics of the Arctic Ocean’s Beaufort Sea high are examined using fields from the NCEP–NCAR reanalysis. At a 2-hPa contour interval, the Beaufort Sea high appears as a closed anticyclone in the long-term annual mean sea level pressure field and in spring. In winter, the Beaufort Sea region is influenced by a pressure ridge at sea level extending from the Siberian high to the Yukon high over northwestern Canada. As assessed from 6-hourly surface winds, the mean frequency of anticyclonic surface winds over the Beaufort Sea region is fairly constant through the year. While for all seasons a strong closed high can be interpreted as the surface expression of an amplified western North American ridge at 500 hPa, there is some suggestion of a split flow, where the ridge linked to the surface high is separated from the ridge to the south that lies within the main belt of westerlies. The Aleutian low in the North Pacific tends to be deeper than normal when there is a strong Beaufort Sea high. In all seasons but autumn, a strong Beaufort Sea high is associated with positive lower-tropospheric temperature anomalies covering much of the Arctic Ocean; positive anomalies are especially pronounced in spring. Seasons with a weak anticyclone show broadly opposing anomalies. A strong high is found to be a feature of the negative phase of the summer northern annular mode, the positive phase of the Pacific–North American wave train, and, to a weaker extent, the positive phase of the summer Arctic dipole anomaly and Pacific decadal oscillation. The unifying theme is that, to varying degrees, the high-latitude 500-hPa ridge associated with the Beaufort Sea high represents a center of action in each teleconnection pattern.

The Arctic Institute of North America

Polar Record ◽  
1956 ◽  
Vol 8 (52) ◽  
pp. 22-23 ◽  
Author(s):  
P. D. Baird
Keyword(s):  
North America ◽  
North American ◽  
Scientific Research ◽  
The Arctic ◽  
The North ◽  
Reference Information ◽  
North American Arctic ◽  
Mcgill University

The Arctic Institute of North America was established in 1945 in two small rooms in McGill University, with a staff consisting of Dr Lincoln Washburn and a secretary, who made up for the lack of equipment and facilities by abundant energy and enthusiasm. Since then the Institute's growth has been considerable, always in the direction of its three main objectives—to form a centre for reference information and study on the North American Arctic, to encourage arctic scientific research in any field, and to disseminate arctic information by means of a journal, other publications, and lectures.

scholarly journals Athapaskan migration to the North American Sout

2019 ◽  
Vol 12 ◽  
pp. 139-164
Author(s):  
Magdalena Lewandowska
Keyword(s):  
Great Plains ◽  
North American ◽  
Salt Lake ◽  
American Southwest ◽  
The Arctic ◽  
Migration Route ◽  
Historical Sources ◽  
Subarctic Region ◽  
The North ◽  
Athabaskan Language

The arrival of the ancestors of the Apaches and Navajo to the North American Southwest, the so-called Apachean migra-tion is one of the most widely discussed issues in American archeology. Since the 19th century, after connections were disco-vered between the Athabaskan language family, potential routes and directions of migration between the Arctic and Subarctic region (inhabited by the Northern Athabaskans) and the Southwest (inhabited by the Southern Athabaskans) began to be con-sidered. During the 1930s, the Edward Sapir’s linguistic research made it possible to determine that the migration flowed from north to south, but this conclusion merely sowed the seed of research on Apachean migration, which has since blossomed with archaeological discoveries from the last 20 or 30 years. Today, we are able to pinpoint what prompted the Athabaskans’ journey; we also know of cultures such as Promontory (around the Great Salt Lake) or Dismal River (Great Plains), which we associate with the presence of the Apachean people on both sides of the Rocky Mountains. Still, many questions remain unanswered, and previous hypotheses are being verified in the light of new discoveries. No less interesting proved the results of research into some auxiliary sciences of archeology: genetics and linguistics, and the analysis of historical sources and oral tradition.The following article aims to introduce the reader to the most important and recent discoveries related to the issue of Apachean migration, and present hypotheses that have recently emerged in the scientific community, both in the context of the migration route itself and arrival in the Southwest, as well as the dates associated with them.

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