scholarly journals Landfast Ice Mapping Using MODIS Clear-Sky Composites: Application for the Banks Island Coastline in Beaufort Sea and Comparison with Canadian Ice Service Data

2021 ◽  
pp. 1-16
Author(s):  
Alexander P. Trishchenko ◽  
Yi Luo
Keyword(s):  
Beaufort Sea ◽  
Clear Sky ◽  
Banks Island ◽  
Landfast Ice ◽  
Service Data

scholarly journals Landfast ice properties over the Beaufort Sea region in 2000-2019 from MODIS and Canadian Ice Service data

2021 ◽  
Author(s):  
Alexander P. Trishchenko ◽  
Vladimir Kostylev ◽  
Yi Luo ◽  
Calin Ungureanu ◽  
Dustin Whalen ◽  
...  
Keyword(s):  
Satellite Data ◽  
Satellite Image ◽  
Beaufort Sea ◽  
Spatial Extent ◽  
General Tendency ◽  
Landfast Ice ◽  
Moderate Resolution ◽  
Break Up ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Service Data

Two decades (2000-2019) of the landfast ice properties in the Beaufort Sea region in the Canadian Arctic were analyzed at 250-m spatial resolution from two sources: 1) monthly maps derived at the Canada Centre for Remote Sensing from the Moderate Resolution Imaging Spectroradiometer clear-sky satellite image composites; 2) Canadian Ice Service charts. Detailed comparisons have been conducted for the landfast ice spatial extent, the water depth at and the distance to the outer seaward edge from the coast in four sub-regions: 1) Alaska coast; 2) Barter Island to Herschel Island; 3) Mackenzie Bay; 4) Richards Island to Cape Bathurst. The results from both sources demonstrate good agreement. The average spatial extent for the entire region over the April-June period is 48.5 (±5.0)×10<sup>3</sup> km<sup>2</sup> from Canadian Ice Service data vs 45.1 (±6.1)×10<sup>3</sup> km<sup>2</sup> from satellite data used in this study (7.0% difference). The correlation coefficient for April-June is 0.73 (p = 2.91×10<sup>-4</sup>). The long term linear trends of the April-June spatial extent since 2000 demonstrated statistically significant decline: -4.45 (±1.69)×10<sup>3</sup> km<sup>2</sup>/decade and -4.73 (±2.17)×10<sup>3</sup> km<sup>2</sup>/decade from Canadian Ice Service and satellite data respectively. The landfast ice in the Beaufort Sea region showed the general tendency for an earlier break-up, later onset and longer ice-free period. The break-up date has decreased by 7.6 days/decade in the Mackenzie Bay region. The western part of the study area did not demonstrate statistically significant changes since 2000.

Circulation and water properties in the landfast ice zone of the Alaskan Beaufort Sea

2017 ◽  
Vol 148 ◽  
pp. 185-198 ◽  
Author(s):  
Thomas J. Weingartner ◽  
Seth L. Danielson ◽  
Rachel A. Potter ◽  
John H. Trefry ◽  
Andy Mahoney ◽  
...  
Keyword(s):  
Beaufort Sea ◽  
Water Properties ◽  
Landfast Ice

Factors influencing local abundance and haulout behaviour of ringed seals (Phoca hispida) on landfast ice of the Alaskan Beaufort Sea

2002 ◽  
Vol 80 (11) ◽  
pp. 1900-1917 ◽  
Author(s):  
Valerie D Moulton ◽  
W John Richardson ◽  
Trent L McDonald ◽  
Robert E Elliott ◽  
Michael T Williams
Keyword(s):  
Beaufort Sea ◽  
Time Of Day ◽  
Intermediate Water ◽  
Phoca Hispida ◽  
Weather Factors ◽  
Industrial Activity ◽  
Ringed Seals ◽  
Landfast Ice ◽  
Local Abundance ◽  
Water Depths

This study investigates how the local abundance of ringed seals (Phoca hispida) on landfast ice of the central Alaskan Beaufort Sea is related to habitat factors and how the haulout behaviour of seals is influenced by temporal and weather factors. An understanding of these relationships is required before the potential impacts of industrial activity on ringed seals can be assessed. Intensive and replicated aerial surveys employing strip transect methodology were conducted during the springs of 1997–1999. Data were examined with χ2 tests and Poisson regression. The overall observed densities of ringed seals over water depths >3 m was 0.43, 0.39, and 0.63 seals/km2 in 1997–1999, respectively. Significantly more seals occurred over intermediate water depths, especially 10–20 m. In all years, seals were widely distributed on the landfast ice, but during breakup, higher numbers of seals occurred near the ice edge. Densities were significantly lower in areas with high ice deformation and extensive melt water. There was no consistent relationship between seal sightings and time of day within the 10:00–18:00 period with surveys. The peak period of haulout occurred around 1 and 2 June. Significantly more ringed seals were observed on warm, cloudy days. There was no indication that limited winter industrial activity, including ice roads and Vibroseis, occurring within the study area in 1997–1999 significantly affected ringed seal density in spring.

Nearshore Geohazards in the Southern Beaufort Sea, Canada

2008 ◽  
Author(s):  
Steven M. Solomon ◽  
Donald F. Forbes ◽  
Paul Fraser ◽  
Brian Moorman ◽  
Christopher W. Stevens ◽  
...  
Keyword(s):  
Water Depth ◽  
Beaufort Sea ◽  
Sidescan Sonar ◽  
Scour Depth ◽  
Mackenzie Delta ◽  
Delta Area ◽  
Drainage Patterns ◽  
Ice Surface ◽  
Landfast Ice ◽  
Ground Penetrating

Proposed development of a gas pipeline southward from the Mackenzie Delta and the presence of known accumulations of gas and oil in the southern Beaufort Sea suggest that construction of pipelines and associated infrastructure in the nearshore are likely to be proposed in the future. Recent surveys undertaken by Natural Resources Canada and its partners have focused on the shallow, poorly mapped nearshore region of the Mackenzie Delta (&lt;6 m water depth) that extends ∼50 km offshore and lies largely within the landfast ice zone. Ice-keel scouring, strudel scour and nearsurface ice-bonding are being investigated. High resolution sidescan sonar and multibeam bathymetry systems were used to map the seabed over three consecutive years and show that ice keel scouring of the seabed is extensive. The maximum scour depth measured was 0.6 m in 6 m water depth with an average scour depth of 0.2 m. The same scours were visible in repeat surveys indicating that sedimentation was sufficiently low during the study, so that the scours were not infilled. Strudel drainage and associated seabed scour occurs when spring-melt river water overflows onto the surface of the landfast and bottomfast ice once discharge exceeds under-ice channel capacity, then drains back through the floating landfast ice via cracks and holes. Although common offshore of small deltas on the Alaska and Yukon coast, these features were first documented in the Mackenzie Delta area during field surveys in 2006 and 2007 that revealed strudel drainage (radial drainage patterns) features on the ice surface. A total of three strudel scours were later identified using swath-survey equipment in 1.2 m of water. The largest scour was 20 m wide with a maximum depth of 0.8 m below the surrounding seabed. Extensive surveys in Alaska have identified strudel scours exceeding 3 m below the seabed. Nearsurface ice-bonding and permafrost are known to occur in shallow water where sea ice freezes to the seabed. A combination of Synthetic Aperture Radar (SAR), ground penetrating radar (GPR) and multi-year ground temperature measurements have been used to map the horizontal and vertical extent of nearsurface ice bonding in extensive shoals found off the front of the Mackenzie Delta. In the shallowest water depths permafrost extends to 22 m below the seabed with an active layer of less than 1.2 m. In deeper water, permafrost disappears but seasonal frost can form in the upper 2–3 m of the seabed.

Measurements of ridge sails in the Beaufort Sea

1989 ◽  
Vol 16 (1) ◽  
pp. 16-21 ◽  
Author(s):  
M. Sayed ◽  
R. M. W. Frederking
Keyword(s):  
Sea Ice ◽  
Key Words ◽  
Geographical Distribution ◽  
Cross Section ◽  
Beaufort Sea ◽  
Outer Edge ◽  
Statistical Distributions ◽  
Landfast Ice ◽  
Ice Pressure ◽  
Block Dimensions

Ice pressure ridges in the southern Beaufort Sea near Tuktoyaktuk were surveyed in April 1986. Sail cross-section profiles and ice-block dimensions of ridges of extreme heights were measured at several locations along the outer edge of the landfast ice. Statistical distributions of sail heights as well as correlations between sail dimensions and between ice block dimensions are obtained. Geographical distribution of sail dimensions and longitudinal changes along individual ridges are examined. Key words: ridges, landfast ice, sea ice, ridge sails, ridge statistics, Beaufort Sea.

On a Collection of Polychaetous Annelids from Northern Banks Island, from the South Beaufort Sea, and from Northwest Alaska; Together with some New Records from the East Coast of Canada

1956 ◽  
Vol 13 (2) ◽  
pp. 233-246 ◽  
Author(s):  
E. Berkeley ◽  
C. Berkeley
Keyword(s):  
North America ◽  
East Coast ◽  
New Records ◽  
Canadian Arctic ◽  
Beaufort Sea ◽  
The South ◽  
Banks Island ◽  
European Arctic ◽  
East And West

Thirty-seven species of Polychaeta from the western Canadian arctic and northwest Alaska, 27 of which are new to these regions, are enumerated and discussed. Comparison is made with their records in the American arctic to the east of these regions, in the European arctic, and on the east and west coasts of North America. Six species new to the east coast of Canada are also recorded.

STRUCTURE OF THE BEAUFORT SEA CONTINENTAL MARGIN

Geophysics ◽  
1970 ◽  
Vol 35 (5) ◽  
pp. 849-861 ◽  
Author(s):  
R. J. Wold ◽  
T. L. Woodzick ◽  
N. A. Ostenso
Keyword(s):  
Transition Zone ◽  
Continental Margin ◽  
Gravity Data ◽  
Beaufort Sea ◽  
Continental Margins ◽  
Banks Island ◽  
Basement Rocks ◽  
Area North ◽  
Free Air Anomaly ◽  
Gravity Map

An airlifted gravity survey was conducted in 1968 in the Beaufort Sea between Barter Island and Banks Island, south into the Mackenzie River Delta area and northward to about 74° latitude. The 1968 gravity data were combined with data from previous airlifted surveys and ice island T‐3. The major feature of the free‐air anomaly gravity map of this area is a more or less continuous 100 mgal high paralleling the coast from Barrow, Alaska, to the edge of the survey area north of Banks Island. The gravity high is explained by a thinning of the crust and a ridge in the basement rocks at about the 200 m isobath. This linear anomaly is broken by saddles off the Colville, Mackenzie, and Bernard Rivers, which are interpreted to reflect sedimentary fans built by the discharge of these rivers. Two‐dimensional crustal models constructed from gravity profiles indicate a narrow transition zone from ocean to continental crustal thickness, 55 km to 100 km shoreward of the 2000 m isobath. In a review of continental margin structure, Worzel (1968) found the transition zone to be centered under the 2000 m isobath. The departure from “normal” in the Beaufort Sea area may be explained by a greater accumulation of sediments seaward of the “structural” continental margins. This accumulation implies a faster rate of sedimentation and/or a greater age for the Beaufort Sea continental margins than for those analyzed by Worzel.

scholarly journals Gravity measurements over the Beaufort Sea, Banks Island and Mackenzie Delta

10.4095/8396 ◽  
1973 ◽  
Author(s):  
L W Sobczak ◽  
L E Stephens ◽  
P J Winter ◽  
D B Hearty
Keyword(s):  
Beaufort Sea ◽  
Mackenzie Delta ◽  
Banks Island ◽  
Gravity Measurements

Evaluation of net shortwave radiation over China with a regional climate model

2020 ◽  
Vol 80 (2) ◽  
pp. 147-163
Author(s):  
X Liu ◽  
Y Kang ◽  
Q Liu ◽  
Z Guo ◽  
Y Chen ◽  
...  
Keyword(s):  
Regional Climate Model ◽  
Climate Model ◽  
Regional Climate ◽  
Radiant Energy ◽  
Energy System ◽  
Radiation Budget ◽  
Shortwave Radiation ◽  
Monsoon Region ◽  
Clear Sky ◽  
Sky Conditions

The regional climate model RegCM version 4.6, developed by the European Centre for Medium-Range Weather Forecasts Reanalysis, was used to simulate the radiation budget over China. Clouds and the Earth’s Radiant Energy System (CERES) satellite data were utilized to evaluate the simulation results based on 4 radiative components: net shortwave (NSW) radiation at the surface of the earth and top of the atmosphere (TOA) under all-sky and clear-sky conditions. The performance of the model for low-value areas of NSW was superior to that for high-value areas. NSW at the surface and TOA under all-sky conditions was significantly underestimated; the spatial distribution of the bias was negative in the north and positive in the south, bounded by 25°N for the annual and seasonal averaged difference maps. Compared with the all-sky condition, the simulation effect under clear-sky conditions was significantly better, which indicates that the cloud fraction is the key factor affecting the accuracy of the simulation. In particular, the bias of the TOA NSW under the clear-sky condition was <±10 W m-2 in the eastern areas. The performance of the model was better over the eastern monsoon region in winter and autumn for surface NSW under clear-sky conditions, which may be related to different levels of air pollution during each season. Among the 3 areas, the regional average biases overall were largest (negative) over the Qinghai-Tibet alpine region and smallest over the eastern monsoon region.

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