Occurrence and effects of open water in McMurdo Sound, Antarctica, during winter and early spring

Polar Record ◽  
1967 ◽  
Vol 13 (87) ◽  
pp. 775-778 ◽  
Author(s):  
B. Stonehouse
Keyword(s):  
Late Summer ◽  
Open Water ◽  
Early Spring ◽  
Easy Access ◽  
High Latitudes ◽  
Mcmurdo Sound ◽  
Pack Ice ◽  
Fast Ice

McMurdo Sound is well known as an area comparatively free from fast ice during the middle and late summer. Although closed to its discoverer in February 1841 by contrary winds, pack ice and new ice (Ross, 1847), the sound provided easy access to high latitudes in January and February on at least ten occasions between 1902 and 1916. Since 1955, icebreakers have assisted shipping movements in November and December, and possibly helped in dispersing the winter fast ice by cutting wide channels from Cape Bird southward. However, northerly swells and south-easterly gales are sufficient in most years to disperse fast ice from the southern end of the sound by mid or late February (Heine, 1963).

Observations on the Quaternary geology around Nioghalvfjerdsfjorden, eastern North Greenland

1999 ◽  
pp. 56-60
Author(s):  
Ole Bennike ◽  
Anker Weidick
Keyword(s):  
Late Summer ◽  
Open Water ◽  
Quaternary Geology ◽  
Mean Annual Precipitation ◽  
Outlet Glacier ◽  
Ice Caps ◽  
North East ◽  
Pack Ice ◽  
Lake Deposits ◽  
North Greenland

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Bennike, O., & Weidick, A. (1999). Observations on the Quaternary geology around Nioghalvfjerdsfjorden, eastern North Greenland. Geology of Greenland Survey Bulletin, 183, 56-60. https://doi.org/10.34194/ggub.v183.5205 _______________ In North and North-East Greenland, several of the outlet glaciers from the Inland Ice have long, floating tongues (Higgins 1991). Nioghalvfjerdsfjorden (Fig. 1) is today occupied by a floating outlet glacier that is about 60 km long, and the fjord is surrounded by dissected plateaux with broad valleys (Thomsen et al. 1997). The offshore shelf to the east of Nioghalvfjerdsfjorden is unusually broad, up to 300 km wide (Cherkis & Vogt 1994), and recently small low islands were discovered on the western part of this shelf (G. Budeus and T.I.H. Andersson, personal communications 1998). Quaternary deposits are widespread around Nioghalvfjerdsfjorden and include glacial, glaciofluvial, marine, deltaic and ice lake deposits. Ice margin features such as kame deposits and moraines are also common (Davies 1972). The glaciation limit increases from 200 m a.s.l. over the eastern coastal islands to 1000 m in the inland areas; local ice caps and valley glaciers are common in the region, although the mean annual precipitation is only about 200 mm per year. Most of the sea in the area is covered by permanent sea ice, with pack ice further east, but open water is present in late summer in some fjords north of Nioghalvfjerdsfjorden, and in the Nordøstvandet polynia.

scholarly journals Physical and Structural Characteristics of Antarctic Sea Ice

1982 ◽  
Vol 3 ◽  
pp. 113-117 ◽  
Author(s):  
A.J. Gow ◽  
S.F. Ackley ◽  
W.F. Weeks ◽  
J.W. Govoni
Keyword(s):  
Sea Ice ◽  
Structural Characteristics ◽  
Weddell Sea ◽  
The Arctic ◽  
Mcmurdo Sound ◽  
Frazil Ice ◽  
Antarctic Sea Ice ◽  
Pack Ice ◽  
Fast Ice ◽  
Ice Production

Observations during February and March 1980 of structures in 66 separate floes in Weddell Sea pack ice show widespread occurrence of frazil ice in amounts not previously reported in sea ice of comparable age and thickness in the Arctic. It is estimated that as much as 50% of the total ice production in the Weddell Sea is generated as frazil. Average floe salinities also appear higher than those of their Arctic counterparts. Comparative studies of fast ice at 28 locations in McMurdo Sound show this ice to be composed almost entirely of congelation ice that exhibits crystalline textures and orientations that are similar to those observed in Arctic fast ice. However, average fast-ice salinities in McMurdo Sound are higher than those reported for Arctic fast ice of comparable age and thickness.

Over-winter movements and diving behavior of female Weddell seals (Leptonychotes weddellii) in the southwestern Ross Sea, Antarctica

1994 ◽  
Vol 72 (10) ◽  
pp. 1700-1710 ◽  
Author(s):  
J. Ward Testa
Keyword(s):  
Ross Sea ◽  
Diving Behavior ◽  
Winter Period ◽  
Pleuragramma Antarcticum ◽  
Long Distance ◽  
Leptonychotes Weddellii ◽  
Mcmurdo Sound ◽  
Weddell Seals ◽  
Pack Ice ◽  
Fast Ice

The movements and diving behavior of 18 adult female Weddell seals (Leptonychotes weddellii) were determined by satellite telemetry during the over-winter period in 1990 and 1991. Nine seals provided diving and movement data for 8 – 9 months. Seals that normally bred in the eastern part of McMurdo Sound spent most of the winter in the middle and northern parts of McMurdo Sound before the annual shore-fast ice had formed in those areas, or in the pack ice 0–50 km north of the sound and Ross Island. This is a greater use of pack ice, as opposed to shore-fast ice, in winter than was previously believed. Some long-distance movements (one over 1500 km in total) to the middle and northwestern parts of the Ross Sea also occurred. Although highly variable within and between individuals, dives indicative of foraging were primarily to mid-water regions (100 – 350 m) in both years, and were similar to those that have been observed in spring and summer, when Pleuragramma antarcticum is the primary prey of Weddell seals in McMurdo Sound.

scholarly journals Organic matter pathways to zooplankton and benthos under pack ice in late winter and open water in late summer in the north-central Bering Sea

2005 ◽  
Vol 291 ◽  
pp. 135-150 ◽  
Author(s):  
JR Lovvorn ◽  
LW Cooper ◽  
ML Brooks ◽  
CC De Ruyck ◽  
JK Bump ◽  
...  
Keyword(s):  
Organic Matter ◽  
Bering Sea ◽  
Late Summer ◽  
Open Water ◽  
Late Winter ◽  
North Central ◽  
The North ◽  
Pack Ice

Development of Hull Forms for a 190,000 DWT Icebreaking Ore Carrier

2011 ◽  
Author(s):  
Kyung Duk Park ◽  
Yong Kwan Chung ◽  
Young Sik Jang ◽  
Hyun Soo Kim ◽  
David Molyneux
Keyword(s):  
Open Water ◽  
Bulk Carrier ◽  
Hull Form ◽  
Model Experiments ◽  
Pack Ice ◽  
Ice Conditions ◽  
Level Ice ◽  
Fast Ice ◽  
Improved Performance ◽  
Hull Forms

This paper describes the development of three candidate hull forms for 190,000 DWT ore carrier for operation in ice covered water. It builds on Hyundai Heavy Industries expertise in ore carrier design, and discusses some of the changes required for operation in heavy ice conditions. The overall concept was to have a target speed of 6 knots in land fast ice 1.7m thick and 15 knots in open water. Three candidate bow shapes were designed and analyzed, based on a common stern arrangement. The development of the hull form included three methods of predicting the performance of the ships in ice. Empirical analysis was carried out for all three hulls, based on experience gained from model experiments on bulk carrier hull forms in ice. Numerical analysis was carried out on all three bow shapes using a computer program (based on the discrete element method) to simulate the interaction between the ship and the ice. Physical model experiments were carried out for resistance and propulsion in level ice, pack ice and ridges on the selected design. As a result of the model experiments, the selected bow shape was modified to reduce its resistance in ice. The improved performance of the modified hull was confirmed with additional numerical simulations.

Local climatology of fast ice in McMurdo Sound, Antarctica

2018 ◽  
Vol 30 (2) ◽  
pp. 125-142 ◽  
Author(s):  
Stacy Kim ◽  
Ben Saenz ◽  
Jeff Scanniello ◽  
Kendra Daly ◽  
David Ainley
Keyword(s):  
Sea Ice ◽  
Ross Sea ◽  
Wind Waves ◽  
Marine Ecosystem ◽  
Sea Ice Concentration ◽  
Ice Dynamics ◽  
Mcmurdo Sound ◽  
High Resolution Imagery ◽  
Pack Ice ◽  
Fast Ice

AbstractFast ice plays important physical and ecological roles: as a barrier to wind, waves and radiation, as both barrier and safe resting place for air-breathing animals, and as substrate for microbial communities. While sea ice has been monitored for decades using satellite imagery, high-resolution imagery sufficient to distinguish fast ice from mobile pack ice extends only back to c. 2000. Fast ice trends may differ from previously identified changes in regional sea ice distributions. To investigate effects of climate and human activities on fast ice dynamics in McMurdo Sound, Ross Sea, the sea and fast ice seasonal events (1978–2015), ice thicknesses and temperatures (1986–2014), wind velocities (1973–2015) and dates that an icebreaker annually opens a channel to McMurdo Station (1956–2015) are reported. A significant relationship exists between sea ice concentration and fast ice extent in the Sound. While fast/sea ice retreat dates have not changed, fast/sea ice reaches a minimum later and begins to advance earlier, in partial agreement with changes in Ross Sea regional pack ice dynamics. Fast ice minimum extent within McMurdo Sound is significantly correlated with icebreaker arrival date as well as wind velocity. The potential impacts of changes in fast ice climatology on the local marine ecosystem are discussed.

Sea ice conditions during an early spring voyage in the eastern Weddell Sea, Antarctica

Polar Record ◽  
1988 ◽  
Vol 24 (148) ◽  
pp. 49-54 ◽  
Author(s):  
H. Eicken ◽  
T. C. Grenfell ◽  
B. Stonehouse
Keyword(s):  
Open Water ◽  
Early Spring ◽  
Early Summer ◽  
Weddell Sea ◽  
Late Winter ◽  
Main Body ◽  
Pack Ice ◽  
Large Populations ◽  
Differential Expansion ◽  
Ice Pack

AbstractDuring a late winter and early spring oceanographic voyage south into the Weddell Sea the icebreaker RV Polarstern first encountered patches and bands of loose floes in 58°S; these increased over the next 150 km to form closed ice pack which extended 1000 km to the coast. Along the coast the ship encountered almost continuous shore leads and polynyas that formed repeatedly despite persistently low air and sea temperatures. These areas of open water, which are generally visible in USA NOAA and USSR METEOR satellite photographs, form under the action of strong offshore winds that carry the main body of pack ice west and southwest. Grease ice, pancake ice and nilas spreading over the open water are rafted and ridged by windgenerated stresses to double thickness or more; these kinds of ice were continually driven westward, accumulating in a distinctive zone along the eastern edge of the pack ice. Polynyas and leads narrow and disappear temporarily only when winds with northerly or westerly components bring the pack ice toward the land, and reform as soon as offshore winds predominate. Open water, often more than 15 km wide, was present close to the ship throught the spring voyage, facilitating oceanographic work as far south as 77°S. Polarstern's full icebreaking capacity was needed only occasionally when winds temporarily pressed the pack ice against the coast. The presence throughout early spring of both fast and pack ice, separated by a zone of thin ice or open water, is essential to large populations of Weddell seals, emperor penguins and whales in the area. The transect from the continent included ice pack that was undergoing early summer decay, characterized by differential expansion and melting which brought about a gradual decrease in concentration toward the ice edge.

Sealing and sealing methods in the Bay of Bothnia, 1551–70

Polar Record ◽  
1991 ◽  
Vol 27 (163) ◽  
pp. 339-344 ◽  
Author(s):  
Roger Kvist
Keyword(s):  
Prey Species ◽  
Open Water ◽  
16Th Century ◽  
Species Numbers ◽  
Ringed Seals ◽  
Pack Ice ◽  
Tax Returns ◽  
Fast Ice ◽  
Ice Edge

AbstractSeals were hunted in the Bay of Bothnia during the 16th century in four areas — inshore open water, fast ice, ice edge, and pack ice — with methods appropriate for each area. Inshore open water sealing involved netting and some seining, exclusively for ringed seals. On fast ice the techniques used were stalking, den-hunting, and breathing hole-hunting, again for ringed seals. Grey and ringed seals were hunted on the ice edge. Provincial tax returns have provided information on methods used by sealers from different parishes in the Bay of Bothnia area. Catching techniques, tools, prey species, numbers of crews, hunting seasons, catch figures and annual yields are discussed.

scholarly journals Physical and Structural Characteristics of Antarctic Sea Ice

1982 ◽  
Vol 3 ◽  
pp. 113-117 ◽  
Author(s):  
A.J. Gow ◽  
S.F. Ackley ◽  
W.F. Weeks ◽  
J.W. Govoni
Keyword(s):  
Sea Ice ◽  
Structural Characteristics ◽  
Weddell Sea ◽  
The Arctic ◽  
Mcmurdo Sound ◽  
Frazil Ice ◽  
Antarctic Sea Ice ◽  
Pack Ice ◽  
Fast Ice ◽  
Ice Production

Observations during February and March 1980 of structures in 66 separate floes in Weddell Sea pack ice show widespread occurrence of frazil ice in amounts not previously reported in sea ice of comparable age and thickness in the Arctic. It is estimated that as much as 50% of the total ice production in the Weddell Sea is generated as frazil. Average floe salinities also appear higher than those of their Arctic counterparts. Comparative studies of fast ice at 28 locations in McMurdo Sound show this ice to be composed almost entirely of congelation ice that exhibits crystalline textures and orientations that are similar to those observed in Arctic fast ice. However, average fast-ice salinities in McMurdo Sound are higher than those reported for Arctic fast ice of comparable age and thickness.

scholarly journals The distribution and formative processes of latent-heat polynyas in East Antarctica

1998 ◽  
Vol 27 ◽  
pp. 420-426 ◽  
Author(s):  
R. A. Massom ◽  
P.T. Harris ◽  
Kelvin J. Michael ◽  
M.J. Potter
Keyword(s):  
Open Water ◽  
East Antarctica ◽  
Emperor Penguin ◽  
Spatial And Temporal Variability ◽  
Areal Extent ◽  
Study Region ◽  
Pack Ice ◽  
Ice Concentration ◽  
Fast Ice ◽  
Microwave Imager

A study of polynya characteristics in East Antarctica was undertaken using ice concentrations derived from special sensor microwave/imager data for the period July 1987-August 1994. The areas of polynyas were defined as having an ice concentration ≤75%. The analysis revealed a total of 28 coastal polynyas within the study region. The spatial and temporal variability in areal extent was quantified. The timing of mean maximum areal extent varied from June to October. The bathymetry and wind regime at each polynya site was examined to gauge the relative importance of these parameters in polynya formation and maintenance. In 20 locations, shallow banks and shoals form grounding zones for icebergs and anchoring sites for fast ice, which form barriers to the predominantly westward drift of the pack ice; elsewhere north-south coastal protrusions or alignments form similar barriers. The subsequent removal of newly formed sea ice from the lee of such barriers by katabatic and synoptic winds maintains areas of reduced ice concentration and open water. Very few coastal polynyas are attributed solely to katabatic outflow. The combined influence of bathymetry, topography and winds is responsible for the characteristics of the majority of polynyas. Many were considered to be marginal, characterised by occasional periods when the ice concentration falls below 75%. An analysis of annual winter totals of areas with ice concentrations < 75% shows no trends in total polynya areal extent over the period 1987-94. Known locations of emperor penguin (Aptenodytes forsteri) rookeries were also found to be associated with the locations of coastal polynyas.

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