Interaction of Vessel with Channel under Navigation among Small Ice Floes

2015 ◽  
Author(s):  
Vadim K. Goncharov ◽  
Ekaterina S. Zueva ◽  
Natalia Yu. Klementieva
Keyword(s):  
Ice Cover ◽  
Problem Definition ◽  
Arctic Seas ◽  
Cross Sectional ◽  
Side Force ◽  
Pack Ice ◽  
Cross Sectional Dimension ◽  
Ice Conditions ◽  
Fast Ice ◽  
Ice Floes

For maintenance of navigation during wintertime in Arctic seas, icebreakers create the wide channels in the fast ice cover or pack ice cover at water areas near to ports with intensive vessel traffic. Within such wide channels cargo ships and tankers can move in both directions independently without icebreaker pilotage among small ice floes. Because the cross-sectional dimension of the channel is restricted, the ships are forced to displace from the center and move on a close distance between their board and border of channel. The space between ship hull and borders is filled by small ice floes, and its concentration near the starboard and portside differs. The ice resistance on each board also differs. Therefore, side force and yawing moment arise that are able to cause the collision with the channel border. This paper contains the detailed problem definition and the main points of the mathematical model of vessel interaction with the channel border. As an example of model application possibilities, the simulation of loads on the hull of the vessel was performed. Outcomes of the investigation are dependent upon the side force and yawing moment on the distance from the channel border and ice conditions.

New records of mummified crabeater seals on islands bordering Admiralty Sound, Weddell Sea

2019 ◽  
Vol 31 (3) ◽  
pp. 109-115
Author(s):  
Javier Negrete ◽  
Leopoldo H. Soibelzon ◽  
Esteban Soibelzon ◽  
Jorge Lusky
Keyword(s):  
Open Water ◽  
Weddell Sea ◽  
Pack Ice ◽  
Breeding Grounds ◽  
Ice Conditions ◽  
Crabeater Seals ◽  
Ice Floes ◽  
Early Breakup ◽  
Natural Trap ◽  
Seymour Island

AbstractNinety-six mummified crabeater seals discovered at Seymour Island (Isla Marambio) are reported. Each specimen was georeferenced, photographed and assigned to five different taphonomic states. Previous work stated that seals at Seymour Island get stranded inland around the breeding season. However, it is not clear if the species breeds in this area. The abundance of crabeater seals and the ice condition along Admiralty Sound (Estrecho Bouchard) were obtained by aerial surveys during spring (2015–17). It appears that the species uses the strait as a passage to breeding grounds. Under heavy ice conditions, the seals become stranded in the middle section of this strait and wander inland through a valley that represents the mouth of an ephemeral stream that ends at the pack ice level. This situation was observed in 2014 and 2015 when recently dead seals were found, evidencing that this natural trap is still active. Nonetheless, in 2016 and 2017, during an early breakup of Admiralty Sound, the seals that remained in the area were more numerous than in 2015 but they did not get stranded inland. This early breakup may encourage the seals to breed there in the presence of open water areas with ice floes.

Discrete Element Modelling of Pack Ice Interaction With Floating Structures

2015 ◽  
Author(s):  
Jie Dai ◽  
Heather Peng
Keyword(s):  
Discrete Element ◽  
Wave Force ◽  
Interaction Force ◽  
Discrete Element Modelling ◽  
Empirical Formulas ◽  
Pack Ice ◽  
Broken Ice ◽  
Ice Conditions ◽  
Ice Field ◽  
Ice Floes

This paper presents a two-dimensional numerical model for ship-ice interaction simulatiion using the discrete element method (DEM). The simulation was conducted for a broken ice field with hundreds of circular ice floes and various combinations of ice conditions. A viscous-elastic ice rheology was adopted to model the dynamic behavior of each individual ice floe. Both ship-ice and ice-ice contacts were considered in the interaction force. Environment forces, including wind force and wave force, were calculated by empirical formulas. An algorithm was developed to log each contact and solve motions of individual ice floe and the ship. The resistance of ship advancing in ice was predicted and compared with model test results.

Methods of parameters estimate of ice formations

2019 ◽  
Vol 65 (1) ◽  
pp. 77-91
Author(s):  
A. K. Naumov ◽  
E. A. Skutina
Keyword(s):  
Dynamic Characteristics ◽  
Ice Cover ◽  
Aerial Survey ◽  
Water Area ◽  
Morphometric Parameters ◽  
The Arctic ◽  
Arctic Seas ◽  
Protection Measures ◽  
Ice Floes ◽  
Ice Radar

The ice cover of the Arctic Seas is an important component of the natural conditions. It is impossible the construction and safe exploitation of the hydrotechnical structures and lines of communications on the shelf, reasonable planning and conducting of cargo and transport operations, organization of environmental protection measures without taking into account an ice cover.The information on morphometric and dynamic characteristics of ice formations, physical and mechanical ice properties, presence of icebergs and its bergy bits with various mortphometric and dynamic characteristics in the water area are necessary for an organization of successful activity on the shelf (design of hydrotechnical structures, planning of the work etc).The present article is concerned with the issues of estimation of ice formations morphometric parameters. The different remote observations methods on ice floes and icebergs are considered in the article: aerial survey, radar survey, observations using ice radar and geodetic instruments, visual observations, sonar survey of ice cover.The goal of the work is the description of peculiarities of various remote methods of observations. For each of the considered methods, the conditions of its application and peculiarities of data obtainment are considered; the list of morphometric parameters, that can be estimated, using results of corresponding observations is indicated.The mentioned algorithms and formulas are actively used during ice surveying works at the present time. The knowledge of various methods peculiarities allows to plan the composition of research works depending on their goals and tasks, determine the terms of their performance.The main merits and demerits of the considered methods of data obtainment and estimations of ice formations morphometrical parameters are phrased in the conclusion.

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.

scholarly journals Sea ice and the stability of north and northeast Greenland floating glaciers

2001 ◽  
Vol 33 ◽  
pp. 474-480 ◽  
Author(s):  
Niels Reeh ◽  
Henrik Højmark Thomsen ◽  
Anthony K. Higgins ◽  
Anker Weidick
Keyword(s):  
Sea Ice ◽  
Ice Cover ◽  
Aerial Photographs ◽  
The Arctic ◽  
The North ◽  
Glacier Ice ◽  
Ice Conditions ◽  
Fast Ice ◽  
Break Up ◽  
The Stability

AbstractThe interaction between sea ice and glaciers has been studied for the floating tongue of Nioghalvfjerdsfjorden glacier, northeast Greenland (79°30’N, 22° W). Information from glacial geological studies, expedition reports, aerial photographs and satellite imagery is used to document the glacier front position and fast-ice conditions on millennial to decadal time-scales. The studies indicate that the stability of the floating glacier margin is dependent on the presence of a protecting fast-ice cover in front of the glacier. In periods with a permanent fast-ice cover, no calving occurs, but after fast-ice break-up the glacier responds with a large calving activity, whereby several years of accumulated glacier-ice flux suddenly breaks away. Climate-induced changes of sea-ice conditions in the Arctic Ocean with seasonal break-up of the near-shore fast ice could lead to disintegration of the floating glaciers. The present dominant mass loss by bottom melting would then to a large extent be taken over by grounding-line calving of icebergs. The local influx of fresh water from the north Greenland glaciers to the sea would be reduced and the local iceberg production would increase.

scholarly journals Coastal fast ice in the Shokalski Strait

2016 ◽  
Vol 56 (4) ◽  
pp. 525-532 ◽  
Author(s):  
V. A. Borodkin ◽  
A. P. Makshtas ◽  
P. V. Bogorodsky
Keyword(s):  
Sea Ice ◽  
Ice Cover ◽  
Early Spring ◽  
The Arctic ◽  
Similar Process ◽  
Research Station ◽  
Arctic Seas ◽  
Sea Ice Thickness ◽  
Ice Growth ◽  
Fast Ice

Field investigations of coastal fast ice near the research station Ice Base on the «Cape Baranova», carried out in 2013–2014, made possible to reveal a number of characteristics of the sea ice cover formation. It has been shown that during winter and early spring the sea ice thickness, being formed due to intensive snow drift and caused by that flooding of the ice cover just near the coast of the Bolshevik Island, substantially grows at its upper boundary, that is typical for the Antarctic seas. At the same time, similar process of the ice growth at a relatively short distance from the coast shows all features characteristic for the ice cover in the Arctic seas, and that is well reproduced by the conceptual numerical sea ice model. Thus, the region of the Ice Base «Cape Baranova» represents a natural laboratory for studying the processes of the sea ice formation in both, the Arctic and Antarctic seas under condition of the same atmospheric forcing. Transformation of the fast ice structure during the summer time is described. Results of the investigations has demonstrated that despite the radical changes in the structure thicknesses of the fast ice remained almost unchanged due to the ice growth on the bottom boundary of the ice cover until a destruction of it in August.

A top–down, multidisciplinary study of the structure and function of the pack-ice ecosystem in the eastern Ross Sea, Antarctica

Polar Record ◽  
2003 ◽  
Vol 39 (3) ◽  
pp. 219-230 ◽  
Author(s):  
S.F. Ackley ◽  
J.L. Bengtson ◽  
P. Boveng ◽  
M. Castellini ◽  
K.L. Daly ◽  
...  
Keyword(s):  
Ross Sea ◽  
Structure And Function ◽  
Potential Prey ◽  
Apex Predators ◽  
Pack Ice ◽  
Coastal Shelf ◽  
Fast Ice ◽  
Ice Floes ◽  
Shelf Region ◽  
And Function

We used a top–down, multidisciplinary approach to examine the physical and biological environment of the pack ice of the eastern Ross Sea (approximately 125–170°W) during the austral summer of 1999/2000 from RVIB Nathaniel B. Palmer and its ship-based helicopters. The approach focused on pack-ice seals while incorporating studies of biotic and abiotic factors that may influence the distribution and abundances of these apex predators in the Ross Sea to yield a holistic understanding of the structure and function of this complex, large marine ecosystem. This research represented the US component of the international Antarctic Pack Ice Seal (APIS) program, which was designed to document the circumpolar distribution and abundance of Antarctic pack-ice seals. The eastern Ross Sea is one of the two major areas in the Southern Ocean where substantial pack ice exists throughout summer. We found that vast multi-year ice floes (>20 km diameter) and smaller floes north of the shore-fast ice front provide a unique habitat for seals and penguins (apex predators) to forage and haul out while molting in late summer. Farther north, more Ross seals were observed than in any previous surveys in the circumpolar pack ice, perhaps because they are attracted to the area in summer to molt on large stable first-year ice floes. Extensive fast ice along the coastline and drifting pack ice in the shelf–slope boundary zone provided haul-out areas for seals and penguins with access to feeding in the coastal shelf region. Distributions of potential prey for seals and penguins varied over the study area, as determined by nets, acoustics, and diving surveys. Antarctic krill (Euphausia superba) were found throughout the survey region, overlapping the distributions of two smaller species, Thysanoëssa macrura (primarily off-shelf) and E. crystallorophias (primarily found on-shelf). In some locations, E. superba occurred at high densities underneath ice floes, where they foraged on the sea-ice microbial community. Two general fish communities, oceanic and shelf, were distinguished. Off-shelf fishes were members of the classic oceanic midwater fish fauna, whereas on-shelf fishes were Antarctic endemics. The abundance of pelagic fishes was relatively low throughout the study area compared with other Southern Ocean ecosystems. In contrast, benthic fish biomass and diversity on-shelf were high (41 species, 6 families). Hydroacoustic analyses indicated that densities of potential prey were highest in the coastal shelf region where large aggregations of euphausiids (primarily E. crystallorophias) and individual juvenile Antarctic silverfish (Pleuragramma antarcticum) occurred.

Impact of the Mertz Glacier Tongue calving on the emergence of polynyas in the d'Urville Trough, East Antarctica

2020 ◽  
Author(s):  
Lucile Ricard ◽  
Marie-Noelle Houssais ◽  
Christophe Herbaut ◽  
Alexander Fraser ◽  
Rob Massom ◽  
...  
Keyword(s):  
Sea Ice ◽  
Microwave Remote Sensing ◽  
Sea Ice Concentration ◽  
Glacier Tongue ◽  
Pack Ice ◽  
Ice Concentration ◽  
Ice Conditions ◽  
Fast Ice ◽  
Ice Production ◽  
The Impact

<p> </p><p><br>Passive microwave remote sensing observations and atmospheric data are used to characterize the impact of the Mertz Glacier Tongue (MGT) calving in February 2010 on the sea ice conditions in the D’Urville Trough, East Antarctic shelf (139°E-141°E). The main objective is to determine if conditions for dense shelf water production in this area were possibly influenced by the calving. In particular, we look for the existence of winter polynyas capable of sustaining significant sea ice production, a prerequisite for the formation of dense, saline waters. We show that polynyas in the D'Urville area are part of a complex icescape made of fast ice and drifting pack ice. The seasonal evolution of this icescape has been profoundly modified with the calving of the MGT and opening of new polynyas. Pre-calving and post-calving sea ice concentrations are analyzed to identify major patterns of variability. Examination of the fast ice distribution and atmospheric forcing helps to develop a scenario for the formation of low sea ice concentration regions and their relation to the sea ice fluxes, supporting the conclusion that the role of the Adelie Bank as a barrier to the drift ice may have strengthened after the calving.</p>

Causes of a Vessel Navigation Disruption Event in Pack Ice on the Umiak I During March 29-31, 2016

2017 ◽  
Author(s):  
Ian D. Turnbull ◽  
Rocky S. Taylor ◽  
Pascale Bourbonnais ◽  
Marie-Andrée Giguère
Keyword(s):  
Shear Zone ◽  
Predictive Models ◽  
Extreme Conditions ◽  
Significant Progress ◽  
Operational Costs ◽  
Pack Ice ◽  
Ice Conditions ◽  
Fast Ice ◽  
Ice Pressure ◽  
Disruption Event

Pack ice pressure events and heavily deformed shear zone and land-fast ice conditions can cause serious disruption to vessel navigation through ice-infested waters, resulting in operational delays and increased costs due to downtime. Understanding the causes behind ice-related vessel navigation disruption events is critical to efforts to build predictive models for such events. These models will help offshore operators prepare for and avoid such events, thus decreasing downtime, lowering operational costs, and improving safety. This paper examines a three-day period during which operations of the Umiak I, an ice-strengthened vessel owned and operated by Fednav Limited, were repeatedly disrupted by extreme ice conditions in the shear zone offshore Voisey’s Bay, Labrador. During March 29–31, 2016, the Umiak I was unable to make significant progress through the 9–10/10ths concentration ice in the shear zone and land-fast ice east of Voisey’s Bay, and engaged in prolonged backing and ramming maneuvers in order to break through the pack. This study examines the regional metocean factors during the two months prior which led to the extreme conditions in the shear zone and caused the vessel navigation disruption event.

scholarly journals Sea ice cover in Isfjorden and Hornsund 2000–2014 by using remote sensing

2015 ◽  
Vol 9 (4) ◽  
pp. 4043-4066
Author(s):  
S. Muckenhuber ◽  
F. Nilsen ◽  
A. Korosov ◽  
S. Sandven
Keyword(s):  
Sea Ice ◽  
Open Water ◽  
Ice Cover ◽  
Ice Coverage ◽  
Time Period ◽  
Ice Drift ◽  
Before And After ◽  
Ice Conditions ◽  
Fast Ice ◽  
The Mean

Abstract. A satellite database including 16 555 satellite images and ice charts displaying the area of Isfjorden, Hornsund and the Svalbard region has been established with focus on the time period 2000–2014. 3319 manual interpretations of sea ice conditions have been conducted, resulting in two time series dividing the area of Isfjorden and Hornsund into "Fast ice", "Drift ice" and open "Water". The maximum fast ice coverage of Isfjorden is > 40 % in the periods 2000–2005 and 2009–2011 and stays < 30 % in 2006–2008 and 2012–2014. Fast ice cover in Hornsund reaches > 40 % in all considered years, except for 2012 and 2014, where the maximum stays < 20 %. The mean seasonal cycles of fast ice in Isfjorden and Hornsund show monthly averaged values of less than 1 % between July and November and maxima in March (Isfjorden, 35.7 %) and April (Hornsund, 42.1 %) respectively. A significant reduction of the monthly averaged fast ice coverage is found when comparing the time periods 2000–2005 and 2006–2014. The seasonal maximum decreases from 57.5 to 23.2 % in Isfjorden and from 52.6 to 35.2 % in Hornsund. A new concept, called "days of fast ice coverage" (DFI), is introduced for quantification of the interannual variation of fast ice cover, allowing for comparison between different fjords and winter seasons. Considering the time period from 1 March until end of sea ice season, the mean DFI values for 2000–2014 are 33.1 ± 18.2 DFI (Isfjorden) and 42.9 ± 18.2 DFI (Hornsund). A distinct shift to lower DFI values is observed in 2006. Calculating a mean before and after 2006 yields a decrease from 50 to 22 DFI for Isfjorden and from 56 to 34 DFI for Hornsund.

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