The Study on the Ice Sea Trial in Chukchi Sea Using Korean Icebreaker “Araon”

2011 ◽  
Author(s):  
Hyun Soo Kim ◽  
Chun-Ju Lee ◽  
Kyungsik Choi
Keyword(s):  
Chukchi Sea ◽  
Video Recording ◽  
The Arctic ◽  
Research Vessel ◽  
Ice Thickness ◽  
Sea Trial ◽  
Level Ice ◽  
Ice Strength ◽  
Ice Floes ◽  
Ship Speed

The ice sea trial measurement in Chukchi Sea using research vessel Araon was performed on July 2010. It was the first voyage to the Arctic Sea. The latitude of the route was between 73 degree north to 80 degree north. Araon is the first Korean Ice breaking research vessel. The principle dimension is 110m length, 19m beam and 7.3m draft. Araon was designed to break 1.0m level ice of 630 kPa flexible ice strength. Four attempts to know the performance of the ship in Arctic region were carried out and the results were summarized in this paper. The basic datum for the sea trial such as ship speed, power of engine, wind speed, location of the ship, air temperature, drafts, heading of the ship etc., were measured during the trail in every second by the video recording. Simultaneously the ice information such as ice thickness, compressive strength, temperature of ice, snow depth, free board of ice floe were measured in each field by the coring tool, auger and compression test equipment. The ice sea trial was performed in large ice floes rather than level ice because the sea ice condition on July and August in Chukchi Sea has no uniform level ice and starts to melt. The size of four ice floes is about 100m to 300m length and 100m to 200m wide beam. It was some second year ice and most of first year ice floes. The mean flexible strength of ice was less than 250 kPa. The analysis result of the ice sea trial shows the relation between the ice thickness, ice strength, ship speed and power of engine. Araon is possible to operate at 1.5 knots in 2.5m ice thickness with 5 MW engine power when the strength of ice floe is 250 kPa. The speed reaches 3.1 knots at same ice condition if the power is increasing up to 6.6 MW. She has good performance compare to the design target (3 knots in 1.0m level ice and 630 kPa of flexible strength) but it’s come from the different ice types and low flexible ice strength. The more detail analysis result was discussed in this paper.

Hydrodynamic Interaction of Ice Sheet and a Floating Platform

2016 ◽  
Author(s):  
Aziz Ahmed ◽  
Mohammed Abdul Hannan ◽  
Xudong Qian ◽  
Bai Wei
Keyword(s):  
Model Test ◽  
The Arctic ◽  
Wave Direction ◽  
Hydrodynamic Behavior ◽  
Incoming Wave ◽  
Hydrodynamic Analysis ◽  
Hydrodynamic Response ◽  
Level Ice ◽  
Ice Floes ◽  
Multi Body

Arctic is the one of the final frontiers in the field of oil and gas exploration. It is also a potential source of the vast amount of renewable energy using wind turbines and wave energy converters. Floating platforms hold certain advantages over fixed platforms for such harsh environment, as they allow disconnection and reconnection in the event of large icebergs or vast multi-year ice floes. They are also commercially attractive as they allow redeployment in other regions during the Arctic off-peak periods. However, such platforms will still need to encounter and withstand first-year level ice of varying sizes and from different directions. Such large ice floes will interfere with the hydrodynamic response of the floater. The hydrodynamic analysis of an isolated floater without accounting for the effect of the level ice is incomplete and may result in a un-conservative prediction of the floater’s response. The lack of any simple methodology to account for the effect of level ice on the hydrodynamic behavior of the floater is the motivation behind this study. This study aims to identify the most relevant parameters affecting the multi-body hydrodynamic behavior of level ice and a single floater. A standard semi-submersible represents the floater, and a range of geometric variations of the level ice simulates the varying nature of the ice environment encountered by the floaters in the Arctic. This study validates the hydrodynamic analysis procedure against model test on an ice floe and wave interaction. The calibration of the model test provides the damping coefficient required for the frequency domain, multi-body hydrodynamic model. This investigation varies the ice orientation and distance from the floater for a detailed parametric study employing the calibrated model. Current research finds that the presence of a comparably sized level ice floe near the floater significantly influences the hydrodynamic Response Amplitude Operator (RAO) of the floater. It can diminish the RAOs in some degree of freedom while enhancing the RAOs in other degree of freedoms. This study identifies the wave direction, ice floe distance, ice floe orientation as the most important parameters. Sway and pitch motion of the floater experienced the most enhancements due to the presence of level ice floe along the incoming wave direction. Additionally, this study proposes some initial upper bound values to account for the effect of level ice floes on the RAOs generated from a single body hydrodynamic analysis.

scholarly journals A Multithickness Sea Ice Model Accounting for Sliding Friction

2006 ◽  
Vol 36 (9) ◽  
pp. 1719-1738 ◽  
Author(s):  
Alexander V. Wilchinsky ◽  
Daniel L. Feltham ◽  
Paul A. Miller
Keyword(s):  
Sea Ice ◽  
Sliding Friction ◽  
Kinematic Model ◽  
The Arctic ◽  
Ice Thickness ◽  
Sea Ice Thickness ◽  
Model Code ◽  
Ice Strength ◽  
Discrete Element Simulations ◽  
Ice Model

Abstract A multithickness sea ice model explicitly accounting for the ridging and sliding friction contributions to sea ice stress is developed. Both ridging and sliding contributions depend on the deformation type through functions adopted from the Ukita and Moritz kinematic model of floe interaction. In contrast to most previous work, the ice strength of a uniform ice sheet of constant ice thickness is taken to be proportional to the ice thickness raised to the 3/2 power, as is revealed in discrete element simulations by Hopkins. The new multithickness sea ice model for sea ice stress has been implemented into the Los Alamos “CICE” sea ice model code and is shown to improve agreement between model predictions and observed spatial distribution of sea ice thickness in the Arctic.

scholarly journals Indirect measurements of the mass balance of summer Arctic sea ice with an electromagnetic induction technique

2001 ◽  
Vol 33 ◽  
pp. 194-200 ◽  
Author(s):  
H. Eicken ◽  
W. B. Tucker ◽  
D. K. Perovich
Keyword(s):  
Mass Balance ◽  
Electromagnetic Induction ◽  
Heat Budget ◽  
Chukchi Sea ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Ice Thickness ◽  
Apparent Conductivity ◽  
Melt Ponds ◽  
Sampling Statistics

AbstractIn the framework of the Surface Heat Budget of the Arctic (SHEBA) study, indirect, non-invasive ice mass-balance measurements were carried out at a drifting station in the northern Chukchi Sea between May and August 1998. Ice thickness was derived from electromagnetic induction (EM) measurements of apparent conductivity along 13 profiles (60−900 m long). As shown through sensitivity studies with a one-dimensional model, the apparent conductivity data from individual points can be inverted to yield estimates of ice thickness and ablation with an accuracy of approximately 0.05 m (for 2 m thick level ice). Ablation rates were 8−18 mm d−1, with total ablation amounting to roughly 0.9−1.2 m. Measurements of thickness and melt rates along different profiles in undeformed multi-year ice corresponded closely, indicating that the sampling statistics are adequate. The roughness of undeformed ice has been found to increase during the summer due to deepening of melt ponds and enhanced bottom melt. Ice under melt ponds was disproportionately thinner, most likely a result of thicker snow cover reducing winter accretion.

scholarly journals A combined approach of remote sensing and airborne electromagnetics to determine the volume of polynya sea ice in the Laptev Sea

2013 ◽  
Vol 7 (1) ◽  
pp. 441-473 ◽  
Author(s):  
L. Rabenstein ◽  
T. Krumpen ◽  
S. Hendricks ◽  
C. Koeberle ◽  
C. Haas ◽  
...  
Keyword(s):  
Sea Ice ◽  
Thickness Distribution ◽  
Growth Conditions ◽  
Ice Age ◽  
The Arctic ◽  
Ice Thickness ◽  
Laptev Sea ◽  
Volume Estimate ◽  
Sea Ice Thickness ◽  
Level Ice

Abstract. A combined interpretation of synthetic aperture radar (SAR) satellite images and helicopter electromagnetic (HEM) sea-ice thickness data has provided an estimate of sea-ice volume formed in Laptev Sea polynyas during the winter of 2007/08. The evolution of the surveyed sea-ice areas, which were formed between late December 2007 and middle April 2008, was tracked using a series of SAR images with a sampling interval of 2–3 days. Approximately 160 km of HEM data recorded in April 2008 provided sea-ice thicknesses along profiles that transected sea-ice varying in age from 1–116 days. For the volume estimates, thickness information along the HEM profiles was extrapolated to zones of the same age. The error of areal mean thickness information was estimated to be between 0.2 m for younger ice and up to 1.55 m for older ice, with the primary error source being the spatially limited HEM coverage. Our results have demonstrated that the modal thicknesses and mean thicknesses of level ice correlated with the sea-ice age, but that varying dynamic and thermodynamic sea-ice growth conditions resulted in a rather heterogeneous sea-ice thickness distribution on scales of tens of kilometers. Taking all uncertainties into account, total sea-ice area and volume produced within the entire surveyed area were 52 650 km2 and 93.6 ± 26.6 km3. The surveyed polynya contributed 2.0 ± 0.5% of the sea-ice produced throughout the Arctic during the 2007/08 winter. The SAR-HEM volume estimate compares well with the 112 km3 ice production calculated with a high resolution ocean sea-ice model. Measured modal and mean-level ice thicknesses correlate with calculated freezing-degree-day thicknesses with a factor of 0.87–0.89, which was too low to justify the assumption of homogeneous thermodynamic growth conditions in the area, or indicates a strong dynamic thickening of level ice by rafting of even thicker ice.

scholarly journals Arctic sea ice drift-strength feedback modelled by NEMO-LIM3.6

2017 ◽  
Author(s):  
David Docquier ◽  
François Massonnet ◽  
Neil F. Tandon ◽  
Olivier Lecomte ◽  
Thierry Fichefet
Keyword(s):  
Sea Ice ◽  
Positive Feedback ◽  
Seasonal Cycle ◽  
The Arctic ◽  
Ice Thickness ◽  
Sea Ice Thickness ◽  
Drift Speed ◽  
Ice Drift ◽  
Sea Ice Drift ◽  
Ice Strength

Abstract. Sea ice cover and thickness have substantially decreased in the Arctic Ocean since the beginning of the satellite era. As a result, sea ice strength has been reduced, allowing more deformation and fracturing and leading to increased sea ice drift speed. The resulting increased sea ice export is thought to further lower sea ice concentration and thickness. We use the global ocean-sea ice NEMO-LIM3.6 model (Nucleus for European Modelling of the Ocean coupled to the Louvain-la-Neuve sea Ice Model), satellite and buoy observations, as well as reanalysis data over the period from 1979 to 2013 to study this positive feedback for the first time in such detail. Overall, the model agrees well with observations in terms of sea ice extent, concentration and thickness. Although the seasonal cycle of sea ice drift speed is reasonably well reproduced by the model, the recent positive trend in drift speed is weaker than observations in summer. NEMO-LIM3.6 is able to capture the relationships between sea ice drift speed, concentration and thickness in terms of seasonal cycle, with higher drift speed for both lower concentration and lower thickness, in agreement with observations. Sensitivity experiments are carried out by varying the initial ice strength and show that higher values of ice strength lead to lower sea ice thickness. We demonstrate that higher ice strength results in a more uniform sea ice thickness distribution, leading to lower heat conduction fluxes, which provide lower ice production, and thus lower ice thickness. This shows that the positive feedback between sea ice drift speed and strength is more than just dynamic, more complex than originally thought and that other processes are at play. The methodology proposed in this analysis provides a benchmark for a further model intercomparison related to the interactions between sea ice drift speed and strength.

Modelled Stokes drift in the Marginal ice zones of the Arctic Ocean

2020 ◽  
Author(s):  
Jingkai Li
Keyword(s):  
Arctic Ocean ◽  
Chukchi Sea ◽  
Surface Current ◽  
Reanalysis Data ◽  
Stokes Drift ◽  
The Arctic ◽  
Bulk Wave ◽  
Wave Parameters ◽  
The Arctic Ocean ◽  
Ice Floes

<p>The Stokes drift in the marginal ice zones (MIZ) of the Arctic Ocean is modelled by WAVEWATCH III. Applying two viscoelastic and one empirical frequency-dependent wave-ice models, the modelled wave parameters and spectrum are compared with field observations in the Beaufort-Chukchi Sea. Three wave-ice parameterizations show similar abilities to produce the surface Stokes drift estimated from buoy measurements. By using five-year (2015-2019) hindcasted directional spectra of the autumn Arctic, we present and discuss the monthly mean surface Stokes drift (1-10 cm/s), e-folding depth (1-14 m) and vertically integrated transport (0.1-0.4 m2/s) in the marginal ice zones, which are stronger in October than in September. When bulk wave parameters are adopted to estimate the Stokes drift fields, the surface Stokes drift will be underestimated by about 44-59% with mean ice concentration smaller than 60%, and the Stokes e-folding depth will be overestimated by about 1.4 to 5.0 times increasing from the interior to the edge of the ice cover. Since the Stokes drift may be an important component of the total surface current, we compare the modelled surface Stokes drift with the Eulerian current from reanalysis data, which shows that the mean surface Stokes drift is typically about 30% of the Eulerian current over large parts of the MIZ in Arctic Ocean, and is of the same order or even larger in some sea areas of the Chukchi, E. Siberian and Laptev Seas. It indicates that the Stokes drift is necessary to be considered to better model the dynamic processes of the sea ice, especially for the drift of ice floes.</p>

Full Scale Measurement on Level Ice Resistance of Icebreaker

2011 ◽  
Author(s):  
Abdillah Suyuthi ◽  
Bernt J. Leira ◽  
Kaj Riska
Keyword(s):  
Water Resistance ◽  
Open Water ◽  
Full Scale ◽  
Ice Thickness ◽  
Total Resistance ◽  
Conservation Of Energy ◽  
Ship Resistance ◽  
Level Ice ◽  
Ice Resistance ◽  
Ship Speed

This paper presents results from the investigation of ship resistance on first year level ice in the Barent Sea. The basis for the work is the availability of full scale measurement data obtained on board of KV Svalbard in 2007. Measurements were made of the ice thickness, ship speed over ground in addition to setting power. The ice thickness was measured by means of an electromagnetic device, which enables careful selection of the time sequences for which level ice is present. By utilizing Newton II law and conservation of energy, the total resistance can be determined. The ice resistance in level ice was then obtained by subtracting the open-water resistance from the total resistance. The open-water resistance was measured when the ship was traveling in open water during the expedition. The relationship between the ship resistance and the ship speed over ground in level ice was finally obtained and compared with the Lindqvist formulation of estimation of ice resistance.

scholarly journals Ship Resistance When Operating in Floating Ice Floes: A Derivation of Empirical Equations

2020 ◽  
Author(s):  
Luofeng Huang ◽  
Christopher Ryan ◽  
Bojan Igrec ◽  
Andrea Grech La Rosa ◽  
Dimitris Stagonas ◽  
...  
Keyword(s):  
The Arctic ◽  
Empirical Equations ◽  
Ship Resistance ◽  
Open Sea ◽  
Ice Concentration ◽  
Arctic Shipping ◽  
Ice Floes ◽  
Ship Performance ◽  
Propulsion Power ◽  
Ship Speed

Abstract With the effects of global warming, the Arctic is presenting a new environment where numerous ice floes are floating on the open sea surface. Whilst this has unprecedentedly improved Arctic shipping navigability and brought about significant opportunities, the interaction of such floes with ships has yet to be understood, thus hindering appropriate assessment of corresponding ship performance. This paper presents work on developing empirical equations to estimate the effects of such floes on ship resistance. Based on extensive data from validated computational simulations, the ice-floe resistance has been shown to correlate with ship beam, ship speed, ice concentration, ice thickness and floe diameter, and the regression powers of each the parameter on resistance are ascertained for a container ship. This leads to an empirical equation that can immediately predict ice-floe resistance in a given condition. The proposed approach has the potential to facilitate propulsion power estimates for Arctic shipping, as well as providing valuable insights into ship design for these environmental conditions.

Simulation of Ice Force and Breaking Pattern for Icebreaking Ship in Level Ice

2017 ◽  
Author(s):  
Junji Sawamura ◽  
Yutaka Yamauchi ◽  
Keisuke Anzai
Keyword(s):  
Numerical Model ◽  
Model Test ◽  
Ice Thickness ◽  
Broken Ice ◽  
Level Ice ◽  
Ice Force ◽  
Bending Failure ◽  
2D Numerical Model ◽  
Ship Speed ◽  
Good Agreement

A 2D numerical model was proposed to predict the repetitive icebreaking pattern and ice force of an advancing ship in level ice are presented. The numerical model focuses on the icebreaking at the waterline and neglects the broken ice rotating and sliding underwater hull. The repeated ship-ice contact and bending failure of a floating ice along the waterline are evaluated numerically. The computed ice channel width and icebreaking resistance are compared with measured values in the model test. Numerical results show moderately good agreement with the model test data. The effects of ice thickness and ship speed on the icebreaking resistance are investigated numerically. The icebreaking resistance depends on both the ice thickness and ship speed. The ice channel, however, depends on ice thickness, but there is little difference in ship speed.

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