Sea Ice Thickness Forecast Performance in the Barents Sea

The presence of sea ice has a major impact on the safety, operability and efficiency of Arctic operations and navigation. While satellite-based sea ice charting is routinely used for tactical ice management, the marine sector does not yet make use of existing operational sea ice thickness forecasting. However, data products are now freely available from the Copernicus Marine Environment Monitoring Service (CMEMS). Arctic asset managers and vessels’ crews are generally not aware of such products, or these have so far suffered from insufficient accuracy, verification, resolution and adequate format, in order to be well integrated within their existing decision-making processes and systems. The objective of the EU H2020 project “Safe maritime operations under extreme conditions: The Arctic case” (SEDNA) is to improve the safety and efficiency of Arctic navigation. This paper presents a component focusing on the validation of an adaption of the 7-day sea ice thickness forecast from the UK Met Office Forecast Ocean Assimilation Model (FOAM). The experimental forecast model assimilates the CryoSat-2 satellite’s ice freeboard daily data. Forecast skill is evaluated against unique in-situ data from five moorings deployed between 2015 and 2018 by the Barents Sea Metocean and Ice Network (BASMIN) Joint Industry Project. The study shows that the existing FOAM forecasts produce adequate results in the Barents Sea. However, while studies have shown the assimilation of CryoSat-2 data is effective for thick sea ice conditions, this did not improve forecasts for the thinner sea ice conditions of the Barents Sea.

Guidance Model Representing an Ice Field for Path-Planning in Ice Management

In the work presented in this paper, the problem on how to represent a simplified ice field in a guidance model, enabling path and maneuver planning for IM operation, has been studied. The use of B-splines and other basis functions are considered to represent relevant guidance information over the 2D drifting ice field. A weight value is computed and updated at locations that represents broken ice (visited by an icebreaker) versus unbroken ice. The guidance model will ensure that there is a continuous representation of the state of the ice field during the operations. The drifting behavior of the ice field is incorporated into the guidance model. The model will be updated with new (solid) ice that is formed at the beginning of the ice field, and it will continuously be updated in the path where the icebreaker moves. To simulate the maneuvers of the icebreaker, a dynamic model is used, and the ice breaking effect where the ice field is continuously broken into smaller ice floes is included in the model. This representation of an ice field can be used in a path-planning algorithm to determine the icebreaker path in a moving ice environment in order to reduce the ice field into small enough ice floes and reduce the load on the protected structure.

Do Vessels Remain Within Their Operational Limitations in Ice? Analyzing the Risks of Vessels Operating in the Kara Sea Region Using POLARIS

This study investigates whether the vessels remain within their operational limitations in ice using the risk index calculated based on the Polar Operational Limitations Assessment Risk Indexing System (POLARIS) — an acceptable methodology for the assessment of operational limitations in ice infested waters, referenced in the Polar Code of the International Maritime Organization (IMO). The speeds and positions of the vessels in the Kara Sea region were analyzed from January through April for 2017–2019 using the navigational data provided by the Northern Sea Route Administration. For each vessel, except for the icebreakers, the risk index based on POLARIS was calculated using the open-access ice information that was provided by the Arctic and Antarctic Research Institute in Russia. The variation of risk index was analyzed with respect to various parameters such as the ice-class of the vessel, the reported operating speed of the vessel, and the built year of the vessel. Furthermore, we explored the limitations of the risk assessment system as well as the limitations of the available ice information and its implications on the risk assessment system. This paper reports preliminary results from the analysis.

Extreme Value Estimation of Mooring Loads Based on Station-Keeping Trials in Ice

The purpose of this work is to perform an extreme value estimation of the mooring loads associated with station-keeping of a ship operating in ice. In general, the design of mooring lines is based on estimation of the extreme loading caused by environmental conditions within the relevant area. In March 2017, station-keeping trials (SKT) in drifting ice were performed as part of a project headed by Statoil in the Bay of Bothnia. The objective was to investigate the characteristics of the mooring loads for the supply vessel Magne Viking for different types of physical ice management schemes. Tor Viking was employed as an ice breaker as part of the physical ice management systems. The ice conditions (i.e. the ice drift velocity and the ice thickness) during the trials were monitored by using Ice Profiling Sensors (IPSs). Different patterns of ice-breaking manoeuvers were investigated as part of the physical ice management systems, such as square updrift, round circle, circle updrift and linear updrift pattern were studied as part of the field experiments. The peak values of the mooring loads for the supply vessel are determined by using the min peak prominence method. For the purpose of extreme value prediction, the peak over threshold method and block maxima method for a specific time window are applied to estimate the mooring loads that correspond to specific probabilities of exceedance (or equivalently: return periods). These loads can then be compared to the design loads that are being specified by relevant international standards.

Peridynamic Analysis of Fragmentation of Ice Plate Under Explosive Loading With Thermal Effects

Along with the development in arctic region, the icebreaking technologies are gradually becoming the focus. As one of the most powerful and effective way to breaking ice, especially in the ability to solve ice jams, the study of the behaviour of the sea and river ice under dynamic loads is an urgent subject of scientific research and it attracts extensive attention. In addition, the temperature change in the process of ice failure cannot be neglected since that temperature plays an important role in the mechanical properties of the ice. In this study, a fully coupled thermoelastic ordinary state-based Peridynamic model is employed to investigate fragmentation of ice cover subjected to an underwater explosion. Both the deformation effect on the thermal effects and the thermal effects on deformation are taken into consideration. The pressure shocks generated by the underwater explosion are applied to the bottom surface of the ice cover for non-uniform load distributions. Crack propagation paths are investigated, the damage is predicted and compared with existing experimental results. The corresponding temperature distributions are also examined. Furthermore, the ice failure mode in both the top surface and the bottom surface of the ice sheet is investigated.

Scaling Up of Local Ice Pressures for a Fixed Offshore Platform Based on Ice Basin Model Data

Fundamentals of the similarity theory in the ice deformation mechanics, as well as problems related to scaling up of local ice pressures measured during tests in an ice basin to full scale values are considered. A new scaling principle based on a hypothesis of ice deformation limiting surface isomorphism and direct computer simulation is proposed. An ice-resistant platform, for which local pressures were measured in ice tests and ice pressures were recalculated to full scale values using generated ice deformation limiting surfaces, was considered as an example.

Safe and Fuel-Efficient Voyage Planning for the Northeast Passage by Combining Reliable Ship Performance, Weather and Ice Forecast Models

The Northeast Passage in the Arctic between Europe and Asia offers a significantly shorter voyage compared to the Southern route through the Suez Canal. In 2017, the EU research project “Safe maritime operations under extreme conditions: the Arctic case (SEDNA)” was established to perform a comprehensive analysis of Arctic transit shipping and to promote technical solutions for this purpose. This paper is based on the deliverables of the SEDNA project. A voyage planning tool (VPT) for Arctic applications was developed to plan the optimal route regarding ship’s fuel consumption and safety. One of the most advanced metocean and ice forecast model is utilized to provide comprehensive environmental conditions that are synchronized and will be updated frequently during the voyage. The ship energy system model takes into account the various environmental variables as well as ship’s operational conditions to compute the ship performance in both open and ice infested waters. For Arctic operations, specific ice resistance models are implemented in the VPT, and a user has the options of either relying on icebreaker assistance or going for unassisted navigation in part of the entire Arctic passage. Case study voyages of different ship types, route options, staring time, home/destination ports are simulated to demonstrate how various optimal routes are planned and how the transit time and fuel consumption vary. This information is considered being crucial for ship owners for planning their voyages in advance. The continuously updated voyage information from the VPT is particularly helpful for the ship crew if there are specific ship operations and risk mitigation actions that need to be taken care of during the voyage. In addition, this study underlines that a safe and fuel-efficient Arctic passage requires viable voyage planning tools that combine reliable ship performance with weather and ice forecasts.

Numerical Study of Large Pendulum Ice Impact Loads

The large pendulum ice impact experiments performed at the Memorial University of Newfoundland recorded pressure distributions using a novel high-fidelity measurement device, the Impact Module, which is capable of fine spatial and temporal resolutions — effectively 2 cm2 at 500 Hz. These experiments achieved impact energies approaching 29 kJ, velocities of 4.7 m/s, and loads reaching 620 kN. The data obtained by the device are unique, as the Impact Module is capable of recording ice pressure data with both high spatial and high temporal resolution over a large contact area. Until recently, there was no ice load measurement technique capable of excelling in all these aspects. This work aims to study the simulation of a numerical test panel model under the action of the loads measured during the ice impact experiments. This is done by using a non-linear numerical model with explicit time integration capable of simulating the dynamic transient ice loads and comparing their effects to a quasi-static approach.

Future Scenarios for Arctic Shipping

Maritime activity in the Arctic is on the increase, driven by multiple factors including the development of Arctic natural resources, climate change, regulatory changes, improved technology and operations, national and international policies, infrastructure developments, fuel prices, and the global economy. This article aims to identify and analyze such change drivers and to discuss how these might influence the future of three specific segments of Arctic shipping: destination-Arctic shipping (operation between Arctic and non-Arctic locations), trans-Arctic shipping (operation between non-Arctic locations through Arctic waters), and Arctic cruising. The study finds that each considered segment of Arctic shipping is subject to a unique set of significant change drivers.

Damping of Regular Waves in Model Ice

Wave characteristics change significantly when the waves propagate in a solid ice field. The damping of the incident waves due to the presence of the ice sheet has a significant impact on the modification of wave propagation and dispersion. In this study the interaction of waves with solid ice are investigated by means of model tests. The objective of the study is to measure wave and ice characteristics and analyze the data regarding wave damping and the change of wave parameters in model ice. The experiments were performed in the ice tank of the Hamburg ship model basin (HSVA) with a set of regular waves with varying wave number and steepness. The surface elevation of the waves is recorded by acoustic and motion capturing measurement devices. By comparing the measurements of the incident open water waves with the waves in ice, the change in terms of wave amplitude and dispersion due to the presence of ice is analyzed. It is shown that once the waves travels through the ice the angular frequency remains unchanged while the wave amplitude exponentially decays, with an increasing decay coefficient at smaller wave length. Furthermore, the dispersion relation in ice, represented by the measured angular frequency and wave number, is consistent with the theoretical dispersion relation.