Journal of Cold Regions Engineering

Recently, higher sea surface temperature and less sea ice extents have been reported because the polar environments are dramatically transforming because of climate change. Measurements of sea ice thickness are important for assessing climate change. Thus, it is required to constantly monitor sea ice thickness to accurately measure and estimate the future trends of the polar environment. In this study, the average sea ice thickness in the Arctic Ocean was calculated by using elevation data from a laser rangefinder installed on the icebreaker, RV Araon, operated by Korea Polar Research Institute (KOPRI). The freeboard was calculated by using the elevation data from the top of the bow, and the ice draft was calculated using hydrostatic equilibrium. The results showed that the sea ice thickness increased with higher latitudes and from east to west and the obtained data are expected to be a fundamental basis for the future research of climate change by monitoring the polar region.

Hydropower is a major power source in cold region countries. It is also the largest renewable energy source offering significant potential for reduction in carbon emissions. In Norway, hydropower accounts for nearly 99% of the total electricity production. To meet winter demand, storage schemes are implemented in tandem with run-of-river schemes to a large extent in cold region hydropower systems. In these systems, ice creates operational constraints during winter that can lead to reductions in power production. The problems occur in the various phases of the ice regime, mainly due to frazil ice, ice runs, and ice jams. Counteracting these ice problems is usually a difficult task that involves expensive measures and possibly lost production. This paper presents a comprehensive review of the effects of freshwater ice on hydropower systems. It has been shown that ice in freshwater systems poses a number of operational constraints on the various components of a hydropower system at a time when energy demand is at its peak. The literature review presents a useful baseline for operators of power plants as well as showing problem areas for future research. The trends in the northern areas toward warmer and unstable winters could both alleviate and exacerbate the current challenges for cold climate hydropower operation and the findings of this paper should provide useful background for assessments of future ice impacts.

The authors have compiled information on the fundamentals of open-pit glacier ice excavation from a variety of sources. These sources primarily include U.S. Army technical and scientific studies and peer-reviewed research on glacier ice-excavation activities and the properties and mechanical behavior of ice, but also the relatively few publicly available feasibility studies and environmental impact assessments published by private mining companies. While ice is technically a non-Newtonian fluid over long timescales, the authors suggest that it may be regarded as a low-density and low-strength rock, analogous to coal, for the practical purpose of ice excavation over short timescales. Three distinct ice-excavation techniques are reviewed: blasting, melting, and mechanical excavation, providing a case study of each. The authors summarize the unique advantages and disadvantages of each technique and conclude that an optimal open-ice-pit mining operation would most likely rely primarily on mechanical excavation and secondarily on blasting.

Shear strength is a basic mechanical property of sea ice and directly affects the determination of ice loads on offshore structures in addition to the breakup behavior of ice cover in sea ice dynamics. This paper reports on the writers’ studies of the influences of ice temperature, brine volume, and shear stress rate on sea ice shear strength using laboratory shear tests with single-shear plane and lateral confinement. Ice samples were collected from the Laizhou Bay and Yellow River Delta of the Bohai Sea. Sea ice shear strength increases linearly in accordance with decreasing temperature and increasing shear stress rate, and decreases exponentially in accordance with the square root of brine volume. Considering the influences of both brine volume and shear stress rate comprehensively, this paper presents a double-parameter function to determine the sea ice shear strength.