Journal of Cold Regions Engineering

Several factors are increasing the likelihood of open ice pit mining adjacent to the Greenland ice sheet. This study employs a fully transient one-dimensional (1D) (depth-averaged) ice flow model, which includes a first-order longitudinal stress gradient approximation, to estimate the ice excavation required to establish and maintain an open ice pit. An idealized open ice pit geometry and purely deformational flow are assumed. A Monte Carlo approach is used to quantify the cumulative uncertainty in total ice excavation resulting from four key parameters: (1) ice temperature, (2) ice thickness, (3) equilibrium line altitude, and (4) surface mass balance gradient. Two scenarios of ice pit slope (2H:1V and 3H:1V), excavation method (constant and progressively steepening slope), and surface ablation enhancement ($+25$ and $+50\%$), are considered. Total ice excavation is more sensitive to parameters controlling deformational velocity (1 and 2) than parameters controlling surface mass balance (3 and 4). Enhancing surface ablation by a feasible amount offers the potential to decrease total ice excavation by $\sim 10\%$ over mine life. Progressively steepening the ice pit slope offers the potential to limit variability in ice excavation rate, and reduce velocity and ice thickness gradients conducive to crevasse formation.

In this paper, a finite element analysis (FEA) model of seven span continuous conductors and insulators for an ultra high voltage (UHV) transmission line in a heavy icing area was established for ice shedding analysis. The parameters considered in the ice shedding simulation analysis include damping ratio, ice shedding ratio, ice shedding modes, and ice thickness. The dynamic responses including jumping heights, unbalanced tensions, and vertical loads at the end of the insulator were obtained. The effects of each of the parameters on the dynamic responses were discussed. The design values for unbalanced tensions and vertical loads were proposed for the UHV suspension tower in a heavy icing area based on the analyses results. The dynamic magnification factors of the vertical load should be between 1.06 and 1.11. For the suspension tower in 20 and 30 mm icing areas, the uplift load percentage is proposed to be 10%. For the suspension towers in 40 and 50 mm icing areas, the uplift load percentage is proposed to be 5%.

A mathematical model is developed to describe changes in ice volume in the cryosphere. Modeling the cryosphere may be useful in assessing future climate impacts currently captured by global circulation models (GCMs) by providing an opportunity to validate GCMs. Leveraging the dominating effects of freezing and thawing in the cryosphere to simplify relevant heat transport equations allows for the derivation of a mathematical model that can be solved exactly. Such exact solutions are useful in investigating other climatic components that may be similarly analyzed for possible GCM validation. The current trend in GCM advancement is to increase the complexity and sophistication of the various heat transport effects that are represented in the governing mathematical model in cumulative form as the heat forcing function. In this paper, simplified models are developed whose solution can be directly compared with available data forms representing temperature and ice volume during the Pleistocene. With careful integration of the Pleistocene temperature term in the mathematical solution, the well-known cumulative departure method can be resolved from the mathematical solution using a two-term expansion of the corresponding Taylor series. This simplification is shown to be a good approximation of the Pleistocene ice volume for given Pleistocene temperatures.