Medium-scale experiment in consolidation of an artificial sea ice ridge in Van Mijenfjorden, Svalbard

Evgenii Salganik,Knut Vilhelm Høyland,Aleksey Shestov

doi:10.1016/j.coldregions.2020.103194

Evgenii Salganik, Knut Vilhelm Høyland + Show 1 more

Open Access

https://doi.org/10.1016/j.coldregions.2020.103194

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Abstract

This study characterizes a consolidation of undeformed level ice and ice ridges. Field investigations were performed in the Van Mijenfjorden, Svalbard for 66 days between February and May of 2017. The thickness and properties of the level ice that was used to make the ridge were measured, and thermistor-strings were installed in the ridge and the neighboring level ice. The ridge was visited four times for drilling and sampling. During our field experiment, the level ice (LI) grew from 50 to 99 cm, the consolidated layer (CL) grew up to 120 cm, and the ridge initial macroporosity was about 0.36. The experimental results provided enough information for accurate growth prediction and validation of ridge consolidation models.Two analytical resistive models and two-dimensional discretized numerical models are presented. All models need general met-ocean conditions and general ice physical properties. The ridge model includes the effect of the inhomogeneous top and bottom surfaces of the consolidated layer. The models were validated against the field measurements, and the further details of the analytical models were validated against the numerical model.The analytical resistive ridge model with convective atmospheric flux captures the relevant phenomena well and could be used for prediction of the consolidated layer thickness in probabilistic analysis of ice actions on structures. The model including the radiative terms predicted heat fluxes in level ice and ridge better than the convective model but required more input data. Vertical temperature profiles through the consolidated layer and further into respectively a void and an ice block may result in significantly different estimations of the consolidated layer thickness. The difference between fresh and saline ice growth is becoming significant only during the warming phase due to significant change of sea ice microporosity.

Highlights

According to the definition of the World Meteorological Organiza tion (WMO Sea-Ice Nomenclature, 1971), an ice ridge is a line or wall of broken ice forced up by pressure
We will focus on thermodynamic effects from the main differences between level ice and ice ridge including ridge sail, snow on its top, ridge rubble, and ridge inhomogeneity (Section 4.1)
We will describe details of the consolidation experiment and how general conclusions can help with its analysis and model validation (Sections 4.2–4.5)

Summary

Introduction

According to the definition of the World Meteorological Organiza tion (WMO Sea-Ice Nomenclature, 1971), an ice ridge is a line or wall of broken ice forced up by pressure. Ridges usually consist of three parts: the sail, the consolidated layer, and the unconsolidated rubble. The thickness of level ice, the consolidated layer, and the keel depth are the main ridge parameters for ice action calculations. The level ice hi and the consolidated layer hc thicknesses can be measured by mechanical or thermal drilling or from the ridge vertical temperature profile. It is beneficial if hi and hc can be predicted based on models with general met-ocean data as input. Simple analytical models have the advantage of being applicable in the prob abilistic approach for ice action and evaluation of structural reliability

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Discussion

Conclusion