Increased knowledge about sea ice

Increased knowledge about sea ice

Top image: Fieldwork performed on sea ice ridges in 2010. Photo: Lucie Strub-Klein/UNIS.  

Sea ice is the main challenge to the development of oil and gas industries and the exploitation of these resources in the High Arctic. Ships and safe structures should be designed by taking into account sea ice concentration, thickness and strength. Lucie Strub-Klein has studied level ice and sea ice ridges and will defend her PhD thesis on 22 May at UNIS.

18 May 2012
Press release from UNIS and NTNU

The ice loads modeling has progressed the past few years, but there are still some uncertainties regarding the magnitude of ice loads in structures and ships. In the absence of icebergs, ice ridges are the governing factor in Arctic marine design.  Data must be collected on ice properties (thickness as well as temperature, salinity, density and strength) for more accurate modeling. In addition, the consolidation and aging process of sea ice ridges is yet not well understood (e.g. in the Fram Strait).

Lucie Strub-Klein has studied these elements for her PhD thesis. The study locations were Van Mijenfjorden, Van Keulenfjorden, the Barents Sea (near Hopen) and the Fram Strait.

Level ice and sea ice ridges
Strub-Kleins PhD research was divided into two parts: the study of level ice and the study of sea ice ridges.

The level ice studies aimed at getting a better understanding the variation of sea ice strength through and across the ice sheet and how it changes with time. An important finding was that the variability of the uniaxial compressive strength is strongly related to the localization of the brine (pockets and channels) in the sea ice.

She also established a statistical distribution for the uniaxial compressive strength by using more than 1000 samples, collected from 2005 to 2011, in addition to studying the propagation of stresses in sea ice. The stresses were expressed as a function of the distance.

The ridges studies aimed at studying the evolution of first- and second-year ridges. It was observed that the water below the level is involved in the desalination process and that small ridges of landfast ice should erode faster in tidal currents than larger ridges. Strub-Klein also gathered and improved the knowledge on the morphology of first-year sea ice ridges. A very large amount of published data was collected and analyzed in what is the biggest catalogue and review on the morphological properties of first-year floating ice ridges published until now.

Important correlations between the ridge dimensions were established and the study of the spatial variation of the consolidated layer showed that ridges grew evenly in width. She also studied the consolidation and the transition from first-year to second-year ridges in the Fram Strait

Dissertation
Lucie Strub-Klein will defend her PhD thesis entitled “Field measurements and analysis of the morphological, physical and mechanical properties of level ice and sea ice ridges” on Tuesday 22 May at 13:15. She will give a trial lecture entitled ”Dynamics of Sea Ice and Ice-Ocean Coupling ” the same day at 10:15.

Lucie Strub-Klein.

Lucie Strub-Klein.

About the candidate
Lucie Strub-Klein was born in Schiltigheim (Strasbourg) in France in 1984.

She studied civil engineering at The National Institute for Applied Science (INSA) in Strasbourg with a specialization in construction, steel and concrete design, bridge design, material properties.

She completed her Master’s degree in sea ice rheology at INSA in cooperation with UNIS.

In August 2007 she started her PhD work at UNIS and NTNU.

 

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