Sea Ice Engineering theory and application Claude Daley Sea Ice Engineering 2017 –Notes ii © Claude G. Daley 2017 With components developed by D.B.Colbourne and B.W.T. Quinton All rights reserved. No reproduction, copy or transmission of this publication may be made without written permission. This draft is solely for the use of students registered in EN8074 and EN9096, in Winter 2016. All enquiries to: C.G. Daley Faculty of Engineering and Applied Science Memorial University of Newfoundland St. John’s Newfoundland and Labrador Canada A1B 3X5 Email: [email protected] Note: images, sketches and photo's are © C. Daley unless otherwise noted Cover image by C. Daley from GEM Simulation Program Sea Ice Engineering 2017 –Notes iii …………………………………… Contents Acknowledgments ........................................................................................................................... vi 1 Introducing Arctic Offshore Engineering ................................................................................ 1 1.1 Overview ......................................................................................................................... 1 1.2 Basics .............................................................................................................................. 1 1.3 Current Arctic Engineering Activities ............................................................................ 3 1.4 Transportation ................................................................................................................. 4 1.4.1 North West passage......................................................................................... 4 1.4.2 Northern Sea Route ......................................................................................... 5 2 Physical properties of ice ......................................................................................................... 7 2.1 Properties of Water ......................................................................................................... 8 2.2 Hydrogen bonding......................................................................................................... 10 2.2.1 Water Clusters ............................................................................................... 10 2.3 Freezing ......................................................................................................................... 10 2.4 Anomalous properties of water ..................................................................................... 11 2.4.1 Density .......................................................................................................... 11 2.4.2 Boiling Point ................................................................................................. 12 2.5 Crystal structure of Ice .................................................................................................. 13 2.6 Bond Deformation in Ice crystals ................................................................................. 15 2.7 Ice Impurities ................................................................................................................ 16 2.8 Microstructure of ice ..................................................................................................... 17 2.9 Table of properties ........................................................................................................ 18 3 Ice Formation at Sea .............................................................................................................. 19 3.1 Types of Sea Ice ............................................................................................................ 19 3.1.1 New Ice Types .............................................................................................. 19 3.1.2 Nilas .............................................................................................................. 19 3.1.3 Young Ice ...................................................................................................... 19 3.1.4 First-year Ice ................................................................................................. 20 3.1.5 Old Ice ........................................................................................................... 20 3.2 Initial Ice Formation...................................................................................................... 21 3.3 First Year Ice ................................................................................................................. 24 3.4 Temperature Profiles through First-Year Ice ................................................................ 28 3.5 Ideal Growth of Clear Ice .............................................................................................. 29 3.6 Ideal Growth of Ice with Snow ..................................................................................... 32 3.7 Actual Growth of Ice ..................................................................................................... 33 3.8 Gas and Brine Pockets .................................................................................................. 34 4 Ice Evolution at Sea ............................................................................................................... 37 4.1 Formation of First Year Ridges .................................................................................... 37 4.2 Ice Melting Process ....................................................................................................... 39 4.3 Second-Year Ice ............................................................................................................ 40 4.4 Multi-Year Ice ............................................................................................................... 41 Sea Ice Engineering 2017 –Notes iv 4.5 Multi-Year Ridges......................................................................................................... 42 4.6 Differences in Arctic and Antarctic Sea Ice .................................................................. 44 4.6.1 Thickness ...................................................................................................... 45 4.6.2 Patterns of Ice Extent .................................................................................... 45 4.6.3 Arctic Ice Circulation .................................................................................... 46 4.6.4 Antarctic Ice Circulation ............................................................................... 48 4.7 Wave and Ice Interactions in Marginal Ice Zones ........................................................ 49 4.7.1 Characterization of sub-zones ....................................................................... 50 4.7.2 Wave Attenuation in Marginal Ice Zones ..................................................... 51 4.8 Ice accretion .................................................................................................................. 54 4.8.1 Spray ice........................................................................................................ 54 4.8.2 Atmospheric icing ......................................................................................... 54 5 Icebergs .................................................................................................................................. 56 5.1 Iceberg Formation ......................................................................................................... 56 5.2 Antarctic Icebergs ......................................................................................................... 56 5.3 Arctic icebergs .............................................................................................................. 57 5.4 Iceberg structure ............................................................................................................ 58 5.5 Iceberg size and shape ................................................................................................... 58 5.6 Erosion and melting ...................................................................................................... 59 5.7 Iceberg distribution and drift trajectories ...................................................................... 60 5.8 Iceberg scour and sediment transport ............................................................................ 62 6 Mechanical strength of sea ice ............................................................................................... 63 6.1 Uniaxial Compressive Strength of Ice .......................................................................... 63 6.1.1 Influence of strain rate .................................................................................. 64 6.1.2 Influence of temperature on creep ................................................................ 65 6.1.3 Influence of grain size ................................................................................... 65 6.1.4 Influence of temperature on strength of sea ice ............................................ 66 6.2 Fracture of Polycrystals ................................................................................................ 68 6.3 Other Measures of Ice Strength .................................................................................... 69 6.3.1 Tensile Strength ............................................................................................ 69 6.3.2