Sea Ice

David N. Thomas

• Publisher: Wiley-Blackwell
• Year: 2016
• Print ISBN: 9781118778388
• eBook ISBN: 9781118778357
• Edition: 3
• Topic: Biological Sciences
• Subtopic: Ecology
• Index: Biological Sciences

Over the past 20 years the study of the frozen Arctic and Southern Oceans and sub-arctic seas has progressed at a remarkable pace. This third edition of Sea Ice gives insight into the very latest understanding of the how sea ice is formed, how we measure (and model) its extent, the biology that lives within and associated with sea ice and the effect of climate change on its distribution. How sea ice influences the oceanography of underlying waters and the influences that sea ice has on humans living in Arctic regions are also discussed.  

Featuring twelve new chapters, this edition follows two previous editions (2001 and 2010), and the need for this latest update exhibits just how rapidly the science of sea ice is developing. The 27 chapters are written by a team of more than 50 of the worlds' leading experts in their fields. These combine to make the book the most comprehensive introduction to the physics, chemistry, biology and geology of sea ice that there is.

This third edition of Sea Ice will be a key resource for all policy makers, researchers and students who work with the frozen oceans and seas.

Chapter 1
Overview of sea ice growth and properties

Chris Petrich¹ and Hajo Eicken²

¹Northern Research Institute Narvik, Narvik, Norway

²University of Alaska Fairbanks, Fairbanks, AK, USA

1.1 Introduction

A recent, substantial reduction in summer Arctic sea ice extent and its potential ecological and geopolitical impacts generated a lot of attention in the media and among the general public. The satellite remote-sensing data documenting such recent changes in ice coverage are collected at coarse spatial scales (Chapter 9) and typically cannot resolve details finer than about 10km in lateral extent. However, many of the processes that make sea ice such an important aspect of the polar oceans occur at much smaller scales, ranging from the sub-millimetre to the metre scale. An understanding of how large-scale behaviour of sea ice monitored by satellite relates to and depends on the processes driving ice growth and decay requires an understanding of the evolution of ice structure and properties at these finer scales and this is the subject of this chapter.

The macroscopic properties of sea ice are of interest in many practical applications discussed in this book. They are derived from microscopic properties as continuum properties averaged over a specific volume (representative elementary volume) or mass of sea ice. This is not unlike macroscopic temperature and can be derived from microscopic molecular movement. The macroscopic properties of sea ice are determined by the microscopic structure of the ice, i.e. the distribution, size and morphology of ice crystals and inclusions. The challenge is to see both the forest (i.e. the role of sea ice in the environment) and the trees (i.e. the way in which the constituents of sea ice control key properties and processes). In order to understand and project how the forest will respond to changes in its environment, we have to understand the life cycle of its constituents, the trees. Here, we will adopt a bottom-up approach, starting with the trees, characterizing microscopic properties and processes and how they determine macroscopic properties, to lay the groundwork for understanding the forest. In using this approach, we will build up from the sub-millimetre scale and conclude with the larger scales shown in Figure 1.1.

Figure 1.1 Ice types, pack ice features and growth, melt and deformation processes.

Figure 1.2 Surface appearance and microstructure of winter lake ice (Imikpuk Lake, top, panels a–d) and sea ice (Chukchi Sea landfast ice, bottom, panels e–h) near Barrow, Alaska. The bright features apparent in the lake ice are cracks that penetrate all the way to the bottom of the ice cover (close to 1m thick), while the clear, uncracked ice appears completely black (a, top). (e) The sea ice surface photograph shows a network of brine channels that join into a few feeder channels. (b, c, f, g) Photographs of vertical thin sections from the two ice covers, with (b) and (f) recorded between crossed polarizers, highlighting different ice crystals in different colours. Panels (c) and (g) show the same section as (b) and (f) in plain transmitted light, demonstrating the effect of brine inclusions on transparency of the ice. (d, h) Photomicrographs showing the typical pore structure at a temperature of −5°C (lake ice) and −15°C (sea ice), with few thin inclusions along grain boundaries in lake ice (d) and a network of thicker brine inclusions in sea ice (h).

Sea ice would not be sea ice without salt. In fact, take away the salt and we are left with lake ice, differing in almost all aspects that we discuss in this chapter. The microscopic and macroscopic redistribution of ions opens the path to understanding all other macroscopic properties of sea ice. We will therefore start in Section 1.2 by looking at the influence of ions on ice growth at the scale of individual ice crystals, in sea ice growing under both rough and quiescent conditions. We will continue in Section 1.3 by looking at the dynamic feedback system between fluid dynamics and pore volume, both microscopically and at the continuum scale. We will point out that our knowledge is far from exhaustive in this fundamental aspect. However, armed with a basic understanding of crystal structure, phase equilibria and pore structure, we can shed light on ice optical, dielectric and thermal properties and macroscopic ice strength in Section 1.4. One of the most discussed aspects of sea ice is its presence or absence. We wi...

Table of contents

• Cover
• Title Page
• Copyright
• Table of Contents
• List of contributors
• Preface
• Chapter 1: Overview of sea ice growth and properties
• Chapter 2: Sea ice thickness distribution
• Chapter 3: Snow in the sea ice system: friend or foe?
• Chapter 4: Sea ice and sunlight
• Chapter 5: The sea ice–ocean boundary layer
• Chapter 6: The atmosphere over sea ice
• Chapter 7: Sea ice and Arctic Ocean oceanography
• Chapter 8: Oceanography and sea ice in the Southern Ocean
• Chapter 9: Methods of satellite remote sensing of sea ice
• Chapter 10: Gaining (and losing) Antarctic sea ice: variability, trends and mechanisms
• Chapter 11: Losing Arctic sea ice: observations of the recent decline and the long-term context
• Chapter 12: Sea ice in Earth system models
• Chapter 13: Sea ice as a habitat for Bacteria, Archaea and viruses
• Chapter 14: Sea ice as a habitat for primary producers
• Chapter 15: Sea ice as a habitat for micrograzers
• Chapter 16: Sea ice as a habitat for macrograzers
• Chapter 17: Dynamics of nutrients, dissolved organic matter and exopolymers in sea ice
• Chapter 18: Gases in sea ice
• Chapter 19: Transport and transformation of contaminants in sea ice
• Chapter 20: Numerical models of sea ice biogeochemistry
• Chapter 21: Arctic marine mammals and sea ice
• Chapter 22: Antarctic marine mammals and sea ice
• Chapter 23: A feathered perspective: the influence of sea ice on Arctic marine birds
• Chapter 24: Birds and Antarctic sea ice
• Chapter 25: Sea ice is our beautiful garden: indigenous perspectives on sea ice in the Arctic
• Chapter 26: Advances in palaeo sea ice estimation
• Chapter 27: Ice in subarctic seas
• Index
• End User License Agreement