ABSTRACT

Sea-ice research has made great progress over the past thirty to forty years due in large part to improved measurements arising from earth observing satellites and year-long continuous measurements of the underside of sea ice from below using subsurface instrumented moorings. The geometry of sea-ice is highly variable and complex with horizontal scale sizes of discrete sea-ice floes ranging from one meter or less to 50 km or more. The vertical scale size, or ice thickness, which is much harder to measure, ranges from 5 cm or less to over 50 m. Sea-ice motion is highly dynamic within the Arctic as indicated by large spatial variations over distance scales ranging from tens of meters to several thousand kilometers (basin scale) as well as on seasonal and interannual time scales. Large internal ice stress conditions can develop which result in the cessation of sea-ice motion which can also impede ship movements through the sea-ice. Given the highly deformed and fractured nature of the floating sea-ice cover, very different responses to nearly identical wind forcing of sea-ice floes can occur over distances as small as a few kilometers. The improved understandings of the sea-ice regime as realized from past, present, and future Arctic research, is essential to realizing the goal of safe and sustainable Arctic activities.

INTRODUCTION

The purpose of this paper is to provide a review and update of sea-ice research including recent findings. The paper also summarizes the outstanding sea-ice research issues which are important to Arctic development activities.

The motivation for sea-ice research has always involved geographic and scientific exploration of the vast and largely unknown Arctic, combined with national security and sovereignty dating back to the middle of the last century. In the latter part of the 20th century, sea-ice research broadened to address the needs of offshore oil and gas exploration and production (Hamilton, 2011). As the sea-ice extent in the Arctic has been reduced over the past two decades, the shipping season for passages through the Arctic has been expanded along its continental margins through the Northern Sea Route off Russia and the Northwest Passage off Canada and the United States. Commercial shipping by ice-class vessels is already becoming more common, especially via the Northern Sea Route off Russia, and the prospect of shipping directly across the central Arctic Ocean is also being contemplated within the next few decades (Smith and Stephenson, 2013). To support Arctic shipping, sea-ice research is required for the development of safe and efficient shipping using these sea routes. In addition, sea-ice research is being conducted to study and better support the use of the Arctic by indigenous peoples who have traditionally used sea-ice as a means of transportation for subsistence hunting and travel based on the extensive traditional knowledge of sea-ice.

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