Sea-Ice Observation: Advances and Challenges

Abstract

The presence and characteristics of the relatively thin ice cover of Earth’s oceans at high latitude are important determinants of the polar climate and of the polar role in the global climate system. The focus of this chapter is the observation of sea ice. Advances in polar ocean science have been critically dependent on technology to provide the means for frequent and detailed observation of sea ice. The Arctic Climate System Study was an opportunity for a productive coordinated application of existing technology to the study of the marine cryosphere and provided impetus for the development and evaluation of new techniques. The chapter begins with a brief summary of the knowledge of global sea ice in the early 1990s and of the contemporary capabilities for sea ice observation. This introductory section is as a back drop against which to view the continued improvements in observational capability and knowledge associated with ACSYS during the 1990s. The chapter includes discussion of new developments in observational technology, of new activity in ice research and reconnaissance and of new understanding of sea ice. It has been organized around the structure of the original ACSYS science plan which had six process-oriented elements – sea ice extent and concentration, drift, thickness, export to temperate oceans, atmosphere-ice-ocean interaction, sea-ice mechanics – and one geographic element – sea ice of the southern hemisphere. The chapter concludes with a list tangible deliverables from the Arctic Climate System Study in relation to sea ice and a discussion of some key tasks for the future. These topics remain highly relevant in view of the present continued rapid rate of change in polar climate.