The marine cryosphere includes all forms of sea ice and its snow cover, icebergs, and floating ice shelves.
MarC Central Questions:
- What are the present mean states, natural variability, and recent trends in sea-ice characteristics in both hemispheres, and what are the physical processes that determine these. How will sea ice respond in future to a changing climate; e.g., will the Arctic Ocean be ice free in summer in the 21st century?
- How will a changing sea-ice cover affect climate through its interactions with the atmosphere and ocean?
- How do processes of ice-ocean interaction, including basal melt and marine ice accretion, affect the mass balance and stability of ice shelves?
- What is the role of the seasonal production of sea ice in the neighbourhood of ice shelves in driving currents beneath the shelves and thereby influencing basal melting and re-freezing?
- What is the distribution and variability of fresh water input to the oceans from ice shelves, icebergs and ice sheet runoff, and what role does this have on ocean circulation (e.g., maintenance of global thermohaline circulation)?
The primary objective of this theme is to improve our understanding of the ocean-ice-atmosphere system in the polar regions through enhanced observations, process studies and models. This includes the dynamics and thermodynamics of sea ice and its snow cover, changes in the thickness distribution and characteristics of these media, polynya processes, the impact of sea ice on water mass modification (addition of brine during sea-ice formation, freshening during melt), and interactions of sea ice and snow with the atmosphere. In addition, ice shelf-ocean interactions, the role of ice shelves and icebergs in the ocean freshwater budget, and the impact of changes in sea ice and ice shelf properties that may affect thermohaline circulation lay within this objective.
