Sea Ice

Brine Networks in Sea Ice

NSF Office of Polar Programs

Sea ice is the boundary layer between the ocean and the atmosphere in polar regions. It is not a solid interface, as it might seem, but a very porous one, that controls the exchange of heat, fluid, gases, and chemical species between the ocean and atmosphere. Because of this, sea ice plays an enormous role in global climate and ocean circulation. The Arctic is losing multiyear (thick) sea ice cover at a rate of as much as 15% per decade, and it is being replaced by thinner, more porous, annual sea ice, that forms in winter and completely melts in summer. This has implications for climate change (its a positive feedback), as well as for wildlife, commerce, and even geopolitics in the Arctic region. Our work involves field work, engineering (design and development of the ICE-MITT system) and the use of applied mathematics to characterize the topology of brine networks in sea ice (Scott Pauls of the Math department is my co-PI). Until we can get the sea ice to the lab with its original pore structure intact, we can't accurately model that structure. The results of our work will help climate modelers, oceanographers, and even biologists understand how pore networks are organized in sea ice and the role they play in the local, regional, and global environments - they affect sea ice melt rate, ocean-atmosphere heat exchange and temperature (which drives circulation), photosynthetic marine biota and the higher food web that depends on it, and even the distribution and fate of pollutants. This project is also important to our educational mission. It has already provided numerous opportunities for Thayer students to work on a real and complex engineering project, and will provide future opportunities for Dartmouth students in field research, communication of science, and applied math.





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