Role of radiative forcing on the sea ice melt-growth cycle in a changing Arctic marine environment

点击翻译按钮获取中文摘要

The Arctic sea ice cover is in rapid decline due to global warming with yet another new record low reached in September 2012. The diminishing ice cover is having a discernible impact on the polar marine environment. However, the extent of this impact on future changes to climate, carbon cycling and ecosystems remains uncertain. At the root is how surface radiative forcing affects changes in sea ice properties, and how these changes in turn modulate the forcing. Such interactions form the base of complex climate feedbacks operating in the Arctic. Considering the vastness of the area of sea ice (~10 million km2 or roughly the size of Canada) that forms and then melts each year, the importance of a comprehensive understanding of the processes driving this cycle cannot be overstated. Given this, the objectives to be addressed in the proposed research are to investigate 1) the reciprocal feedbacks between radiative forcing and the melt evolution of the sea ice surface, 2) how small-scale interactions with the porous sea ice structure and imbedded impurities affect radiative transfer within the sea ice interior, and 3) the importance of variable under-ice radiation fields and optical properties on water column heating and sea ice melt rates. These three objectives will help answer questions about how sea ice melt is partitioned between surface, interior and bottom, and how much heat is retained in the upper ocean layers where it can cause a delay in the fall freeze-up. Our ability to predict future climate rests on understanding these processes. The objectives are interrelated, yet individually provide suitable and distinct projects for both MSc and PhD studies. This research will advance our knowledge of sea ice processes and climate feedbacks, train new students in Arctic environmental research and ultimately, benefit northerners by improving climate predictions that will help communities and various levels of government adapt to climate change.