How the Arctic Ocean Drives Ice Melt
A group of more than two dozen international researchers gathered at a Chapman Chair March 2013 workshop to tackle the question of whether the increasing warmth of the Arctic Ocean itself is melting its own cover of ice. The results were published in December in the Bulletin of the American Meteorological Society.
Chapman Chair 2006-2015
Eddy Karmack’s research has addressed four broad categories: (1) water mass formation, thermohaline circulation, mixing, shelf dynamics and freshwater budgets; (2) evidence and impacts of climate variability in subarctic and arctic seas; (3) the role of the changing physical environment on biogeochemical processes; and (4) dynamics of deep and riverine lakes .
High-latitude water mass formation, thermohaline circulation, mixing, shelf dynamics and freshwater budgets: Papers in the 1970s focused on the formation of bottom waters in the Greenland Sea (a precursor to North Atlantic Deep Water) and in the Weddell Sea (a precursor to Antarctic Bottom Water). Papers in the 1980s focused on the Arctic Ocean’s halocline and interaction; its thermohaline circulation and connection to the North Atlantic; and on its freshwater budget and links to the global thermohaline circulation. More recent efforts have addressed the pathways of water masses entering and exiting the Arctic Ocean, the joint roles of ice melt and river run-off on Arctic stratification, the circulation of Pacific and Atlantic derived waters within the Arctic Ocean, primary production and acidification. Co-authored papers have advanced understanding of ice-covered continental shelves and the dynamics of ice-covered systems to better understand the potential impacts of resource development in the North and consequences to Northern residents. Researches have been carried out on water mass distributions, shelf-break variability, buoyancy partitioning and polynya dynamics. Research and overviews of the Canadian Beaufort Shelf explored potential impacts of climate variability on living resources, including recent overviews on the Northwest Passage and the panarctic shelf system. Research also includes transport processes in the subarctic Pacific Ocean, Sea of Okhotsk and the subarctic Atlantic. Collectively, these works allow application to socially relevant climate change and contaminant transport issues.
Processes, evidence and impacts of climate variability: Collaborative works have documented the Arctic Ocean’s role in global climate: co-authored papers were among the first to report the recent basin-scale warming of Atlantic waters the Arctic Ocean’s Atlantic layer; to show evidence for inter-basin shifts in the Arctic Ocean’s water mass structure; and to explore the role of the Pacific waters on ice cover retreat and biological processes. Work which has followed these initial findings to (a) advance a mechanism of basin-wide water mass transition involving rapid transport of new water around the basin perimeter by boundary currents followed by penetration into the basin interior by double-diffusive intrusions; (b) discuss the impacts of Arctic climate variability on biota and ice cover; (c) explore the mechanisms of interbasin connectivity viz the subarctic/arctic connection.
Physical processes affecting biology and geochemistry: Research here has examined linkages between the physical environment and biogeochemical distributions, rates and processes, including nutrient cycling, primary production, molecular diversity, hypoxia and acidification. Recent work includes application of resilience concepts to high-latitude marine systems.
Circulation, convection and nutrient cycling in deep and riverine lake systems: Papers and reports have been published on lake dynamics. Researches have included the dynamics of ice-covered lakes and rivers, and have been linked to issues involving lake productivity and resource development. A major goal has been to substantially advance understanding in the subject of convective overturn in deep lakes. A series of co-authored papers first describe and then model the thermobaric instability as mechanism of convective overturn in deep lakes, a mechanism of significance to primary production in deep, salmonid lakes. More recent papers (a) predict circulation in Antarctic Lake Vostok, based solely on dynamic and thermodynamic principles and (b) explore the link between lake turnover and nutrient supply.