M - O
MULTITRACER
The salt content of sea ice is a major control on many climatically and biologically relevant processes (e.g., summer melting rates and surface albedo, the equilibrium thickness of multi-year ice, the formation of the brine channels that harbor microbial life in sea ice, the regulation of carbon fluxes between the atmosphere and ocean by maintaining brine network connectivity, the sea ice mechanical strength and, radiation scattering within the ice). In this project, we propose to measure and model delta O18 and Lead-210 vertical profiles (together with internal temperature and salinity) to study heat and brine fluxes through sea ice; two processes that are crucial for a better understanding of ice growth and melt dynamics. A unique aspect of the proposed work is that we will incorporate tracer transport and fractionation into models of sea ice growth and melt. Towards this end, we propose to collect ice cores during the overwintering of the Amundsen ice breaker (Flaw Lead Polynya project), and to measure vertical profiles of temperature salinity, delta O18, and Lead-210 within each core. Tracer transport capabilities will be added to current dynamically and thermodynamically rigorous models of sea ice evolution. The modelled tracer profiles will then be used to reconstruct delta O18 values of the surface ocean along the past trajectory of the sea floe, and potential pollutant transport pathways within the Arctic Ocean. This proposal directly addresses the following major International Polar Year (IPY) objectives: (1) to advance our understanding of polar-global interactions by studying tele-connections on all scales, (2) to quantify, and understand, past and present environmental and human change in the polar regions in order to improve predictions, (3) to determine the present environmental status of the polar regions by quantifying their spatial and temporal variability, (4) to investigate the unknowns at the frontiers of science in the polar regions. Summary provided by http://classic.ipy.org/development/eoi/proposal-details.php?id=322