U.S.-New Zealand Cooperative Research: Nuclear Magnetic Resonance Study of Antarctic Sea Ice Morphology

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9726777 Seymour This award supports collaborative work between Dr. Joseph D. Seymour, Department of Chemical Engineering and Materials Science, University of California at Davis, and Professor Paul T. Callaghan, Department of Physics, Massey University, New Zealand. This project will take a Nuclear Magnetic Resonance (NMR) spectrometer which operates in the Earth's magnetic field, to Antarctica to measure brine content and brine diffusion within first year sea ice of McMurdo sound. The objective is to obtain a second season (1st season, NZAP Event K131, Oct.-Nov. 1995) of NMR data to validate prior results, provide sampling of seasonal ice variation and establish a correlation between NMR measurements, ice structures and traditional optical microscopy data. In addition, a system in which a magnet is placed in a bore hole in the ice will be tested, a technique new to the principal investigator. Time in New Zealand will be used to complete data analysis on extensive laboratory NMR microscopy measurements made during the PI's NSF postdoctoral tenure (1995-1996, Massey University) and prepare a manuscript on the laboratory and field studies. The laboratory data includes three dimensional images of brine channel structure and spatially resolved measurements of the diffusion tensor. The diffusion data provide the direction and magnitude of brine mobility, of use in understanding convective heat transport in sea ice. This is the first use of NMR microscopy to quantitatively characterize NaCI/sea ice structure. The project is the only application of field NMR methods to polar research being pursued and represents validation of NMR as a field instrument for environmental measurements.