Oil spills in the Arctic are becoming more likely as shipping traffic increases in response to climate-related sea ice loss. To improve oil spill detection capability, we used a controlled mesocosm to analyze the multipolarized C-band backscatter response of oil in newly formed sea ice (NI). Artificial sea ice was grown in two cylindrical tubs at the Sea-ice Environmental Research Facility, University of Manitoba. The sea ice physical characteristics, including surface roughness, thickness, temperature, and salinity, were measured before and after oil injection below the ice sheet. Time-series C-band radar backscatter measurements detected the differences in the sea ice evolution and oil migration to the sea ice surface in the oilcontaminated tub, which was compared to uncontaminated ice in a control tub. Immediately prior to the presence of oil on the ice surface, the copolarized backscatter is increased by 13-dB local maximum, while the cross-polarized backscatter is decreased by 9-dB. Ice physical properties suggest that the local backscatter maximum and minimum, which occurred immediately before oil migrated onto the surface, were related to a combination of brine and oil upward migration. The findings of this work provide a baseline data interpretation for oil detection in the Arctic Ocean using current and future C-band multipolarization radar satellites.
The ground states of 2-fluorophenol (2FPh) and 3-fluorophenol (3FPh) and their 13 C isotopologues were investigated using Fourier transform microwave (FTMW) spectroscopy in the range of 6 to 26 GHz. Two planar conformers were observed for 3FPh, corresponding to cis and trans orientations of OH relative to F, while only the cis conformer of 2FPh was detected.The rotational constants determined were used to derive substitution (rs) and effective ground state (r0) structures of the lowest energy conformer of each compound: cis-2FPh and trans-3FPh.Geometry optimization at the MP2/6-311++G(2d,2p) level provided equilibrium (re) structures which are in close agreement with the experimental parameters. The derived structures along with results from natural bond orbital (NBO) calculations provide evidence of an intramolecular interaction in cis-2FPh between the fluorine atom and OH moiety that stabilize this conformer by 0.72 kcal/mol. .
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