HR: 15:25h
AN: OS32C-08    [PDF]
TI: Seismic Reflection Imaging of the Boundary between Norwegian Atlantic Current and Norwegian Sea Deep Water
AU: * Nandi, P
EM: pnandi@uwyo.edu
AF: Department of Geology and Geophysics, University of Wyoming, P.O. Box 3006, Laramie, WY 82071 United States
AU: Holbrook, W S
EM: steveh@uwyo.edu
AF: Department of Geology and Geophysics, University of Wyoming, P.O. Box 3006, Laramie, WY 82071 United States
AU: Pearse, S
EM: pearse@uwyo.edu
AF: Department of Geology and Geophysics, University of Wyoming, P.O. Box 3006, Laramie, WY 82071 United States
AU: Paramo, P
EM: paramo@uwyo.edu
AF: Department of Geology and Geophysics, University of Wyoming, P.O. Box 3006, Laramie, WY 82071 United States
AB: Water-column reflections acquired on a seismic survey in the Norwegian Sea and corroborated by an XBT survey suggest that traditional multi-channel seismic methods can distinguish boundaries between major water masses. The study area traverses the boundary between the Norwegian Atlantic Current (NwAC) and the adjacent, and underlying, Norwegian Sea Deep Water (NSDW). Stacked seismic reflection profiles clearly delineate an upper acoustically transparent surface layer separated from a lower transparent water mass by a highly reflective boundary layer. We interpret the upper water mass to be the NwAC and the lower water mass to be NSDW. Depth to the bottom of the upper layer and thickness of the boundary layer correspond to the published depth of the NwAC and thickness of a layer of rapidly varying temperature separating it from the NSDW. Reflections seen in the seismic data result from abrupt, but subtle, changes in sound speed caused by change in temperature on the order of $0.1\deg$C in the boundary layer. These results suggest that the boundaries between major water masses can be seismically imaged if they contain fine-scale thermohaline structure.
DE: 4500 OCEANOGRAPHY: PHYSICAL
SC: Ocean Sciences [OS]
MN: 2003 Fall Meeting