4. Sound reflections reveal ocean temperature profiles
Reflection seismology, using an array of air guns and hydrophones towed from a ship, is commonly used to investigate geologic structures below the ocean floor. Recently, this technique has been applied to investigate oceanographic structures. Noting that layers in the ocean are nearly horizontal, and that sound speed profiles through layered media can be readily determined by reflection seismology inversion techniques, Wood et al. hypothesize that these sound speed profiles can be used to constrain ocean temperature profiles. The authors test their method using modeled seismic data and find good agreement. They then apply their method to actual seismic data acquired in the Norwegian Sea, corroborating the results with direct measurements of ocean temperature. They find that even with a seismic acquisition system not specifically designed or calibrated for seismic oceanography, temperature contrasts within the ocean can be recovered to within 1 degree Celsius. Because this method can be used remotely and rapidly, the authors expect that this new technique may prove useful in constraining models of ocean mixing and global heat transfer.
Title: Full waveform inversion of reflection seismic data for ocean temperature profiles
Authors: Warren T. Wood: Naval Research Laboratory, Stennis Space Center, Mississippi, U.S.A.;
W. Steven Holbrook: Department of Geology and Geophysics, University of Wyoming, Laramie, Wyoming, U.S.A.;
Mrinal K. Sen and Paul L. Stoffa: Institute for Geophysics, University of Texas at Austin, Austin, Texas, U.S.A.
Geophysical Research Letters (GRL) paper 10.1029/2007GL032359, 2008; http://dx.doi.org/10.1029/2007GL03235
|Contact: Peter Weiss|
American Geophysical Union