Near-inertial and thermal upper ocean response to atmospheric forcing in the North Atlantic Ocean
Silverthorne, Katherine E.
MetadataShow full item record
LocationNorth Atlantic Ocean
Observational and modeling techniques are employed to investigate the thermal and inertial upper ocean response to wind and buoyancy forcing in the North Atlantic Ocean. First, the seasonal kinetic energy variability of near-inertial motions observed with a moored profiler is described. Observed wintertime enhancement and surface intensification of near-inertial kinetic energy support previous work suggesting that near-inertial motions are predominantly driven by surface forcing. The wind energy input into surface ocean near-inertial motions is estimated using the Price-Weller- Pinkel (PWP) one-dimensional mixed layer model. A localized depth-integrated model consisting of a wind forcing term and a dissipation parameterization is developed and shown to have skill capturing the seasonal cycle and order of magnitude of the near-inertial kinetic energy. Focusing in on wintertime storm passage, velocity and density records from drifting profiling floats (EM-APEX) and a meteorological spar buoy/tethered profiler system (ASIS/FILIS) deployed in the Gulf Stream in February 2007 as part of the CLIvar MOde water Dynamics Experiment (CLIMODE) were analyzed. Despite large surface heat loss during cold air outbreaks and the drifting nature of the instruments, changes in the upper ocean heat content were found in a mixed layer heat balance to be controlled primarily by the relative advection of temperature associated with the strong vertical shear of the Gulf Stream. Velocity records from the Gulf Stream exhibited energetic near-inertial oscillations with frequency that was shifted below the local resting inertial frequency. This depression of frequency was linked to the presence of the negative vorticity of the background horizontal current shear, implying the potential for near-inertial wave trapping in the Gulf Stream region through the mechanism described by Kunze and Sanford (1984). Three-dimensional PWP model simulations show evidence of near-inertial wave trapping in the Gulf Stream jet, and are used to quantify the resulting mixing and the effect on the stratification in the Eighteen Degree Water formation region.
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2010
Showing items related by title, author, creator and subject.
Macdonald, Alison M. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1995-08)Data from fifteen globally distributed, modern, high resolution, hydrographic oceanic transects are combined in an inverse calculation using large scale box models. The models provide estimates of the global meridional ...
Moffat Varas, Carlos F. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2007-09)Observations of current velocity, temperature, salinity and pressure from a 2-year moored array deployment and four hydrographic cruises conducted by the United States Southern Ocean GLOBEC program on the western Antarctic ...
Cosmogenic ³²P and ³³P in the atmosphere and aligotrophic ocean and applications to the study of phosphorus cycling Waser, Nathalie A. D. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1992-11)Cosmogeruc P-32 (14.28 days) and P-33 (25.3 days) are powerful tracers of upper ocean P cycling, when coupled with time-series of the atmospheric sources. A method was developed to determine the low-level beta activities ...