Fine- and Microstructure Characteristics Near an Upper Ocean Front

摘要

A set of observations were collected in the Frontal Air-Sea Interaction Experiment (FASINEX) to examine the mechanisms responsible for mixing near an upper ocean front. One potential mechanism is Kelvin Helmholtz type shear instability associated with the near-inertial wave field. The FASINEX area was viewed as excellent site to examine this mechanism since previous studies suggested that fronts can radiate inertial waves and that low frequency internal waves can be trapped in the vorticity field of a frontal jet. Observations were collected from the R/V Endeavor during the one-month long intensive phase of FASINEX in Feb/Mar 1986. The experiment was located at the sub-tropical convergence front in the Sargasso Sea. Large-scale surveys of the temperature, salinity and density fields at the front were obtained with a wire lowered CTD. Fine-scale temperature, salinity and velocity information and microscale temperature, conductivity and velocity data were collected by a newly developed free-fall profiler. A series of 40 deployments of the profiler were made, each sampled the upper 1000 m of the water column. We discuss some average properties of the fine-scale velocity and density fields, Richardson number statistics and dissipation rates observed in FASINEX. Reprints. (EDC)