A. Soloviev et al., A near-surface microstructure sensor system used during TOGA COARE. Part II: Turbulence measurements, J ATMOSP OC, 16(11), 1999, pp. 1598-1618
New techniques developed for near-surface turbulence measurements during th
e Tropical Ocean Global Atmosphere (TOGA) Coupled Ocean-Atmosphere Response
Experiment (COARE) employ a difference in spatial scales of turbulence and
surface waves. According to this approach, high relative speed of the meas
urements provides separation of the turbulence and surface wave signals. Du
ring the TOGA COARE field studies, high-resolution probes of pressure, temp
erature, conductivity, fluctuation velocity, and acceleration were mounted
on the bow of the Vessel at a 1.7-m depth in an undisturbed region ahead of
the moving vessel. The localization in narrow frequency bands of the vibra
tions of the bow sensors allows accurate calculation of the dissipation rat
e. A coherent noise reduction algorithm effectively removes vibration conta
mination of the velocity dataset. Due to the presence of surface waves and
the associated pitching of the vessel, the bow probes "scanned" the near-su
rface layer of the ocean. Contour plots calculated using the bow signals pr
ovide a spatial context for the analysis of near-surface turbulence. A fast
-moving free-rising profiler equipped by similar probes sampled the near-su
rface turbulence during stations. Theory of the three-component electromagn
etic velocity sensor and examples of data obtained by bow sensors and free-
rising profiler are also presented in this paper.