A NEAR-SURFACE MICROSTRUCTURE SENSOR SYSTEM USED DURING TOGA COARE - PART I - BOW MEASUREMENTS

High-resolution probes mounted on the bow of the vessel at a 1.7-m dep th in an undisturbed region ahead of the moving vessel were used for m icrostructure and turbulence measurements in the near-surface layer of the ocean during TOGA COARE. The probes measured temperature, conduct ivity, pressure, three-component fluctuation velocity, and two compone nts of acceleration. Accumulation of large amounts of high-quality nea rsurface data poses a difficult challenge, and deployment from the bow of a ship, such as is done with these sensors, requires rugged, well- calibrated, and low-noise sensors. The heaving motion of the ship that causes the sensors to break through the surface requires data process ing algorithms unique to this application. Due to the presence of surf ace waves and the associated pitching of the vessel, the bow probes '' scanned'' the near-surface layer of the ocean. Combining the bow senso r's signals with the ship's thermosalinograph pumping water from 3-m d epth resulted in the near-surface dataset with both fine remporal/spat ial resolution and high absolute accuracy. Contour plots calculated us ing the bow signals reveal the spatial structure of the diurnal thermo cline and rain-formed halocline. The localization in narrow frequency bands of the vibrations of the bow sensors allows calculation of dissi pation rates. The characteristics of the sensors and the data processi ng algorithms related to the periodic surface penetration by the senso rs are discussed in this paper.