WHOI Technical Reports

Permanent URI for this collection

https://hdl.handle.net/1912/554

The Woods Hole Oceanographic Institution publishes technical reports describing projects carried out by WHOI researchers. New reports are added as they become available.

Pre-1978 reports are scanned and added by request; contact the WHOAS project manager whoas@whoi.edu to have a Technical Report added.

Browse

Browsing WHOI Technical Reports by Subject "Acoustic imaging"
  • Technical Report
    Application of acoustic-doppler current profiler and expendable bathythermograph measurements to the study of the velocity structure and transport of the Gulf Stream
    (Woods Hole Oceanographic Institution, 1988-09) Joyce, Terrence M. ; Dunworth, Jane A. ; Schubert, David M. ; Stalcup, Marvel C. ; Barbour, R. Lorraine
    We have addressed the degree to which Acoustic-Doppler Current Profiler (ADCP) and expendable bathythermograph (XBT) data can provide quantitative measurements of the velocity structure and transport of the Gulf Stream. An algorithm has been used to generate salinity from temperature and depth using an historical Temperature/Salinity relation for the NW Atlantic . Results have been simulated using CTD data and comparing real and pseudo salinity files. Errors are typically less than 2 dynamic cm for the upper 800 rn out of a total signal of 80 cm (across the Gulf Stream). When combined with ADCP data for a near-surface reference velocity, transport errors in isopycnal layers are less than about 1 Sv (106 rn3 /s), as is the difference in total transport for the upper 800 rn between real and pseudo data . The method is capable of measuring the real variability of the Gulf Stream, and when combined with altimeter data, can provide estimates of the geoid slope with oceanic errors of a few parts in 108 over horizontal scales of 500 krn .
  • Technical Report
    Description and evaluation of the Acoustic Profiling of Ocean Currents (APOC) System used on R.V. Oceanus cruise 96 on May 11-22, 1981
    (Woods Hole Oceanographic Institution, 1982-11) Joyce, Terrence M. ; Rintoul, Stephen R. ; Barbour, R. Lorraine
    The underway current profiling system used in this study consists of a microprocessor-controlled data logger that collects and formats data from a four-beam Ametek-Straza 300 kHz acoustic Doppler current profiler, heading from the ship's gyrocompass, and navigation information from a Loran-C receiver and a satellite navigation unit. Data are recorded on magnetic tape and some real time calculations are made. The system was first used on a May, 1981 cruise aboard the R.V. OCEANUS in the western North Atlantic. Horizontal currents were profiled to depths of 100m. Time averaging is required to remove effects of ship motion. Errors in our ability to profile ocean currents are estimated to be 5-10 em s-1 for a ten-minute vector average. An intercomparison is made with a moored vector measuring current meter (VMCM). The mean difference in hourly-averaged APOC and VMCM currents over the four-hour intercomparison is a few mm s-1. Data from a variety of oceanic regimes are presented and discussed: these regimes include two Gulf Stream crossings, a warm core ring survey, and shallow water in a frontal zone to the east of Nantucket Shoals.