Journal of Oceanography

, Volume 63, Issue 6, pp 995–1007 | Cite as

Correction method for full-depth current velocity with lowered acoustic Doppler current profiler (LADCP)

  • Kanae Komaki
  • Masaki Kawabe
Original Articles


A new method is presented to process and correct full-depth current velocity data obtained from a lowered acoustic Doppler current profiler (LADCP). The analysis shows that, except near the surface, the echo intensity of a reflected sound pulse is closely correlated with the magnitude of the difference in vertical shear of velocity between downcast and upcast, indicating an error in velocity shear. The present method features the use of echo intensity for the correction of velocity shear. The correction values are determined as to fit LADCP velocity to shipboard ADCP (SADCP) and LADCP bottom-tracked velocities. The method is as follows. Initially, a profile of velocity relative to the sea surface is obtained by integrating vertical shears of velocity after low-quality data are rejected. Second, the relative velocity is fitted to the velocity at 100–800 dbar measured by SADCP to obtain an “absolute” velocity profile. Third, the velocity shear is corrected using the relationship between the errors in velocity shears and echo intensity, in order to adjust the velocity at sea bottom to the bottom-tracked velocity measured by LADCP. Finally, the velocity profile is obtained from the SADCP-fitted velocity at depths less than 800 dbar and the corrected velocity shear at depths greater than 800 dbar. This method is valid for a full-depth LADCP cast throughout which the echo intensity is relatively high (greater than 75 dB in the present analysis). Although the processed velocity may include errors of 1–2 cm s−1, this method produced qualitatively good current structures in the Northeast Pacific Basin that were consistent with the deep current structures inferred from silicate distribution, and the averaged velocities were significantly different from those calculated by the Visbeck (2002) method.


Correction method LADCP current velocity echo intensity North Pacific 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Cunningham, S. A., M. J. Griffiths and B. A. King (1997): Comparison of bottom-tracking and profiling LADCP data in a section across the ACC at Drake Passage. International WOCE Newsletter, 26, 39–40.Google Scholar
  2. Egbert, G. D., A. F. Bennett and M. G. G. Foreman (1994): TOPEX/Poseidon tides estimated using a global inverse model. J. Geophys. Res., 99, 24,821–24,852.Google Scholar
  3. Firing, E. (1998): Lowered ADCP development and use in WOCE. International WOCE Newsletter, 30, 10–14.Google Scholar
  4. Firing, E. and R. L. Gordon (1990): Deep ocean acoustic Doppler current profiling. Proc. IEEE Fourth Working Conf. on Current Measurements, Clinton, MD, Current Measurement Technology Committee of the Oceanic Engineering Society, 192–201.Google Scholar
  5. Firing, E., S. Wijffels and P. Hacker (1998): Equatorial subthermocline currents across the Pacific. J. Geophys. Res., 103, 21,413–21,423.Google Scholar
  6. Fischer, J. and M. Visbeck (1993): Deep velocity profiling with self-contained ADCPs. J. Atmos. Oceanic Technol., 10, 764–774.CrossRefGoogle Scholar
  7. Hall, M. M., T. M. Joyce, R. S. Pickart, W. M. Smethie, Jr. and D. J. Torres (2004): Zonal circulation across 52°W in the North Atlantic. J. Geophys. Res., 109, C110088, doi:10.1029/2004JC002384.Google Scholar
  8. Johnson, G. C. and J. M. Toole (1993): Flow of deep and bottom waters in the Pacific at 10°N. Deep-Sea Res. I, 40, 371–394.CrossRefGoogle Scholar
  9. Johnson, H. P., S. L. Hautala, T. A. Bjorklund and M. R. Zarnetske (2006): Quantifying the North Pacific silica plume. Geochemistry Geophysics Geosystems, 7, Q05011, electronic journal (
  10. Kawabe, M., S. Fujio and D. Yanagimoto (2003): Deep-water circulation at low latitudes in the western North Pacific. Deep-Sea Res. I, 50, 631–656.CrossRefGoogle Scholar
  11. Kawabe, M., D. Yanagimoto, S. Kitagawa and Y. Kuroda (2005): Variations of the deep western boundary current in Wake Island Passage. Deep-Sea Res. I, 52, 1121–1137.CrossRefGoogle Scholar
  12. Mantyla, A. W. and J. L. Reid (1983): Abyssal characteristics of the World Ocean waters. Deep-Sea Res., 20, 871–885.Google Scholar
  13. RD Instruments (1996): Principles of Operation, A Practical Primer.Google Scholar
  14. Roden, G. I. (2000): Flow and water property structures between the Bering Sea and Fiji in the summer of 1993. J. Geophys. Res., 105, 28,595–28,612.Google Scholar
  15. Visbeck, M. (2002): Deep velocity profiling using lowered acoustic Doppler current profilers: Bottom track and inverse solutions. J. Atmos. Oceanic Technol., 19, 794–807.CrossRefGoogle Scholar
  16. Wijffels, S., M. Hall, T. Joyce, D. J. Torres, P. Hacker and E. Firing (1998): Multiple deep gyres of the western North Pacific: A WOCE section along 149°E. J. Geophys. Res., 103, 12,985–13,009.Google Scholar

Copyright information

© The Oceanographic Society of Japan/TERRAPUB/Springer 2007

Authors and Affiliations

  1. 1.Ocean Research InstituteThe University of TokyoMinamidai, Nakano-ku, TokyoJapan
  2. 2.Ocean Policy Research Foundation, 1-15-16Toranomon, Minato-ku, TokyoJapan

Personalised recommendations