Shipboard Acoustic Doppler Current Profiling

on RVIB Nathaniel B. Palmer and RVIB Laurence M. Gould

The US National Science Foundation (NSF) Office of Polar Programs (OPP) funds the operation of two Research Vessel Ice Breakers (RVIB) in the Antarctic: the Nathaniel B. Palmer and the Laurence M. Gould. Both ships have two shipboard ADCPs, an RD Instruments narrowband VM-150 profiler, and an Ocean Surveyor (phased array) 38 KHz profiler. The ADCP system is made up of these two instruments along with GPS navigation and with heading corrections provided by Seapath or Ashtech ADU-2 GPS attitude sensors. These systems offer the prospect of routine high-resolution current profile measurements in the top 300 m and lower resolution profiling as deep as 1200m, along a variety of cruise tracks through otherwise rarely sampled waters of the Southern Ocean.

Dr. Teresa Chereskin at Scripps Institution of Oceanography and Eric Firing at University of Hawaii are funded by the NSF OPP to oversee the operation of these ADCP systems.

At sea, data from the ADCPs and ancillary sensors are logged by a computer running a data acquisition system developed originally for this project at University of Hawaii. The data streams include roughly one-second gyro heading, Ashtech (or Seapath) heading, gps position, speed of sound in the NB150 transducer well, and single-ping adcp data from each instrument. The computer averages the single-ping data into 5-minute averages and processes these averaged data creating a regularly updated, preprocessed and edited dataset. Once a day, it emails us a report with system information, data quality parameters, and a sample of recent data. Figures are generated at University of Hawaii upon reciept of the email. Throughout the day, the data acquisition system updates figures on a ship's website. (This example is from the Gould, heading north over the Patagonia shelf). The onboard website is accessible to anyone on the ship's network, and contains links to recently generated figures, the data used to create them, and adcp logging system documentation. Access to the data is also provided through shared disks on the ship's network.

As part of this project, summary plots for N.B.Palmer cruises are available, along with access to the data in netcdf format, and to predicted barotropic tides along the cruise tracks, also in netcdf.

The data collected on the L.M.Gould are handled similarly, with an additional daily report.

Processed data are archived by the NODC JASADCP.

Status of the project and more plots of the resulting measurements will be added to this page.

We thank the US National Science foundation for supporting the University of Hawaii component of this project through grants OPP-9816483, OPP-0337375, and OPP-0838714.