Location of the inverted echo sounders.
In September 2004 NOAA initiated a program to monitor the flow of the DWBC in near-real-time. This new program uses moored inverted echo sounders, some of which are additionally equipped with bottom pressure gauges and deep current meters. Data from these instruments is acoustically downloaded by a passing research vessel about every six months without actually recovering the instruments.
The data is then brought back to the lab where it is processed. A preliminary comparison completed using data obtained during 1995-1997 has shown that this combination of instruments can reproduce the transport of a more traditional picket-fence of current meter moorings to within the accuracy of the current meter array (Meinen et al., 2004).
For those unfamiliar with inverted echo sounders, here are a few basic facts about these systems:
One of the inverted echo sounders moored east of Abaco Island (Bahamas) before its deployment aboard the NOAA Ship Ronald H. Brown.