Laboratory and field measurements with a broad band ADCP

A 1200 kHz Broad Band Acoustic Doppler Current Profiler (BBADCP) from RD Instruments was tested in 1992 to determine its applicability to National Ocean Service programs. A series of tow carriage tests was performed at the David Taylor Research Center and comparisons made with standard narrow band ADCP systems. Field tests were performed in the Patuxent River towing the BBADCP in a modified catamaran. The intent is to use the system to perform high resolution current transects from ships of opportunity in coastal waters and estuaries. These tests determined the maximum water track range and tested bottom tracking to depths of 40 meters. Comparisons were performed with a bottom-mounted 1200 kHz narrow band ADCP by anchoring the catamaran 50 meters down river from the platform. The results showed disturbing differences that cannot be adequately explained. Data are presented showing the results of laboratory and field tests and plans are discussed for future tests