APPLICATION: ADCPs Measure Deep Water Abyssal Storm

Click image to enlarge. A subset of the entire dive (lower panel) shows a 65 cm/s current pulse in this data. Data courtesy of Ian MacDonald and William Bryant of Texas A&M University.

Texas A&M's researchers Ian MacDonald and William Bryant have just completed the first phase of a bottom boundary layer study in 2200m of water in the Gulf of Mexico. They used the Alvin submersible, owned by Woods Hole Oceanographic Institute, which was equipped with a deepwater 300kHz ADCP to measure 60-90 meters of currents next to the ocean floor.

The study was conducted to investigate the potential relationship between recently discovered 'furrows' in the ocean floor and ocean currents. One theory postulates more intense tidal currents due to interactions at the base of the continental slope. Higher velocities there, called an abyssal storm, may have excavated the furrows that are up to 100 feet wide, 30 feet deep and tens of miles long. Conventional wisdom says there should be little current at the base of the ocean. But researchers MacDonald and Bryant's results showed currents of up to 65cm/sec.

The research was conducted as a preliminary study for oil exploration research. MacDonald was quoted recently as saying, "[Oil] Platform design has always had to withstand hurricane-force winds and waves, but the undersea storms strong enough to carve these furrows would present a new level of hazard." Additional research projects are planned to better understand these phenomenon in the Gulf region. Read more about this study on Texas A&M's website: http://rev.tamu.edu/stories/00/101100-6.html.