Monitoring and Event Response Moorings

RAFOS floats deployed in the neutrally buoyant plumes (largest total heat input), as well as in Event plumes (largest short term heat input), increase our understanding how these plumes become incorporated into the regional circulation.

In 1996 an eruption detected by SOSUS occurred on the Northern Gorda Ridge. An early response cruise found a large event plume in March, and a second cruise found a different event plume in April. This event plume became the first to be seeded and tracked with a neutrally buoyant RAFOS drifter. The RAFOS drifter tracked the eddy-like rotation of event plumes and allowed us, for the first time, to resample the same plume 2 months later. Little chemical change was found between sampling periods, suggesting that event plumes have a long residence time as discrete entities in the deep ocean. The Gorda Ridge event was unusual in another way, in that venting was extinguished within 3 months of the eruption, much faster than at either Cleft or CoAxial. (Click image for larger view.)

View animation of RAFOS float trajectory and plume model:
Quicktime player .mov (.2 Mb) | FLC player .fli (.2 Mb)

Player downloads:
fli: http://woodshole.er.usgs.gov/operations/modeling/flc.html
mov/mpeg: http://www.apple.com/quicktime/download/

Physical Oceanography Methods: Current Meters | CTD | RAFOS