Application of collected data
Presentations at the DBCP Technical Workshop
Buenos Aires, Argentina, 17-18 October 2005

Theme 1: Applications of buoy data

5. A New Device to Measure Internal Waves in the Upper Ocean 

Author: Carter Ohlmann (Scripps Institution of Oceanography)

Abstract: New drifter technology utilizing GPS and terrestrial cellular communications allows inexpensive collection of high-resolution trajectories in the near-shore region to address questions related to small-scale advection and dispersion. The drifter uses GPS to determine its position, and the Mobitex terrestrial cellular communications system to transmit the position data in near-real-time. This configuration allows position data with order meter accuracy to be sampled every few minutes, and transmitted inexpensively. Near-real-time transmission of highly accurate position data enables the drifters to be easily retrieved and redeployed. Near 300 drifter tracks collected off the Santa Barbara and San Diego coasts show validations of high frequency (HF) radar observations of near-surface currents improve by roughly 50% when comparisons are made with average values computed from more than 15 drifter observations collected on time and space scales commensurate with HF radar observations. The improvement is due to drifter resolution of sub-grid-scale eddies that are included in time-space averaged HF radar fields. The drifters resolve scales of motion not present in HF radar surface current maps, and are thus complementary in coastal ocean observing systems.