Documentation for University of Washington Seaglider records archived at NODC (NODC Accession 0092291)

Seagliders are small (1.8m hull), reusable, long-range, and buoyancy-driven autonomous underwater vehicles (AUVs) designed to glide from the ocean surface to as deep as 1-km depth and back while collecting profiles of temperature, conductivity (hence salinity), dissolved oxygen, chlorophyll fluorescence, and optical backscatter at varying vertical resolutions.
Seagliders collect measurements along saw-tooth paths with a slope of 1:1-3.5 through the ocean at speeds through the water of about 20 cm/s. They are commanded remotely and report their data in near-real time via Iridium satellite data telemetry. They use GPS navigation at sea surface to dead reckon underwater toward commanded targets.
Differences between dead-reckoned and actual displacements permit estimation of the depth-averaged horizontal velocity. Estimates of geostropic or cyclostrophic shear can be integrated vertically and referenced to the depth-averaged current to obtain sections of absolute geostrophic current with typical errors of the order of 0.01 m/s. The difference between observed and expected descent rate gives a profile of vertical velocity, showing internal wave and turbulent deep mixing activity.