Slocum underwater gliders 'fly' through the water in a vertical saw-toothed pattern, sampling the water for a suite of variables including temperature and salinity.  Gliders move through the water by adjusting their density with a pump system and steering with a tail rudder.

Gliders navigate by following a set of waypoints that are uploaded before a mission. During a mission, the glider surfaces at each waypoint and uses GPS to check it's location. New waypoints can be added during a mission by uploading them remotely.

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Gliders are versatile and easily modified for each mission.  Our gliders at UCSC have a CTD (conductivity-temperature-depth) sensor, an oxygen optode, and an ADCP (acoustic doppler current profiler). They can also measure chlorophyll, backscatter, and CDOM (colored dissolved organic material).

Gliders are easily deployed and recovered by hand off of a small boat. Once deployed, a glider completes several "test drives", before navigating to it's first waypoint and beginning a sampling mission.

Gliders are very energy efficient and can continuously sample the upper ocean for weeks at a time.  High resolution data from gliders allows scientists to produce detailed maps of the ocean to study physical and biological processes.  Image below:  A sub-surface chlorophyll maximum (red band) identified by a glider.