Slocum Gliders as Mobile Listeners

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As part of Gliderpalooza 2013, the Ocean Tracking Network outfitted Slocum autonomous underwater vehicles (gliders) with Vemco mobile transceivers. The focus of Gliderpalooza was to test our capability as disparate research groups to deploy our gliders in concert to try and capture conditions during interesting weather events.

vmt_slocum_lab

A Vemco Mobile Transceiver mounted to the tail of a Slocum glider.

OTN was able to deliver the externally-mounted VMTs to most researchers ahead of their deployments, and were able to collect detection data from these units after the fact.

As partners in Gliderpalooza, we also were given a full copy of each glider’s raw data, which included their GPS locations, collected on their infrequent surfacings (every 6 or so hours). We also obtained a copy of all the oceanographic data each glider was recording, ocean physics, chemistry, and biological markers were all shared between the many organizations that participated in Gliderpalooza.

As a data source, these AUVs are interesting, but not entirely unique. OTN has been using autonomous underwater assets in the form of grey seals for some time. While we have much better success in steering these AUVs, the data stream is very similar, amounting to a series of GPS hits over time, as well as a series of detections over time. In both cases, from the GPS data, we match the detection time with a pair of GPS locations registered on surfacings before and after to provide an interpolated position for each detection event. While the nature of each detection is not yet publishable, the locations of each detection are. And so, the detection results for Gliderpalooza 2013 look like this:

gliderpalooza_detections

Detections by Slocum Gliders during Gliderpalooza 2013

While these are not as many detections as one might get from a receiver line over the course of a whole season, the pairing of real-time ocean conditions measured by the glider platform around each detection provides a wealth of contextual information.

Gliderpalooza 2014 is beginning this August. There are plans for 19 or more gliders deployed from Newfoundland to Georgia, and we are all expecting this hurricane season to be more eventful than the last. OTN intends to have its mobile transceivers listening for tagged animals on every glider to record more of this valuable intersection between marine biology and oceanography.

 

Story by Jonathan Pye, OTN Headquarters

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