ITP Deployment: Getting an instrument through Arctic ice

The ITP system is designed so that it may be deployed directly from an icebreaker using man hauling or helicopter ferrying of the equipment to the deployment site, or installed up to 300 hundred miles from fuel depots with a single flight of a small aircraft.

Together with the tether end weight, the ITP hardware totals approximately 450 kg (1000 lb). Field technicians, emergency survival gear, and the minimum deployment equipment bring the helicopter payload up to 1000 kg (2200 lb). This weight may be transported up to a maximum 280 miles round trip by a medium lift helicopter (such as the Bell 212), or over 600 miles round trip by the DeHavilland Twin Otter airplane. For shorter round trip distances, several ITP systems could be loaded onto and deployed from a single Twin Otter.

The deployment operations for the first ITPs were supported by the Canadian Coast Guard icebreaker Louis S. St-Laurent utilizing BO-105-CB helicopters for reconnaissance to select an appropriate icefloe, and to transport gear and people for the deployment. These particular helicopters can carry up to 4 passengers and have a stated payload (fuel and cargo) of approximately 675 kg (1500 lb), so several flights were needed to transport a single ITP system, deployment apparatus, and personnel.

Reconnaissance flights to select the icefloe typically include 1-2 scientists (in addition to the pilot and a rifle bearer).   Multiyear icefloes are identified, landed upon and drilled (using a 2” hand auger) to determine ice thickness. The ideal floe for an ITP deployment is multi-year ice (which can be identified by the lighter shade of blue color in melt ponds in summer) that is relatively thick (2.5 to 4.5 m), level, and sparsely ponded.  Thick floes are thought better able to survive for long time and less prone to rafting.

ITP systems are transported to their deployment sites in several pieces: surface package, wire tether on aluminum spool, tether end weight, and the Profiler unit.

A motorized auger is used to create an 11"- diameter hole through the icefloe. 

With the aid of a light-weight, portable tripod, the tether ballast weight and subsurface tether is deployed through the hole.

At a convenient point, the ITP is mounted on the wire (two bracket connections plus the inductive modem bracket) and eased down the wire through the ice hole.

After making one mechanical and one electrical connection at the surface unit, the package is positioned onto a wooden palette over the hole and the tripod is disassembled. A portable computer is connected temporarily to the surface controller to verify instrument functionality before the technicians depart the site.  Based on the preprogrammed sampling plan entered in the ITP profiler, the instrument will then start working.

Once an ice floe has been identified and all of the gear has been positioned at the site, the ITP deployment operation typically takes  between 2-4 hours to complete.  From first landing on an appropriate icefloe to last departure, a complete ITP system can be deployed in 4-8 hours.