Field Update: Nov. 23, 2010

The oceanographers from NIWA and WHOI arrived late in the afternoon yesterday and got right to work sorting out their instruments and getting ready to deploy them through the ice shelf. One of the first things to do was to set up the WHOI tripod and winch system that would be used to lower and support the line for the grounding wire for the oceanographic mooring.

When we first started planning the deployment of these oceanographic sensors through the ice shelf we were worried about the risk of hanging sensors in the water below the ice that could only record their data locally. If we had problems picking up the instruments after a few months, either due to the challenges of re-melting the hole, or to problems that could occur when we pulled them up out of the water and through the ice hole, then we could potentially lose all of this valuable (and costly) data. Therefore, we decided to deploy an inductive mooring, which would allow the instruments to not only record their data locally but also transmit their data up the cable to the surface of the ice, and ideally off continent through a satellite link. To accomplish this, we need to deploy a ground wire to complete the circuit, meaning we need to melt a separate hole in addition to the one for deploying the main mooring with its string of instruments. The tripod and winch are part of a system for deploying ice-tethered profilers in the Arctic Ocean. We are using them for the first time to deploy instruments through an ice shelf.

The winch and cable spools are modular and light, so they are easy to use.

Will Ostrom and Craig Stewart set about rigging up the tripod over the small diameter hole for the grounding wire, with the help of Dick Limeburner.

Graham Roberts pitches in to help secure the installation and prepare for the deployment of the full mooring and instruments through the ice tomorrow.

Keep up to date on all of the mooring results at the Mooring Deployment website.

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