ITP18 Deployment Operations

In order for the last day of ice operations to be successful, a better-than-average ice floe was needed to act as the platform for a buoy cluster consisting of an AOFB, IMB, and ITP 18. Fortunately, the ice in the northeast Beaufort Sea contained more patches of remnant multiyear ice patches compared to the thin ice encountered previously to the west. After searching in the helicopter for only half an hour, an outstanding ice floe was spotted and when drilled showed a relatively uniform thickness around 3 m. The site was so close to the ship, that only an hour later, the first personnel and gear were delivered for the deployment. Another hour, and all 16 personnel (including rifle bearer, photographers, and other ice surveyors besides the buoy deployment team) and gear were delivered to the ice and the AOFB sensor head was being lowered through the 10.5 inch hole into the seawater. Meanwhile, the IMB was being installed 20 m away. Half an hour later, the AOFB surface buoy was deployed and the ITP deployment started near the IMB while the AOFB ice thermistor string was installed and operation of the buoy and wind generator were verified. Two hours were consumed by the ITP deployment, and then all personnel and gear were returned to the ship exactly 7 hours after the first deployment flight from the ship. Good weather contributed to the efficiency of the field work.

More information and photos on the deployment operation are also available at: https://www.whoi.edu/page.do?pid=67521.

The thin ice conditions and light fog on the morning of the final ITP deployment.

The thin ice conditions and light fog on the morning of the final ITP (and ice based observatory) deployment of the JOIS 2012 cruise were somewhat of a concern at the beginning of the ice reconnaissance. (Photo by Rick Krishfield)

During the ice survey, Chris Swannell and Steve Manganini drill a 2 inch diameter test hole to measure the ice thickness. Relatively nearby the ship, a decent 3 m thick, relatively uniform, multiyear floe was found mixed in with the thinner ice occupying most of the area. The floe had some ponding, but also a rather large flat expanse for deploying the three ice-mounted autonomous buoy systems. (Photo by Rick Krishfield)

First the AOFB was installed and capped with the surface electronics buoy by Kris Newhall and Jim Dunn while a slip line is used with the tripod to lower the sensor package under control. (Photo by unknown)

Mike Dempsey reads data on a keypad connected to the unit to verify that the sensors are all functioning properly.

Meanwhile, having completed installation of the IMB, Mike Dempsey reads data on a keypad connected to the unit to verify that the sensors are all functioning properly. (Photo by Luc Rainville)

Another 10 inch diameter hole is augured for the ITP deployment using a chainfall to take up the weight of the auger head when the blade is bogged down by the liquid and porous ice at the bottom boundary. (Photo by Rick Krishfield)

ITP 18 profiler suspended on the wire for pre-deployment testing in the sunny afternoon. (Photo by Rick Krishfield)

AOFB with wind generator for enhanced sampling rate from the helicopter passenger seat. (Photo by Luc Rainville)

Diagram of distances between AOFB, other buoys and nearest ridges and melt ponds. (Photo by Rick Krishfield)

The buoys are only specs on the outstanding floe as seen from the helicopter on the last flight back to the ship. (Photo by Rick Krishfield)