Field Update: Nov. 16, 2010

The weather has cleared again, so the helicopter flight to bring the UNAVCO folks back to McMurdo is on the schedule. Joe and Lisa are gathering their belongings and getting ready to leave camp. The Pisten Bully is waiting on a new hose to fix the leak discovered yesterday, and we’re moving the outhouse to a new location this morning, which is the subject of keen interest by everyone in the camp. A group has gathered to assist with the move and ensure proper alignment between the seat and the ice hole.

We first prepare the site, and then Tristan uses the MTL (multi-terrain loader) to move the outhouse (or “dunnie”, as they say in NZ) into position. Everyone pitches in to help with the final installation, placing a strap over the roof to hold the outhouse in place in case the wind picks up, drilling additional holes as required using a jiffy drill attached to a few “flights” to ream out the hole, and conducting maintenance work like chipping away the ice that had accumulated inside the structure during its previous period of winter storage, which required an ice axe and plenty of muscle to dislodge. After all of this activity is completed, the daily work begins again, and it’s left to Joe and Lisa to wait for the arrival of the helicopter from McMurdo.

Joe has already checked that the GPS units are recording data and has made a preliminary calculation to determine that the ice shelf is moving at about 2 meters per day laterally, which confirms our previous estimates. As more data is collected we’ll learn if the motion is continuous and at the same rate each day or if it varies from day to day and by how much. We’ll also look at the vertical motion at each site and between sites to learn more about how the ice shelf responds to tidal currents throughout the tidal cycle. We expect to learn a lot over the coming months about these motions and hope to integrate this knowledge with what we learn about the ocean under the ice shelf from the current meters and other oceanographic instruments that we will be deploying through the ice shelf in a few short days.

Tamsin Falconer is in communication with the helicopter pilot as they approach the camp and prepare to land. We’ve prepared a landing site with orange markers (orange bags filled with snow to weigh them down) and have reviewed the protocols for approaching a helicopter after it lands – wait in clear sight of the pilot for a signal to approach, approach from the front away from the rotors, carry cargo below your waist, and be cautious.

Joe and Lisa board their flight and the helicopter takes off to return to town as we go back to work. A group of three Skuas (Antarctic birds) have joined us for a visit, but they continue on their way after a short rest.

The helicopter has brought a new hose for the Pisten Bully, so JR and Tristan prepare to open the cab so they can have a closer look at the engine and make the needed repairs. The cab of the Pisten Bully is unlatched from the frame and then it is hydraulically lifted up and forward using a manual jack that is pumped up and down. The rear compartment is then lifted up and back to allow access to the engine. It’s a bit of a strange site, seeing the vehicle open up like this, but it gives a good view of the Mercedes-Benz engine of the PB. The repairs are made quickly, the fluids are topped off, and we are ready to get back to surveying and flagging again within a short while, after getting the boom back in place and the ground penetrating radar re-installed in the cab of the vehicle. Claude and I head out of camp with Richard to drive along the gravity and seismic lines and place flags at each waypoint entered into the hand-held GPS units that we used for the survey. The end result is a line of flags stretching off into the distance that will guide the people who come after us to actually conduct these experiments.

It’s been a full day for us, but we know that the team working with the hot water drill have been busy as well, so we look forward to learning about what they’ve accomplished while we were away. It’s time for some food and some rest though, so we head to the galley and then off to bed.

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