Posts Tagged ‘seismometer’

Pine Island Glacier 2011: The Story Continued

January 17th, 2012 by Maria-Jose Viñas

By Bob Bindschadler

One of the GPS receivers and seismometers installed on Pine Island Glacier's ice shelf to monitor to monitor its flexing and cracking.

McMurdo (Antarctica), 14 January — Delayed flights seem to be the rule this season. Our flight to Christchurch was cancelled late Thursday night because of expected bad weather here. On the next try, there was a mechanical problem that required a part that had to be shipped to Christchurch, so I’m still in McMurdo. The next attempt by the C-17 will be to fly to Antarctica on late Sunday. If successful, we will board it in the early morning hours of Monday and we’ll be smelling the lush summer greenness of New Zealand five hours later.

Let me return to the saga at PIG Main Camp. I left the tale at the point that I was being told on Friday, 6 January, that if the helicopters had not been flown to PIG by the end of the following day, they would not be delivered this season and my field team would be returned to McMurdo—game over, season ended. I objected—not to the date, nor to the conclusion that there would not be enough time to execute the drilling/ocean profiling part of the field work. What I objected to was calling a halt to other science activities that still could be supported with the helicopters. I pointed out that our second science objective did not require a separate camp on the ice shelf, but could be supported by day trips based entirely from the PIG Main Camp. In this case, four days would not be spent transferring people and equipment to the ice shelf camp, and another four days returning them. These could be spent gathering data from isolated places on the ice shelf only accessible by helo and everyone would be back in Main Camp every night. There were many days still left where important science could (and should) be done. Better yet, by not having a remote camp that could only be pulled off the ice shelf by the helos, the helo schedule for disassembly for return to McMurdo was no longer at risk. But the helos still had to be flown out to PIG to do this work.

“No” was the answer. I was stunned. Something very fundamental had failed to be understood while I was in McMurdo; our science program had many components and when I had presented our prioritization of the individual elements and focused on achieving the most important element (the drilling and ocean measurements), it did not mean that it was “drilling or nothing”. Once the drilling objective could not possibly be met, the next step was to consider how to achieve the next most important objective. Not only could this second priority objective be met (there were still nearly two weeks we could have worked on it), but the risks to the helicopter schedule were much lower. The logic was ironclad, yet no one in McMurdo supported my appeal to still fly out the helos.

“No” remained the answer, and when it came from the National Science Foundation’s on-site head of logistics, there was no point in continuing to stress either the science to be gained or the reduced risk to the helo schedule. Most scientists will bristle when sound logic fails to persuade and so it was with me. This made no sense to me and I was not receiving any suitable explanation over the sat phone. Enthusiasm for this project on the part of the helo operators had noticeably decreased as the schedule delays mounted, but supporting this new science objective reduced their risk. However, I feel they now had what they wanted—a deadline that had passed that reduced their risk to zero and they would not let that go. Science wasn’t going to get done. That was my problem, not theirs. Nor did NSF seem to care enough to order the helos to PIG. ^%$^%#&*!!

I was done, right? Not quite. I’m nothing if not dogged in my determination to get something to show for the extraordinary effort that had led to us being where we were. At the very bottom of our science priority list was the task of setting out five GPS receivers and seismometers on the ice shelf to monitor the flexing and cracking of the ice shelf that we think is driven by the spatial variability of the strong melting of the ice shelf’s underside. Because the Twin Otter had landed already in the area where these instruments could be useful, I pleaded for enough Twin Otter time to put out a minimal set of three of these instruments. I expected three days would be required (they had been willing to provide two days to help set up the drill camp, so I had some hope this would be feasible in their minds). There was silence on the phone, but shortly McMurdo voiced some willingness to consider this request. They would have to see if the impact of this new request could be accommodated, but they were optimistic. Whew, not much, but something!

The next day I was told that we could expect three days of Twin Otter support to put in three GPS/seismic stations; not just any three days, but Monday through Wednesday, but that I should try to accomplish it in two. And it would start…tomorrow. The very next day?! I had to accept. We had to hustle to pull out of our cargo the required pieces (as the lowest priority activity, these pieces were scattered around and well buried in other gear) and pre-fab as much of the instrumentation as possible before the Twin Otter arrived. We worked late into the night and went to bed hoping that the weather improved enough that the Otter would come the next morning.

Morning clouds parted quickly the next day and we heard to expect the Otter to arrive by 10:30 AM. We were (just) ready and had a quick conversation with the pilots about what we wanted to do to set out five (not three) stations. We loaded 1,500 pounds (680 kilograms) of gear and within 10 minutes three of us were off, bound for the ice shelf. The day was absolutely brilliant. Winds were calm and the temperature above freezing. I recalled the day almost exactly three years earlier when I had last been on the ice shelf and experienced similar weather. It took us a few hours to complete the first installation. While we were working, the Otter returned to the Main Camp and returned with Mike Shortt, our team member from the British Antarctic Survey, who had joined our group to make special radar measurements that, when repeated at precisely the same spots next year, will be able to determine the local rate of basal melt. We were done by mid-afternoon, so we returned to Main Camp, picked up a similar pile of gear for the second installation and were successful in getting that established, returning to camp for a late dinner. It was a heady achievement and everyone shared in the joy of it. We had been in Antarctica for five weeks. Finally, we had some science to show for the time.

Our dinner respite was brief. We felt we had a good shot at getting our remaining three stations in the next day, but we had to complete the pre-fabrication on each of them. Oh yes, tomorrow was also going to be the day the Hercules helicopter came. This was the first Herc since we arrived a week earlier. It would not have the much-hoped-for helicopter on it, rather it was coming to deliver camp-take-down material and return six of our field team. The only scientists allowed to remain were the four who were putting in the stations. The others had worked all day reorganizing our cargo into pieces that either stayed for the winter, or returned to McMurdo and home institutions. It was a big job. Everyone worked well into the night. Some stayed up very late despite the bone-chilling wind to ensure that we were ready for both events the following day.

The forecast called for good weather Tuesday, but when the day began, the fog was thick in the direction of the ice shelf. Not good. It was clear that my three days of Otter were counting down. A delay for weather and we would probably lose the Otter. The other science group at Byrd never wanted to see it go and was very anxious to get it back. Fortunately the Otter crew heard some encouraging words from the weather forecast center (in Charleston, SC) and by 10:30 was willing to try to get back to the ice shelf. We loaded the plane quickly and were airborne inside half an hour. The pilot found a way to skirt the fogbank and to our delight (and considerable relief) found our desired sites sparkling in the sun. Stepping out of the Otter, we were greeted again by warm conditions and very little breeze. Perfect!

The third installation went in without a hitch. It was all I was approved to do, but we had the other two ready and I was not about to stop. We rushed back to Main Camp picked up the fourth kit and had it in place and collecting data three hours later. Because of the late start, the Otter crew was beginning to look at their watches to make sure they did not exceed their allowable hours. Travis, the pilot, told me that if we could install the final site in two hours, he would get us there, but when he said it was time to return, we had to stop right away. Confident of our increasing efficiency, I was game but I got a little concerned when we returned to Main Camp to pick up the final setup and discovered a big smelly Herc sitting in the fueling area. That was the one spot on the entire Antarctic continent where we had to be right then and it was taken! This was the Herc that I had so desperately wanted to bring a helicopter. Instead it sat there in my way, loaded with the remainder of our crew, taking them back to McMurdo without ever being given the chance to do the work they came to do. Out of the way!

The minutes of delay seemed like hours, but the Herc evenutally vacated the spot. We loaded and refueled so quickly we almost beat the Herc into the air. The four of us were all primed to get this final installation done in record time and with the help of the Otter crew, we succeeded with time to spare. That was it; our season was over. Five weeks of plodding, waiting, anticipating, concluded by two hectic days of installing secondary equipment on the ice shelf. Nevertheless, something was far, far, far better than nothing at all. We were exhausted, the camp staff shared our joy once we returned, but again we had to forego a long night of sleep to ensure that we put all the tools and gear we had used the past two days in the right places and that what was to happen to every piece of our equipment was clearly understood by those staying behind to close down the camp. Each piece of winter-over material would have to be carefully arranged on a tall snow berm to (hopefully) survive the long, harsh winter.

The next morning was our last at PIG Main Camp. Another Herc (the next to last for the season) would not come for seven days, so we were permitted to fly with the Twin Otter as it returned to Byrd Station. Much to our amazement, when we arrived there, we were told that a Herc was due in an hour. All we had to do was wait in the galley sipping tea and sampling their excellent baked goods. Three hours after boarding, we were back in McMurdo.