Posts Tagged ‘Terry’

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Flask Glacier

November 18, 2010

Terry writes from Boulder, CO:

Ted, Jenn, Martin Truffer, and two BAS Twin Otter pilots traveled to Flask Glacier this morning to service AMIGOS-3. I got a call from Jenn at 9:55 this morning, and AMIGOS-3 took the attached images about 10 minutes later. They had made a pass over AMIGOS-2 at Scar Inlet on the remnant Larsen B ice shelf on the way in, but the pilots decided that the surface was unsafe for landing. The recent warm temperatures have exposed many previously snow-covered crevasses near AMIGOS-2.

I got call from Ted at 10:35. He finished the AMIGOS-3 repair and testing of the downward-looking albedometer sensor. I have also verified in the data we received in the last few minutes that the repair was successful. Next, the team is heading to Leppard Glacier to repair the GPS unit there.

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Last day on the ice

March 1, 2010

Note from LARISSA team: our sympathies and best wishes to the people of Conception and Santiago, Chile, and the other damaged areas. The Earth can be mighty and implacable, as well as beautiful. Humanity alone knows compassion, and this is our strength

Terry writes:

Our first evening back on the Nathaniel B Palmer was quiet, calm, and starlit. Orion was setting, head down, in a cloudless southern sky. We were in Andvord Bay on the west side of the Antarctic Peninsula, planning the last few possible installations for the cruise. All of them required helicopter flights over the ridge to the Peninsula’s east side. We could only hope that the weather would be clear enough on both sides to allow that, which so far during the cruise had only happened once, and never while our glaciology group was on the ship.

Terry climbed ten feet up the tower to install the replacement camera.

The next morning, Sunday February 21, Ted woke me at 6:15 with the news that we had clear skies around the ship. Erin and Martin’s trip to Foyn Point to install a seismometer was on. Then he said I should get ready to replace the AMIGOS camera at Scar Inlet later that morning as well–even though that was not planned at all. Erin and Martin took off in Barry James’s helicopter around 7:45 while Ronald provided me with some tips on how to test the camera after installation, and how to set up pointing for pictures. But by 8:15 Erin was back on the ship telling us they had turned around due to low clouds on the east side. They were going to try again in an hour or so. This gave me extra time to consolidate the clothing, tools, and climbing equipment I’d need to perform the replacement. They did indeed leave again on Barry’s helo around 10:45, and by 12:30 I had wolfed down a quick lunch, had my replacement camera, my computer, and the rest of my gear loaded onto Chris Dean’s helo. I climbed into the front passenger seat and got strapped in. This would be the third helo flight of my life, but my first one in the forward seat. The feeling up front was somewhere between space capsule and soap bubble.

We lifted off the pad in bright sunshine, the blue waters of the fjord peppered with house-sized icebergs calved from the surrounding glaciers. We flew southeast above Bagshawe Glacier, passing a huge black wall of smooth vertical rock wall laced with an intricate network of snowy cracks. Below us lay a blue-white quilt of ice and snow with a patchwork of seracs (standing ice blocks) and their intervening crevasses. The helo approached the summit of the brilliant Bruce Plateau which at first loomed above us as an insurmountable hurdle (picture), but then flattened into a sloping plane as we came closer. A quick look behind showed an ominous sea of fog approaching our tiny orange ship from the northwest. I feared we’d be racing a closing weather window: the helos had already lost one such race, and the pilot and two explorers had camped on a rocky beach for three days as a result.

We stopped first at Foyn Point to pick up Erin, who would serve as mountaineer at our next stop at Scar Inlet. Just as we landed at Scar Inlet, we received word from the NB Palmer that the fog was only a few miles from the ship. Chris responded that we would leave in about an hour.

We were worried about the crevasse risk, given our experiences on the day we left the AMIGOS site.  Since then the Scar Inlet AMIGOS had been reporting afternoon temperatures as high as 6 degrees Celsius (about 43 degrees Fahrenheit). Warm temperatures can soften and weaken the snow pack covering hidden crevasses, such as the ones we found during the deployment. So immediately upon stepping out of her seat, Erin anchored her rope to the helo skid and then probed with her ice axe outside my door. The top 12 inches or so seemed fairly resistant to probing, so she then instructed me to step out of my seat and to clip into the prussic (a sliding loop of smaller gauge rope) she had rigged for me on her rope. After stumbling for a moment with the prussic, I gingerly stepped into each of her leading footprints until we reached the tower. The whole thing was as close to a space-walk as you can get, I think, on this side of space anyway.

Amazingly, we managed to test the replacement camera, climb ten feet up the tower, and install it, in a little over an hour. The tower moved a bit with both of us hanging on it, but we were chosen to perform this task because we were the lightest-weight team members.

Our return flight went northwesterly, straight back to the ship in Andvord Bay and directly over the outlets of several glaciers that flow east into the Larsen B Embayment. I pulled out a 30 meter resolution Landsat satellite image map from my computer case so I could identify and call out each glacier as we flew over it:  Flask, Stubb, Starbuck, Rachel, Pequod, Melville, Mapple, and Crane. I found it was relatively easy to match up individual ground features seen out my window with the corresponding features from the image map: a distinctive line of peaks here, a tributary glacier flowing in there, etc. The weather was still very clear where we were, although I did notice some fog obscuring the sides of Crane Glacier where I was hoping to see the “trim line” that marks the previous level of ice before the dramatic drawdown of the glacier that has occurred since 2002. I was so busy looking for the trim line on Crane that I completely missed noticing the calving front that was clearly visible from the our left side seats as revealed by Erin’s photos. Oh well, maybe next time.

Later that evening Ronald and I were able to confirm that images from the Scar Inlet AMIGOS were indeed being received and that the camera seemed to be working perfectly. And although we needed to adjust the camera positions (which we can do remotely), it turns out that just by chance one of the views appears to be looking directly up Flask Glacier, which is one that we’ll probably keep.

We did it. We used every resource in the program to do it, but we did it: three AMIGOS, and two GPS, sitting on some of the most dynamic, vulnerable ice on Earth.  Now we’re sailing north towards Punta Arenas, packed up, and wondering what’s next.

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Flask Glacier and Scar Inlet

February 18, 2010

Ted writes:

The LARISSA Glaciology team continued to get things done in the Larsen B embayment over the past week, but at this time of year the region has a very frustrating weather pattern.  Snow, fog, mist, and even drizzle can shroud the area for a solid week.

The majestic Melville Coast emerges from a thinning haze.

After several days of heavy snow at the Flask AMIGOS site, we awoke to a gradually clearing mist on February 13, and prepared to move fast. Terry Haran and Ronald Ross returned briefly to the previous site at the crest of the ice cap, to re-connect a sensor that failed during our last hour of installation there. Meanwhile I, Martin Truffer, and  Erin Pettit, moved to a second glacier, the wide but relatively smooth Leppard Glacier, to install a continuous-monitoring GPS system.

By flight time the weather was excellent: clear, sunny, and dry with light winds. The flights went perfectly, and within one hour we had the teams at the two sites and making progress. But through it all, to our east, we could see a grey formless shape, a hazy pancake of fog lurking over the shelf. We worked like an assembly line on the Leppard Glacier GPS station, the team barely needed to speak as we worked: this tool here; that method works best for this, here’s this idea to avoid the problem last time, but the fog rose like some inexorable hand, slithering up the glacial valley. How long would it be this time? How long would we be stuck? Worse, we were now a split team again. Terry and Ronald could not rejoin us at the next site, the Scar Inlet Shelf, the lower site, in the center of the fog.

The Scar Inlet is the last vestige of the Larsen B ice shelf—less than 20 percent of a shelf that in the 1980s rivaled the size of Connecticut. Scar Inlet is the southernmost bay of the shelf, and therefore in a slightly cooler climate that the areas that broke up earlier. Its potential for collapse in the next few years, should warming continue even a little, is the driving motivation for our work. Can we get instruments on it ahead of time, and track both the processes of break-up, and the response of the glaciers? In 2002, both of these were stunning: a massive shattering disintegration of a thousand square miles of shelf ice, 700 feet thick, in the space of just a few weeks, followed immediately by a surge of all the glaciers flowing into the affected area, to as much as six times their speed prior to the event. Only the Scar Inlet ice remained; only the Scar Inlet glaciers were un-affected. Scar Inlet stands at the front line of climate change in Antarctica.

As we hunkered down in our tents on Leppard Glacier on the night of February 13, fog and darkness shrank the world to just two dome tents.  Scar Inlet seemed beyond our grasp, a prisoner of a colder, damper summer than most.

February 14 was our lucky day. The fog retreated back down the valley, and the airplane was there within 90 minutes of our weather call. Terry and Ronald were dropped off at the new site first and we joined them by early afternoon. It was by no means a full retreat of the mist, but there were enough ragged holes in the blanket covering Scar Inlet that the pilots managed to get the flights in. The AMIGOS tower was already underway, like a mechanical Frankenstein, slowly coming to life.  As they left, the lead pilot shook his head: “I’m worried about this fog. You guys are going to be here for weeks.”

As I said, Scar Inlet is on the verge of collapse, rent with shallowly buried crevasses, because melt in summer removes nearly all the winter snowfall. But we had no idea just how precarious the situation was. As part of building camp, Terry dug a pit, to “accumulate food wastes,” shall we say, and nearly lost the shovel down a narrow crack about 50 feet from the tents. We took it seriously. Erin put on skis and her harness, and with Martin watching, she probed the area around camp. We found one part of the crevasse that might be wide enough to pose a hazard, and marked it. Overall, the camp seemed safe. Traversing with the radar that evening, we probed on skis for 6 kilometers (4 miles) to the north, and found no more weak areas. Needless to say, we dug a different pit.

Erin probes the ice fracture outside of camp.

February 15 was cool, dismal, even dank, as the fog and clouds closed in again. At this low altitude, just barely above sea level, the air felt heavy and wet. We had seen nothing beyond the runway flags, except occasionally the lowest parts of hazy rocks in the distance. For the most part, we were once again floating in an infinite grey ball, with no horizon. But we worked continuously to get the AMIGOS station in, and by 9 p.m., we had raised the tower and secured it, digging three deep pits and a central large pit for the anchors and the tower base.

The next day, we sensed a change. The mist was thinning. The sun was still obscured, but too bright to look at. We saw shadows for the first time in days. Not quite flying conditions, but close. We radioed a report on the trend to the pilots at Rothera Station, and then took off quickly for a second radar survey.

About a mile out of camp, it happened. Behind us as we skied, the fog began to thin to nothingness, and a stupendous landscape emerged. Martin was the first to notice it, as he knelt to adjust the radar system. It was as if we had been standing in a national park, a world heritage site, that had been hidden behind curtains. The satellite images could never do this justice: Leppard and Flask glaciers flowed down toward us, past a giant rampart of rocky peaks to merge at our feet into a vast plate of ice. In the harnesses, we were giddy: we stopped, snapping pictures, laughing and joking. Our camp seemed like a few fallen toys on the snow at the foot of the range and glaciers. I’m sorry: I just could not get it all to fit into the camera. The majesty of the place was beyond recording.

Ted and Martin Truffer ski across Scar Inlet.

But February 16 was to be a roller-coaster day. As we skied back to camp, looking forward to a return to Rothera, we noticed something odd about the AMIGOS tower in the distance. There was a large black lump clinging to the side of it. Skiing closer, we could see that Terry was near the top of the tower. Something was wrong.

As we got to camp, we learned that the camera on the AMIGOS had failed sometime after we hauled the tower upright. Fixing it would require hours, and even that was not certain; and the planes would arrive within 45 minutes, and they could not wait.

Wow. To have all this to look at, and all the events that might indicate an impending breakup, and no eyes on the AMIGOS. Ronald informed us that there was no way he could fix it out here, and so dejectedly, we removed the camera from the system.

The planes arrived. The distraction of the broken camera, and our long ski back from the radar traverse meant that we were completely unprepared for them. Camp was still scattered and unpacked. But the pilots pitched in, (I want to say: outstanding pilots, Richie Cameron and Dave Edenborough, both in flying and in supporting the science work), and began to help us pack the two aircraft.

That is when the second stunning event happened. We had been at the camp for three days, stomping around everywhere, and had skied for kilometers, finding just one narrow crack. But as one of the pilots dragged some heavy cases across the snow, we heard a shout – and turned to see him waist deep in a 2-foot-wide crevasse. The chasm was nearly black at the bottom, at least 20 feet; it was a “dead” crevasse, formed upstream, and the sides were coated with icicles and frozen rivulets of water from previous summers. The pilot was shaken, unhurt, but the shock of it drew us down even further. Martin probed a safer route, and the mountaineers and I did the rest of the packing, on skis for safety.

The song that came to mind on takeoff: “Whipping Post” by Eric Clapton. But as we flew, and talked things over, a new resolve came to us. We could fix the camera with a quick helo flight and appropriate precautions. And crevasses comes with the territory of exploring active places on ice, places that are changing as climate changes.  With one more week on the ship, we might, just might, be able to put in another station or two, on some of the most interesting ice terrain on Earth

Erin found some food in her pack, crackers ground nearly into gravel, chocolate, and some cheese. It would have been trash by any ordinary standard, but by this point Terry and I were in full ‘field mode’: this was food, and we were hungry.

Terry and Ted enjoy a much-needed snack.

By the time we landed, the song had switched to “Fanfare for the Common Man.” That is how to fly over the Peninsula landscape.  We are now waiting for a flight from the British base to rejoin our colleagues aboard the Palmer.

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Update from the ice field

December 14, 2009

Terry Haran is still in Boulder, Colorado. He’ll be departing on Christmas Eve for Punta Arenas (shortly after Ted returns home for a short holiday visit) to participate in the second leg of the trip.

Terry writes:
The team is currently near the summit divide of the Bruce Plateau, conducting an Ice Penetrating  Radar (IPR) survey. The goal of the survey is to help determine the optimum location for retrieving an ice core. Ellen Moseley-Thompson and a team from the Byrd Polar Research Center (BPRC) plan to drill the core in January and February 2011. Their team will deploy to the to the same location as soon as the IPR team is finished.

The purpose of the ice core is to characterize the paleoclimatology of the LARISSA study area going back in time as far as possible, hopefully as much as 10,000 years or so. The ideal location would have a depth to bedrock of about 500 meters (about the maximum depth that the BPRC team will be able to drill in the time alloted to them), and would have a relatively smooth bedrock surface.

Ted’s team also hopes the IPR survey can characterize the inter-annual layering found in the upper 100 to 200 meters of the much younger snow cover known as “firn” that is in the process of compacting to eventually become ice. The ideal layering found at the ice core site would be horizontal and uniform with little evidence of firn motion downhill from the summit ridge.

Over the weekend, we got a few updates from the field. I spoke to Ted on the phone, and he said they had surveyed about 60 kilometers with the 5 MHz (deep) radar and were getting good data with it. They think they’ve accomplished all they need to with this radar.

In the next few days before the team return to Rothera Station, they were hoping to resurvey some lines with the 25 MHz (medium depth) radar and to obtain some higher precision differential GPS data for some survey markers than they had geolocated with their hand-held GPS. However, a powerful storm was on its way, so they decided to spend Sunday preparing for the storm and staying in their tents analyzing the 5 MHz data they have collected.

The latest update we received, from the LARISSA operations team, informed us that the team is ready for pickup. However, because of bad weather that’s expected to stick around for the next couple days, they might not be able to get a plane in for a few more days.

The MODIS images below show the location of the team on the Antarctic Peninsula

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