We smashed it.
Our team is back at South Pole Station after a highly successful 88S Traverse. We budgeted 16 to 19 days for the traverse, but we returned to station after just 15 days. Our science instrumentation and the vehicles performed with only minor hiccups, and in general, any problems that arose were solved quickly.
The campaign by the numbers: 750 km (or 466 miles) of ground traverse; 15 days; 4 people; 2 PistenBullys; 4 corner cube reflector arrays; many snack, including an irrational number of Slim Jims; ~3 lbs of coffee; 1 giant tub of ice cream; and way too much CCR, Ozzy, and Styx.
But first – 4 days to get to our study area! To reach the southern extent of the ICESat-2 ground tracks at 88 degrees latitude, where we’ll take ground measurements to compare with future satellite data, we had to drive 220 km (137 miles) from the South Pole. We collected GPS elevation data along the way, in part to get ourselves up to speed with the day-to-day business of data collection and in part because there is very limited ground-based elevation data in this region.
The first 110 km (68 miles) of this was on the established, groomed, South Pole Traverse route, which had been driven three times this season as teams delivered fuel to South Pole Station. But after that, we were on our own…
We turned left off of the South Pole Traverse route and began breaking new ground. After another 110 km, we were on the 88S line of latitude!
Almost instantly, we arrived at a point where Tom and I wanted to deploy an array of corner cube retroreflectors (CCRs), which are made of specialized glass that will strongly reflect the transmitted signal from ICESat-2. These points of strong reflection will be used to validate the pointing of ICESat-2.
The CCRs are insanely small, smaller than your pinky nail. Setting up the first array of 6 CCRs took about half a day, as we mounted the CCRs on the top of bamboo poles and then precisely located the position of the bamboo poles by occupying the site of each pole with a survey-quality GPS for 20 minutes. Since most of this was accomplished outside, you can imagine that this was a pretty cold morning. Ultimately, we deployed 4 CCR arrays along the 88S route.
With the exception of the areas associated with the CCR arrays (and yes, every time I say ‘CCR’, Tom sings a John Fogerty classic; it’s true even in his reading of this), the bulk of our days were consumed with driving. We averaged about 60 km (37 miles) per day, at a breakneck speed of about 9 km/hr (5.6 mph).
And as with any road trip, we consumed a lot of road snacks, including chips, jerky, and in the case of our mountaineer Forrest, many, many Slim Jims.
After about a week on the 88S line of latitude, we reached a point where we had collected our goal: 300 km (186 miles) of ground-based elevation data for direct comparison with ICESat-2 elevation data. Forrest fired up Ozzy’s ‘Mama, I’m Coming Home’ in his PistenBully and we made our second left turn, toward Pole.
From 88S, we again traveled 220 km to traverse from our study area to Pole. We continued to collect data along this stretch, but our focus turned to the tired PistenBullys, which are 17 years old and not accustomed to two straight weeks of intense usage. Our incredible mechanic Chad kept an eye on these and helped to nurse them home.
We did so well, that I was overly conservative on consumption of really good coffee: I made Tom drink mediocre coffee for about a week, before I felt confident that the really good coffee would last the whole traverse. For this, Tom, I am eternally sorry.
Hey Eileen: Mama, I’m coming home.
-Kelly and Tom
By Christine Dow
We have arrived back safe and sound after 11 days crossing the Southern Ocean. Our exit from Jang Bogo involved one last (very short) helicopter ride taking us to the Araon icebreaker so that they didn’t have to re-break ice to get back into port. I stayed up till the wee hours on the top deck watching us motoring away from my home for the last month, pushing large chunks of sea ice out the way. Some Adélie penguins were also witness to our departure along with snow and cape petrels diving and swooping around the wave tops. It was a very idyllic sight and I was sad to say goodbye to the Antarctic (until next time).
Onward ho. Over the next few days we crashed and bumped our way through the sea ice. This was a good chance to get used to the (very) rolly motion of the boat. Icebreakers are designed with highly rounded keels, excellent for smashing through ice packs but not so great on the stomach. A very good distraction was the on-board table tennis table. Many doubles games were played over the course of the voyage, some more successful than others depending on whether the boat allowed both balls and players to be on a sensible trajectory.
After two days, we were almost out of the sea ice pack when we suddenly had to turn around and return south. There had been a distress call from a fishing boat stuck in the ice and R/V Araon went to the rescue. We successfully hauled the boat free from the ice that it had become wedged on and escorted them to a region easier to navigate through. On the return journey we also stopped to collect some long sediment cores that the Korean scientists will analyze later.
The timing of our journey meant that we had Christmas on board the boat. Our party was on Christmas Eve and involved a veritable feast – the chefs had been very busy all day kindly preparing this for us. One of the Korean scientists also played some clarinet and saxophone music to get us in the Christmassy mood. We even had a Christmas tree, lashed to a railing to stop it flying all over the place.
On the 11th day of our journey we could see land. It was very strange to see trees and green again after so long with just hues of blue and white. We had also been slowly getting used to the dark as we moved north following our time in 24-hour daylight; the first sunset of the voyage had been spectacular with giant albatross swooping behind the boat. I watched as we finally docked at the port of Lyttleton in New Zealand, feeling that “normal” life would be a little surreal after our adventure. It was time to say goodbye to our friends and colleagues and go home, just in time for the New Year. After such a trip it’s not surprising that one of my resolutions for the new year is to get back to the frozen continent…some day.
By Christine Dow
The big day had arrived. We were due to fly to our tiltmeters to collect the data that they had been gathering for two weeks. once this was the first time we had ever set these instruments up in the field, all fingers were crossed that we had been precise enough in initially leveling the meters so the data were in range and also that the solar panels hadn’t ended up covered in snow.
We had a spectacular flight, cutting over the end of Priestley Glacier and skirting helicopter-sized crevasses on the mountain behind our field site. Despite a bit of wind on the Nansen ice shelf, it was as calm on the Comein Glacier as it has always been for our visits. It’s such a peaceful, sheltered spot that I feel a holiday cottage wouldn’t be amiss. Perhaps too long of a commute for an average Friday afternoon, however.
One of the tiltmeters (which are in black boxes) had become exposed and, because black materials absorb heat whereas white materials reflect it, had caused a bit of local melt which had trickled down the side of the box and refrozen. The upshot of this was that the entire box, battery, and straps were encased in some pretty solid ice. Fun! Commence some delicate hacking with ice axes so that we didn’t snap the wires coming out of the box. Finally having reached the interior, we nervously extracted the SD card and Ryan pulled the data off onto the computer. Success! Some excellent (and exciting) looking data showing tidal cycles. Tiltmeter two was easier because it hadn’t caused local melt of the snow so we could quickly retrieve the data. Again, some very interesting outputs. We want to thank John Leeman, an engineer from Penn State, for building us some happily working tiltmeters. Of course having disturbed the tiltmeters I had to reset them back to full level, which required sitting for 10 minutes enjoying the view while very delicately adjusting the little leveling legs.
We had just enough time to collect data from one of the GPS closest to the tiltmeters. All looked well apart from our tethers, which had come loose because of melt on the surface. We had one bamboo tether and one metal peg. The metal had heated up and melted a groove in the ice as it was pulled along, whereas the bamboo had stayed where it was supposed to. We tightened the wire as much as possible but we would have to return to this site with some more bamboo later.
Dinner back at base was a happy affair, having achieved success for at least three of seven of our instruments. The chefs had even made some pizza for us, which was a nice treat. The only unfortunate aspect of the day was that I had forgotten that in areas with 24 hour sunshine and highly reflective snow surfaces it is essential to put sunscreen up your nose as well as on it. Burnt nostrils are not fun, but they’re worth it for some nice data.
By Ryan Walker
Our second day of installing equipment was on November 21. After a cloudy day off, we had perfect sunny weather.
We began by installing our two tilt meters at Comein Glacier, which flows into the Nansen Ice Shelf through a small inlet just north of the much larger Reeves Glacier. Most of an ice shelf floats freely up and down with the ocean tides, and the ice only flexes in a relatively narrow band between the floating ice shelf and the grounded glaciers that flow into the shelf. We chose this location (about 35 miles upstream of the ice shelf front) because the flexure zone is particularly wide (over three miles) and there is a broad strip of over 900 yards of ice that floats at high tide and rests on the ground at low tide. (We know this thanks to satellites that measure the height of the ice surface using lasers or radar, and to comparisons between satellite radar images that detect ice motion.) As it turned out, this area is the most spectacular place we’ve yet visited, surrounded by gleaming white snow- and ice-covered peaks.
Installing tilt meters is rather tricky, since the instrument has to be almost perfectly level. After two Korea Polar Research Institute safety guides checked the area for crevasses (large cracks in the ice), we dug through about two feet of snow before finding solid ice. To keep the tilt meter level, we constructed a table from a piece of plywood supported by three aluminum pipes drilled into the ice. The pipes passed through holes drilled in the plywood, which rested on hose clamps fastened around the pipes. By adjusting the hose clamps, we leveled the plywood before placing the plastic case containing the tilt meter on top of the table. The tilt meter itself has a triangular base with three adjustable screws so it can be leveled on top of a flat plate at the bottom of the case. To do this, I had to attach a cable from the tilt meter to my computer to get readouts of the angles while Christine very carefully adjusted the screws. Once we were satisfied that the instrument was level, we hooked up a solar panel and battery for power, just as we did for the GPS stations. Finally, we buried the case and table in the snow to prevent any melting of the ice supporting the table, which could put the instrument out of level.
After sandwiches and coffee in beautiful sunny weather (certainly the most scenic picnic lunch I’ve ever had), we took some time for a school outreach project that Christine will tell you about. Then we flew back out onto the Nansen Ice Shelf (which is much windier) and installed our two remaining GPS stations with no trouble (other than a chilly half hour waiting for the helicopter to return) to complete a successful day in the field. Now we need to wait about two weeks before collecting data, so that we can see what happens to the shelf as the ocean tides go through a full cycle from spring (largest difference between high and low tide) to neap (lowest difference).
Christine says: I’m involved in a program coordinated by the United Kingdom Polar Network called “The Antarctica Day Flags Initiative”. School classes design flags for Antarctica Day (which is December 1, the anniversary of the signing of the Antarctic Treaty in 1959) and then scientists and researchers take them to the Antarctic and take photos of them out in the field. I had 21 flags from two schools (Yardley Hastings and Northrepps Primary) so we attached these to poles and took some pictures in front of some beautiful icy cliffs with our Korean colleagues.
By Brian Walker
November 19th — After the final cargo flight on November 17th, we finally had all our equipment and could prepare for installation. This wasn’t without some drama, as we initially received only four batteries and various pipes, but none of the actual instruments. After a few tense hours of emailing, we found that the rest of our gear had accidentally been sent to the Italian Mario Zucchelli Station, so we would be fine. (Zucchelli and Jang Bogo are within sight of each other, about six miles apart on opposite sides of a bay which is currently frozen over, so the Italians and Koreans share flights.) Christine joined a group taking a tractor drive over to Zucchelli the next day and retrieved the misplaced equipment. After a long day of testing our GPS units outside in high winds and organizing the equipment in a slightly cramped laboratory building, we were ready to go the next morning.
We were fortunate to begin the day with good weather, and due to a slow schedule, we had both helicopters. This allowed four Korea Polar Research Institute (KOPRI) personnel, including a safety guide, to join us. With their help, we were able to install the GPS stations much more quickly (sometimes in as little as half an hour) than we would have been able to manage by ourselves.
Our GPS systems include a disk-shaped antenna that receives satellite signals and a computerized unit that processes and records data. With good processing after the stations are retrieved, we should get positions accurate to about half an inch, which will allow us to study the vertical and horizontal motion of the ice shelf, especially the effect of ocean tides. The stations also include a solar panel and a 12-volt battery (essentially a car battery) for power. To install a station, we wire the receiver (the computer), which stays inside a weatherproof plastic box the size of a carry-on suitcase, to the antenna, solar panel, and battery. The antenna is mounted about five feet off the ground on the end of an eight-foot steel pole sunk into a three-foot drilled hole. The solar panel is mounted on a shorter pole that also passes through the carrying handle of the plastic receiver box, so that it’s much harder for the receiver to blow away — a constant threat with a slippery ice surface and high winds. Wires attached to anchors drilled into the ice secure the solar panel, and the battery is firmly strapped to the receiver box. Where necessary, we used ice axes to chop roughly six-inch deep holes for the receiver box and battery to rest in. For the poles and anchors, the final step was to pour water into their holes, which instantly froze and locked them into place.
We had planned on installing two GPS stations, then returning to Jang Bogo to reload the helicopters and installing the remaining three in the afternoon. However, heavy cloud cover started to blow in as we installed the first station of the afternoon. Clouds diffuse sunlight and create an effect called “flat light”, in which depth perception of white snow and ice surfaces becomes difficult. This obviously isn’t good for flying helicopters, so we returned to the station early to be safe. It was still a good day, with three GPS stations successfully installed. Two GPS stations and two tilt meters remain to be installed when weather and flight schedules permit.