On the Ice

Two site visits and a New Year

Happy New Year everyone! Time for another field season update. About a week and a half ago, Lee and I visited our first AWS of the season! But it wasn’t the AWS we were looking for… And on New Year’s Eve we got to our second site. We topped off that with some New Year’s celebrations this past weekend, including Icestock. But first…

On 23 December, Lee and I hitched a ride with Nikko from UNAVCO (University NAVSTAR Consortium, focusing on GPS systems) out on the snow road on the McMurdo Ice Shelf to the airfields in hopes of us visiting our Willie Field AWS and collocated Sarah PCWS. Nikko wanted to go to the end of the snow road at Phoenix Airfield where his group has some instrumentation. We also have an AWS, Phoenix, there. It had been quite warm in the week leading up to that day, with highs in the 40s F, and with the warm temperatures, the snow gets very soft on the ice shelf. It then becomes difficult, and damaging to the snow road, to drive wheeled vehicles out to the airfields… PistenBully to the rescue! This is a small, cube-shaped tracked vehicle that is much more kind to the snow road. Nikko got trained to drive a PistenBully, since it’s not like driving a normal car or truck, and he offered us a ride and to stop at our sites on the way.

We were planning to remove the enclosures on Willie Field and Sarah to replace some sensors and electronics. Since Willie Field was installed in 1992, it was located just off the snow road ~50 feet and near Willie Field Airfield, so it would be very convenient to visit. All it would take is a drive on the road and we could service it. As we were tooling along on the snow road in the PistenBully (our average speed was about 10 mph), Lee and I were looking to the left when we thought Willie Field AWS would be visible. But we never saw it… We kept driving and looking, with no luck, and eventually got to the end of the snow road at Phoenix Airfield. Scratching our heads, we took some pictures of our AWS and removed the enclosure so we could take it back to the lab and replace the pressure sensor.

Phoenix AWS, the PistenBully, Lee, and Nikko.

Once the quick half hour visit was done at Phoenix, we headed back to Willie Field Airfield to search for our site. Lee plugged in the coordinates and, as we approached Willie Field Airfield, we noticed the arrow pointing to the left instead of the right where we thought it would be. Eventually, as we looked left, we saw both Willie Field AWS and Sarah in the distance. We figured that they must have moved the location of the snow road! Rather than us just trekking straight out to our sites, we decided we would head back to town and find out why the snow road was moved. For all we knew, there were some cracks in the ice around our site that would have made it dangerous to visit. We later found out that the road was moved because it was getting too close to the edge of the McMurdo Ice Shelf. The surface conditions around our AWS are safe, so we plan to take snow machines to visit them later this season. That day turned out to be more interesting than we had planned.

On New Year’s Eve, we took a helicopter to visit White Island AWS, located on White Island just south of McMurdo. It felt great to finally get on an airframe to do some field work. We brought Madeline from PASSCAL (Portable Array Seismic Studies of the Continental Lithosphere) with us to show her our AWS and have an extra hand in the field. White Island had stopped transmitting a few months ago. It’s on the top of Mt. Heine, the tallest peak on the island, is on rock, and can get very windy. Our two best guesses as to why were 1) a broken antenna or antenna cable, and 2) an issue with the power system. When we arrived, it was a sunny and fairly warm day with temperatures around 28 F, but it was pretty windy, which made it feel colder. We don’t know how windy, however, because the wind monitor was completely busted. The strong winds had done a number on it, completely breaking off the tail fin and the propeller. We will have to eventually revisit the site to install a new Taylor high wind system. We also noticed that the antenna cable was dangling off the tower, disconnected from the antenna. The wind strikes again. We checked the power system, and that was fine. We replaced the antenna cable and verified the station was transmitting. Despite the wind issues, we got White Island back up and running! A successful visit.

White Island AWS when we arrived.

This New Year’s weekend was full of festivities, including the Holiday Party on New Year’s Eve (delayed because of level blue COVID precautions during Christmas) and Icestock on New Year’s Day. Icestock is a half-day long music festival, with a chili cookout thrown in, showcasing the incredible musical talent here in McMurdo. I love live music, so this was something I had been looking forward to for a long time.

Icestock 2022

Starting last week, we were also put on the Twin Otter schedule to go to Alexander Tall Tower!. This is a pleasant surprise, since this Otter is working out of New Zealand’s Scott Base. The two USAP Otters are at WAIS and/or South Pole until later in January. We need two visits to Tall Tower!, the first of which by just the riggers so they can do tower maintenance to make sure the tower is safely standing. Since it’s ~100 feet tall, it takes much more maintenance than our ~12 foot towers. The second visit to Tall Tower! Will involve us digging out and raising the power system while the riggers raise the instrumentation on the tower. Hopefully this week we can get out there.



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