Our 2023-24 field season has concluded! And in fact, Dave and Wenhua redeployed on 10 January. This post will be a wrap-up of our last few weeks on the ice, going over the final site visits we did. Spoiler alert, we had one of our longest stretches of cancelations trying to go to Emma: 22 days in a row of weather/priority cancelation! But, another spoiler: we ended up flying to Emma!
After our visit to Sabrina, we took a Mattracks on 11 December (a pickup truck where the wheels are replaced with tracks) to our 3 sites by the airfields: Phoenix, Willie Field, and Sarah. At Phoenix, we wanted to dig up the power system and replace the batteries since it was failing at the end of this past winter. For the collocated Willie Field and Sarah, we wanted to remove the two AWS and relocate them to be right off the airfield road (a few years ago, the airfield road was moved). That day ended up being one big workout, as all 3 power systems were buried and encased in ice. Not to mention the work of removing 2 AWS. At least it was a gorgeous, sunny, and warm day.
Then the delays began. We had two more Otter flights we wanted to do, to remove Emma and raise Lettau, but those are far flights. Both require stopping at a fuel cache en route to refuel, which makes it a longer day and means weather has to be good at more places for longer. Both sites are on the far southern end of the Ross Ice Shelf, with Emma being a bit further than Lettau.
Combine competing with the weather with competing with other teams requiring the Otter (a science camp put-in was higher priority, and they were delayed as long as us but fortunately got their flight and got as much work done as they could!), and we ended up waiting 22 days for our flight to Emma!
It was discovered that, this past October, Lettau’s wind monitor was reporting bad data and was suspected broken, so we wanted to go to Emma before Lettau because we hoped to replace Lettau’s wind monitor with Emma’s. After a week of waiting, we decided that we could use Willie Field’s wind monitor at Lettau, so we decided to try for Lettau before Emma, and on 19 December we made it to Lettau! First, of course, we had to stop at the fuel cache.
It was impressive that after such a long time between full servicing, the only big issues were snow accumulation (typical) and the wind monitor falling off (moving parts are always more susceptible to breaking). The batteries in the power system were starting to drain, so we knew we wanted to replace it. We were hopeful that we could dig up the old power system, but even with three morale trippers along with us to help, we couldn’t recover it given the limited ground time.
We raised the station with a 7′ tower section, and wow that was difficult to install! The legs of the new one didn’t quite line up with the existing one, but after some TLC (tough love and cursing) we got it on. Then we reinstalled all instrumentation, plugged in the new power system, and confirmed transmissions. Another successful raise in the books.
After the high of finishing Lettau came two weeks of waiting and wondering whether we would be able to get out to Emma before our scheduled redeployment on 8 January. Our last day that we could try was 5 January, since we would then need to pack up and submit our cargo to be shipped north, then clean up the lab and prep for our departure. It came down to the wire, but we were able to get to Emma on 4 January!
Our mission on this visit: remove everything and leave no trace. Since we have some AWS “nearby” on the southern Ross Ice Shelf, our group determined we didn’t need Emma installed anymore. It was functioning perfectly fine, so its instruments can be reused, either at existing sites or to all be reinstalled at a new location. We also wanted to remove the tower sections and as much of the guy chains as we could, both for reuse and to not leave equipment in the field.
And that concludes the field work Wenhua and I did this field season. It was fun working with Wenhua, and we had a successful season, too. We serviced 18 out of the planned 21 AWS/PCWS!
Here’s to another good field season!
Cheers,
Dave