An Interview from Antarctica
CIRES researcher reveals excitement and challenges of fieldwork at the South Pole
From October 2018 to August 2019, CIRES research assistant Zimu Li was in the unforgiving, frozen landscape of Antarctica. Along with fellow CIRES research assistant Ian Geraghty, he has been working to operate custom lidar equipment for CIRES Fellow Xinzhao Chu’s research group. The Chu group harnesses powerful lasers to probe the sky, collecting data about gravity waves, particles in the atmosphere to learn more about Earth’s atmosphere, space and beyond.
For the last 10 months, Li served as the technical lead on both Fe Boltzmann and Na Doppler lidar systems in Arrival Heights Observatory, Antarctica. From their home base at McMurdo Station, Antarctica, Li and Geraghty tirelessly monitored weather conditions for ideal data collection, and made the 30-minute drive to the instrumentation at Arrival Heights whenever possible. The team was able to collect about 1500 hours of lidar data—double the amount of data taken during the 2018 season.
“Li took initiatives to solve problems with the lasers, and diligently worked to watch the sky conditions and turn on lidars for data whenever possible. This is one of the main reasons why the 2019 winter-over students were able to double or even triple the lidar data-collection hours of last year,” said Xinzhao Chu, also a professor of Aerospace Engineering Sciences at CU Boulder.
See below for a Q&A from the ice with Li, who returned home safely from his 10-month mission. Get an insider's look into what it takes to live and work as a scientist at the bottom of the world.
You’ve been in Antarctica for nearly a year—what path led you here?
I’m a PhD student from the University of Science and Technology of China, and I’ve been a visiting researcher here at CU Boulder for the last two years. When I first came here, I actually wasn’t planning on doing this field work in McMurdo. The original plan was for me to learn lidar techniques, and learn how to analyze the lidar data to study the atmosphere from the lab. But after one year here in Boulder, this opportunity presented itself. Dr. Chu was shorthanded on students to do lidar operation in Antarctica—and I had another year in my visiting program, so she asked me if I wanted to go. So, of course I said yes to that opportunity, even though I was nervous! In October of 2018, I made the journey down to McMurdo. It was so interesting and exciting to do this observation in Antarctica, to get the chance to know where all the data comes from, all that data I had been looking at in the lab.
Lidar shooting into the Antarctic night sky. Photo: Danny Hampton, Ian Geraghty, Zimu Li
What is a typical day working in the field at McMurdo and Arrival Heights?
To collect lidar data, we need clear sky—it’s the only way the laser can penetrate the atmosphere. The lidar is very easily blocked by clouds, even very thin clouds. But at McMurdo we don’t have that much clear sky. Dr. Chu’s original goal was to collect 100 hours of data each month. That may not sound like that much for a month, but we have very short periods of time that we can collect data. Some days, we can’t collect data at all, and some days, just a few hours. So the first thing we check is the weather forecast. But the forecast is not always accurate, so we have to go outside and look at the sky every hour to see if we had cloud-free sky. Our most hated words quickly became: “partly cloudy.”
But as soon as we do see clear sky, we drive down to Arrival Heights (where all our instruments were) to turn everything on. It’s about a 30-minute drive. When we get there, we have to open the hatch on the roof, turn on the water that keeps the system from overheating, warm the system up, realign instruments, and clean all the optics to make sure there’s no dust—even a little dust would interfere with the laser. Once everything is on and running, we monitor the data, which may be a couple hours to a couple days. The longest run we did was five days. Someone always has to be monitoring the data, and we are just a team of two people. So we take turns doing 12-hour shifts, either a daytime or nighttime shift, so we can at least have one meal. It’s an exhausting job!
You’ve been working the lidar “night shift” for several months now. Tell us about that.
It’s winter here, so there’s not really a difference between day and night. But the main thing is—it can get very lonely! There’s not anyone but me doing night shifts here. In the summertime it’s very different, there’s more people in Antarctica. The warmer season here brings scientists from all over the world, and it becomes a community of people. But after April, most people are gone for the winter. I also have a different schedule than everyone else. I go to have dinner, then it’s just me alone in the building—in one of the most remote places on the planet. But experiencing the darkest part of nighttime in Antarctica also means I see beautiful auroras in the sky.
Li first arrives on the ice. Photo: Zimu Li
What extreme conditions do you have to deal with in Antarctica?
It’s still pretty much nighttime here, 24 hours a day. The sun hasn’t come over the horizon yet (it will come over the horizon around the time I leave next week). In the middle of the night it will be very dark, and during the day, around noontime the sky gets a bit brighter, and a little blue. It’s also extremely cold here: Around this time of year it can be -50 degrees C. And with windchill, it can feel 20 degrees lower than it is. But interestingly, we had weather expert tell us we actually had the “hottest” temps on record for this time of year, it was around -2 C, the hottest ever recorded for July. It’s also windy—sometimes with a wind speed of 100 knots (115 mph). It can be very scary. We have different designations of weather conditions to tell us if it’s safe to go outside: conditions 1, 2, and 3. When it’s condition 3, people can go outside whenever you want. But when it’s condition 1, nobody should go outside. We’ve seen condition 1 several times, and it can be very scary. Even when it’s just condition 2, it’s hard to stand outside from the wind, it could knock you over.
And what challenges did you face while running the lidar systems?
Being in such harsh conditions, sometimes we get power outages. Unfortunately one of our lasers is very sensitive to the power outages. A lot of noises were added to the laser every time the power outages occurred for the first few times and made the laser get worse and worse. We tried so hard to make the system barely working. Then a new power outage came without warning, we were scared, but this time the laser went back to normal!
This weird thing happened again just before we asked the engineer from the laser company to do a diagnosis for the laser to figure out the problem after another several power outages degraded the laser again. We still don't know what happened, this is the weirdest thing that happened this winter.
What were the most interesting parts of your year in Antarctica?
Mostly all the animals! I saw penguins, whales, and seals—but only during the summertime. But now it’s wintertime so it’s too cold for them and too dark for us to see them. But when we could see them it was very fun. We actually have an “ocean observational tube” here near McMurdo that we can go in: It’s a large clear glass tube that goes into the water. You can go inside and see all the little fish around you. It was amazing to see. I personally just saw fish, but some other people saw penguins and seals. I wasn’t that lucky. But I did get the chance to hear the seals. People here have set up sound detectors under the water, with monitors and a speaker, so when the seals come in we can all hear the sounds they make! The first time I heard it I thought it was some kind of alarm, but then they told me it was the seals.
It was also so interesting experiencing the different seasons here. Winter and summer are so different. In the summer we have almost 1000 people here. So we have fun, hang out and go hiking—but in the winter there’s just over 100 people so we can’t do that.
What’s important about the science you do in Antarctica?
Scientifically speaking, one amazing thing we saw this year was a Sudden Stratospheric Warming (SSW) event. SSW is very rare in the southern hemisphere. And our data around that SSW day shows very impressive patterns on both the stratosphere and lower thermosphere. With our high temporal resolution observation, it will help our community study the atmosphere interaction during SSW. Another science topic I'm working on is a long-term phenomenon called Quasi Biennial Oscillation, which is normally observed at the equatorial region, and is also shown in our 9 years of data. We want to figure out the mechanism that could cause this pattern to propagate far enough to reach the polar region.
So if you ask me what's driven me to spend 10 months in such a harsh environment taking data, I would say the beauty of science. When you see all those beautiful results generated out of the data you collected, everything pays back. Our observations can help people understand the atmosphere which protects us and supports our lives. If we can know it better, we can help all life on Earth.