Approaching the Atmospheric Research Observatory (ARO) at the Amundsen-Scott South Pole Station. (Photo by Hunter Davis)
From November until February, the South Pole is awash in activity.
With only four months to ready the station for the coming winter and fix what broke during the previous one, everyone is consumed with work. The cargo and materials specialists are unloading and organizing 70 C-130 airplanes worth of food, fuel and building supplies.
SOUTH POLE JOURNAL
Refael Klein blogs about his year working and living at the South Pole. Read his earlier posts here.
The carpenters are gutting one of our larger outbuildings and converting it into a new weather balloon inflation facility and the heavy equipment operators are clearing snowdrifts the size of small mountains from the sides of buildings.
Eight meters up, on the roof of the Atmospheric Research Observatory (ARO), you can witness the ebb and flow of each day. Trucks motor from maintenance bays to storage buildings, people hustle from worksites to tool shops to administrative offices, planes land, offload cargo, load cargo and refuel. The world below is in constant motion and stops only for the occasional cigarette or sip of water.
The NOAA Aerosol suite is comprised of four instruments: A CNC particle counter (lower left), a MCPC particle counter (lower right), a nepholometer (center top) used for measuring particle size and distribution and an aetholometer (not pictured) used for measuring black carbon. (Photo by Hunter Davis)
While the logistical dance being performed this morning is captivating, I’m not on top of ARO to lounge and admire the day’s scene as it unfolds around me. Today, I’m setting up a new instrument on behalf of NASA, a sun photometer for studying aerosols.
Aerosols are any type of particulate, liquid or solid, that can be suspended in the atmosphere. They come in a variety of sizes and shapes, and can include everything from sea spray and ice crystals, to dust and smog. Of all the key components effecting climate change, aerosols are the least understood.
As a whole, they tend to reflect solar radiation, having a cooling affect to the planet, but can also — depending on their physical properties — absorb heat energy and warm their surroundings.
To top it all off, aerosols influence cloud formation and their effect on what type, and how, clouds develop, can lead to both warming and cooling trends, as well as effect global precipitation patterns.
NOAA’s Global Monitoring Division has an entire group devoted to studying aerosols, which has instrumentation set up at each of their baseline observatories. At the South Pole, we have three instruments running continuously.
Even though we have a robust system in place, we welcome complementary projects, as it allows us to compare our data to data gathered by different devices, which at the end of the day, helps us ensure the numbers we publish are accurate and truly representative of what’s happening in nature.
The sun photometer at the South Pole is part of NASA’s Aerosol Robotic Network, and is just one of hundreds located around the world. (Photo by Hunter Davis)
Like our instruments, NASA’s sun photometer runs continuously. It’s comprised of three parts: a robotic arm that measures solar irradiance, a computer that controls the robot’s movement, and a laptop that sends off data to scientists and engineers.
The premise behind its function is simple. Aerosols of different types absorb solar radiation in different ways. By measuring the sun’s intensity at various wavelengths, the device can calculate the amount of particulate in the air and get a basic understanding of aerosol size distribution.
Simple instruments that work off basic principles, like NASA’s sun photometer, tend to perform well at the South Pole. Often, these devices are easy to install and maintain.
The first step in any instrument installation is to gather your materials and get organized. I unpack the 36-kilogram (80-pound) black trunk that the sun photometer is packed in and try to get as much of the system set up inside, before I head up to the roof. It’s cold out, minus 39 Celsius (minus 39 Fahrenheit) and windy, so the less time I have to expose my hands to the sub-zero temperatures the better.
There are a series of cables that connect the instrument to the control computer. During my first trip up, I get all the electrical connections staged.
My next trip outside is with the robotic portion of the instrument. For the sun photometer to work properly, it has to be perfectly level. While leveling it in a warmer environment would be trivial, adjusting the metal thumbscrews on its base when you can’t feel your fingers is unimaginably tricky.
WATCH: The roof-top sun photometer at the Atmospheric Research Observatory (ARO) at the Amundsen-Scott South Pole Station.
Each trip to the instrument, I get about three minutes of good work out of my hands. Between the time running back into ARO to warm up and returning to the instrument to adjust its orientation, it takes me close to an hour to get the device sitting evenly.
With the sun photometer level, I finish hooking it up to the computer and begin working through a series of simulations that allow me to evaluate the system’s function. The simulations have the robotic arm move from a neutral position, facing down, to an active position, where it points directly into the sun. If everything is working properly, I should see a pinpoint of light pass through a target and line up with a sensor on the instrument’s body.
When I enter my first command, the instrument turns on and begins to rotate. I’m so excited to see it working that I pump a small fist into the air. As it nears the direction of the sun, I wait in anticipation for it to stop and take its first measurement.
But it’s not my day. My excitement turns to frustration as I watch the instrument rotate past where it is supposed to stop, and point 180 degrees in the opposite direction. I don’t know what to do, but I have sneaking suspicion that I will have to disassemble everything and start from scratch.
Heading back to my desk, I make myself a cup of mint tea and gaze out the window. Winds are whipping over the ice cap, rebuilding drifts that were just plowed yesterday. A flight is supposed to land in an hour and there will be an endless stream of cargo to unload. Summer is a busy time at the South Pole. It doesn’t matter if you’re a scientist, engineer or tradesmen, you only have so much time until the sun sets. I put my coat back on and climb the station’s exterior stairs back to the roof.
It’s going to be a long afternoon.
Look for Refael Klein’s weekly blogs from the South Pole every Tuesday here on Science World.