During my visit to the South Pole (see previous posts from my trip here), I had a chance to sit down with Nick Morgan, station chief at the South Pole Atmospheric Research Observatory (ARO), operated by the National Science Foundation and one of five climate Baseline Observatories in the National Oceanic and Atmospheric Administration's Global Monitoring Division. Here's what he had to say about monitoring the air over the South Pole.
Can you explain what goes on at ARO? What are some of the observatory's recent findings?
Basically, what we're doing at ARO is getting baseline levels of the atmosphere, whether it's greenhouse gases, ozone levels, solar radiation, aerosols or other things.
Keep reading for the rest of the interview ...
We're seeing trends such as CO2 [carbon dioxide] rising at a steady rate. The ozone 'hole' is not recovering yet; it's been remaining somewhat steady. But CFCs [chlorofluorocarbons] have actually gone down. So, we're starting to see a decline in CFCs and we're expecting the ozone 'hole' to recover soon after, within the next 10 to 20 years. The replacement -- HCFCs [hydrochlorofluorocarbons] -- are a lot less harmful to ozone than CFCs. Eventually, the Montreal Protocol is supposed to be phasing those out, and hopefully the replacement will be even less destructive to ozone.
What are some of the other things you measure?
We measure multiple greenhouse gases along with CO2, such as methane ... And, then, the aerosols, which are basically anything that water will condense on. These are particles in the air, of a certain size range, that water likes to form cloud droplets onto. We're measuring those because they have a large effect on incoming and outgoing radiation ... So, all of these things that drive climate, we're trying to break them down into simple processes. For example, solar radiation -- there are different ways that solar radiation can reach the Earth. It can be just direct solar radiation or it can be reflected off of particles in the atmosphere and then find the Earth. It can also hit the Earth and reflect off and not even be absorbed at all. We're trying to get baseline levels [of these parameters] and break them down into parts so we can better know what's going on.
I've heard from some studies that temperatures in the stratosphere are slightly cooling. How are these temperatures measured here?
We launch ozonesondes once a week. During the time of the season when the ozone 'hole' forms [strongest from September through December], we launch them two or three times a week to get a better resolution in the data. When we launch an ozonesonde, it measures ozone, frost point, temperature and pressure. That gets sent back down here through a radio signal, and we record it and send the information digitally to Boulder.
The South Pole is known for having the cleanest air on Earth. Can you explain why that is?
... We have the cleanest air down here due to very, very little human influence, and we're very isolated from exposed land, so we're not going to get a lot of dust blowing around ... We have a Clean Air Sector, which extends from grid 340 to grid 110 [grid east-northeast], and the winds are out of that sector about 90 to 95 percent of the time. So that way, the Station here is downwind from all of the things we are trying to measure. Basically, for thousands of miles, there is nothing out there to pollute the air.
So these are some of the most accurate measurements in the world?
... They're accurate at measuring what they're measuring in other places. But down here, we're getting a good baseline level. By the time air gets down here, it's so well mixed that we're getting a really good average of what the Earth's air is like. We're not near a factory that is causing a big spike in our data. Our observatory is one of NOAA's Baseline Observatories, so that's what we're all trying to do -- get the average amounts throughout the world.
How long have you been observing CO2 at the South Pole site? Have there been any CO2 trends here?
We've been observing CO2 at the South Pole for a little over 50 years. It was started during the International Geophysical Year, which was in '57. It was started by Scripps Oceanographic Institute -- Keeling was the pioneer in measuring CO2. NOAA joined in during the 70's ... So, we have two dual projects going on. We do measurements on the same day so we can compare data.
What we're seeing is a pretty steady rise in CO2 every year. In other places, you'll see a lot of variation due to the seasons -- when you have leaves out, they'll absorb a lot of CO2. In the Northern Hemisphere, there's a lot of land and a lot of forests, so you have a lot of up-and-down variation of CO2 throughout the year, annually. And down here, it's much more smoothed out ... just because there's no vegetation down here to uptake CO2. Again, we get a good baseline level of CO2 -- how the world is doing.
What is your background, and why did you become interested in working in Antarctica?
I went to college and studied atmospheric science. Then, I joined the NOAA Corps, which is a uniformed service that supports the National Oceanic and Atmospheric Administration. Our primary purpose is navigating their research vessels and aircraft, and we rotate between positions. I just came from my sea tour and was looking for a short assignment. There are not a lot of weather positions in NOAA Corps, so this was more along the lines of my experience in college. And just for the experience of coming down here ... How many chances do you get to come to the South Pole, and especially winter over? I've heard that only 1,400 people have wintered over down here.
For more information:
South Pole Atmospheric Research Observatory
NOAA Global Monitoring Division research areas
South Pole ozone hole data
Climate Fact: The ozone hole and climate
Carbon cycle science explained
Aerosols and climate change
South Pole webcam: live from ARO