What’s Darth Vader Doing In Antarctica?
The Dobson was installed in January 1988, and has been in operation since then, albeit with some minor outages for maintenance and upgrade. What does the Dobson do, I hear you ask? Well, it measures the ozone in the atmosphere – perhaps not a great surprise given its full name… I was fortunate to get a chance to operate it; you need to line the instrument up with either the sun or the moon to get a reading. (For those that care: the Dobson compares the strength of two ultraviolet wavelengths - one that isn’t affected by ozone, and one that is partially absorbed by ozone; the quantity of ozone can be determined by looking at the ratio between the two.)
There are five Dobsons in Antarctica, and they are used as a check on satellite ozone measurements. The Arrival Heights Dobson is operated by the New Zealand National Institute of Water and Atmosphere (NIWA), which uploads the data to a number of international databases for scientists to use. And they do use it: in 2013, a journal paper was published by Kuttippurath et al, saying that the ozone hole over the Antarctic was starting to recover. To determine this, they used data from a number of places, including the Arrival Heights Dobson. I think that’s pretty cool! Even cooler – it was a Dobson that was used to first discover the ozone hole, and now the same type of instrument is being used to see the repair of the ozone hole, three decades after we realised there was a problem.
But Arrival Heights isn’t all about the ozone – there’s also the Bruker IFS 125HR Spectrometer (Bruker). Sounds fancy huh? It’s a lot newer than the Dobson, and it measures trace gases in the atmosphere. Again, this instrument needs to be lined up with the sun; the tower you can see in the corner of the room houses mirrors to get a perfect beam of sunlight into the Bruker. And unlike the Dobson (which can use moonlight instead of sunlight), the Bruker needs the sun, so the Antarctic one isn’t usable for several months of the year. But I’m getting side-tracked…
Like the Dobson (and indeed all of the NIWA equipment at Arrival Heights), the results from the Bruker are available for use by the wider scientific community. In 2012, Zeng et al used information from the Bruker to look at pollutants near the surface of the planet – specifically carbon monoxide, ethane, and hydrogen cyanide (aka prussic acid, which sounds lovely). Happily, these were all slowly decreasing from 1997 – 2010. Interestingly, there is large seasonal variation each year, which they believe is caused by bush and forest fires, from as far away as southern Africa, South America, and Indonesia.
I shall leave it there, except for some photos of the wastewater plants, as promised! If you’ve got any questions, ask them in the comments, and I’ll try and answer them .
Scott Base Wasewater Treatment Plant:
McMurdo Station Wastewater Treatment Plant - note the difference in scale!