Snow Pit Sampling
One part of my job is to go to the CASLab (Clean Air Lab) everyday to change a small filter (or at least one of the three of us do). This filter collects aerosols in the air (more specifically sea salt aerosols). The lab itself is situated upwind and far enough away that the bases air isn't sampled that often (generators, exhausts, dozers). There are a number of other instruments running all the time, so that the scientists back at Cambridge can have a good general picture of what's going on.
Kirsty digging the hole in her 'oil spill suit'. The CASLab is in the back and the 30meter mast to the right.
From the LoVol (Low volume) filters we can see what aerosols were in the air everyday and where the air came from (anemometers). Every two weeks we change a HiVol filter (High Volume) which measures for the same particles, just over a longer time period. All of these filters are sent back to Cambridge at the end of the year (where all of the BAS scientists live) for Ion Chromatography analysis.
The big problem with ice cores is that we don't know how the concentrations of aerosols and gasses found in the ice cores relate to what was actually in the air at a time.
This snowpit sampling links the HiVol and LoVol aerosol concentrations found on the filters to the concentrations of impurities preserved in the snow. This should help improve calibrations of ice core records.
So- now for the fun bit. First of all we had to dig a pit. A big pit. And we couldn't contaminate the snow pack or the composition of the snow, so we couldn't walk on the bit we were about to sample (it's important that no-one has ever walked on it) and we couldn't get chemicals or fuel or even breath on the snow wall!
The big problem with ice cores is that we don't know how the concentrations of aerosols and gasses found in the ice cores relate to what was actually in the air at a time.
This snowpit sampling links the HiVol and LoVol aerosol concentrations found on the filters to the concentrations of impurities preserved in the snow. This should help improve calibrations of ice core records.
So- now for the fun bit. First of all we had to dig a pit. A big pit. And we couldn't contaminate the snow pack or the composition of the snow, so we couldn't walk on the bit we were about to sample (it's important that no-one has ever walked on it) and we couldn't get chemicals or fuel or even breath on the snow wall!
Digging finished!!! Me showing that the hole was 1.5m deep. 1m square and on the left are the steps going down.
Kirsty and I in the hole. I'm actually standing on a lot of snow that I'd just pushed in with me running to be in the photo.
The first 20 pots in the snow wall. They're sampled every 2cm.
Once the pots are pushed in and the depths are measured we used clean spatulas to scrape away the snow around the pot, and then (somehow) get the clean untampered snow into the pot and put the untouched lid on.
Kirsty in all her clean outside lab gear in front of the first 20 samples.
We took 60 samples, which is a lot of faffing about with little pots trying to get them in little bags and not touch either the pot or the snow. As well as the yellow oil spill suits, we wore brand new thin gloves, cleaned our boots, wore facemasks and a multitude of various plastic gloves. Lets hope that all worked.
So the whole operation took us the day (getting prepared for it and lots of time spent trying to get warm again). Another one in two months, yay for Science in an Antarctic Context!!