More Digging? Seriously? We Have To Dig To Do Research?

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Now some of you may have got the impression that we went to Antarctica to have fun.  I feel the need to point out that we were there as part of a Postgraduate Certificate, so it wasn’t all trips to wastewater plants and atmospheric research sites! (Honestly - who can think of something more fun to do than tour poo-treatment facilities?)  We also did some actual research ourselves – which involved yet more digging…  I’m starting to wonder if we were actually on a secret digging training camp – kind of like a boot camp, but instead of getting up early to run around a field, we got up early to dig snow.

Anyway, I digress.  One of the science projects we did while in the field was looking at snow accumulation at our campsite at Windless Bight.  Why? 
Well, ice shelves are floating extensions of glaciers and ice sheets.  And according to Dupont & Alley, one of the things they do is hold back those glaciers and ice sheets - without ice shelves, a lot more ice would go into the sea and turn to water (which would cause sea level rise, which I’m not particularly keen on sea level rise given I live in a coastal city).  So, I would like the ice shelves to stay right where they are, doing the good work they’re doing.  But what does that have to do with Windless Bight?  Well, Windless Bight is on the biggest ice shelf in Antarctica - the Ross Ice Shelf (in case you’re wondering, it’s the same size as France).     

So, to find out about snow accumulation, we dug 2m snow pits.  That’s right, 2m deep.  I mentioned we were at digging boot camp didn’t I?  Once we’d got down 1m we took measurements every 100mm of snow density, hardness, and temperature.  Then we dug another 1m down, and did measurements for the second half of the pit. Exciting huh?

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If you’re wondering how these things are measured, I have to admit, it’s not very high-tech.  For density we simply filled a cylinder with snow, and then weighed the snow.  Since we knew the volume of the cylinder, we could work out the density (which equals mass/volume for those of you who did high school physics a while ago). 

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Hardness is measured using the extremely non-technical method of seeing what you could stick into the snow.  If you can push your fist in, then the hardness is 1 (i.e. not hard at all).  If that doesn’t work, then you try to push in four fingers, then one finger, then a pencil, and finally a knife (hardness = 5).  If you can’t even get a knife in, then it is automatically a hardness of 6.  The upside of this method is that you don’t need a degree to operate the equipment.  The downsides are that: a) you don’t get to play with cool equipment, and b) your hand gets cold since you keep sticking it in the snow.

Once we’d done all that digging and measuring, you’d think we could take a well-deserved break. But no.  Instead, the hardiest souls in the group banded together, and continued digging one of the pits down to a very respectable 3.8m.  Apparently the record for PCAS is 6m; all I can say is that a lot of people must have loved digging the year that happened!

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Anyway, having done all of these measurements, what did we find out?  After analysing the data at home, I discovered that Windless Bight gets approximately 1m of snow accumulation a year.  I worked this out based on the layers that we observed in the pit – an ice layer corresponded to summer (melted snow froze to become ice), as did a dust layer (exposed soil due to melted snow gets blown around).  That’s a fairly healthy level of snow accumulation, and indeed, research has shown that Windless Bight is an area of high accumulation.  What is less well-known is the rate of ablation (loss of mass).  Losses from the ice shelf can happen through iceberg calving, melting, or sublimation – which nicely brings us back to one of my previous blog posts.  The radar we set up is measuring the thickness of the ice shelf at Windless Bight over a year, gathering data as to what is happening underneath the shelf.  Pretty cool huh?

For the present though, it looks as though the Ross Ice Shelf is here to stay, which is pretty good news.
 
Posted by Karla Smith on Jan 12, 2017 8:22 PM Europe/London

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A Volunteer in Godzone (aka New Zealand)

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There's obviously more than one IET volunteer resident in New Zealand (aka Godzone), but I don't think anyone else is blogging yet, so first in, first served (mwahahahaha).  I volunteer in a variety of roles - currently I'm a committee member of my Local Network (South Island), a member of NZ Forum, and chair of the Communities Committee - Asia Pacific (CC-AP) (which also means I'm a member of the Communities Resourcing Committee (CRC)).
 
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