This week at Davis: 23 December 2016
This week we've been busy with a number of projects achieving some great milestones...
Glacial lakes on the Sørsdal Glacier continued
Field work is all about "hurry up and wait". You can plan all you like, but the weather has to play along. In Antarctica, this is made more difficult by the logistics of a sizeable but remote station – your own project, flight or other travel plans aren't likely to be the only ones waiting for the weather. Last week, everything finally did align and there was no more waiting and we had three consecutive days out in the field!
After the required low–light reconnaissance to make sure we were on solid ground once more, our gang of six people - which included two glaciologists, two electronics engineers and two field training officers - is back on the Sørsdal again. This time we land at "Twin Lakes" which are two side–by–side lakes that, from what satellites tell us, form as far up the Sørsdal as there are lakes.
Only there are no lakes here yet at this time of year, just patches of shiny blue ice and strange sinuous ridges cracked open like bread crust in places. Off we go in search of water.
It turns out the lakes go underground for the winter; a couple of hours spent drilling holes reveal lots of water, some in water pockets, some in slushy ice. The strange bread crust ridges even turn out to have air in them! Like any normal lake in this sort of climate, ours freeze in winter only; if the lake bed is also frozen then things work a little differently.
Again, we put a camera tower up along with instruments to measure water pressure (under and above ground), ice and air temperature. We're hoping to see the full lake filling and "whatever happens in winter" cycle with our instruments. Tom and Sue, inbound on the next Basler flight, will hopefully supplement the instruments we have with geophysical measurements of what's deeper under the surface, using radar and seismic instruments.
As if that was not enough of a good thing, we are off to Channel Lake on our third and final outing, a site we've been eyeing curiously for a while now. Satellites from previous years have again made us believe there should a lake there, but the naked eye sees only see a messy ditch in the glacier surface. Not a normal crevasse, this is a saggy dip in the glacier with broken up edges, and chunks of ice poking out at wild angles; a lake that must have drained. Here the field training officers will be in their element, I think, unsure how far we will be able to explore in the name of science (safety first).
The bark of Channel Lake is worse than its bite; the cracks at the edge are not too wide, and also refrozen. We can move around safely to explore the site, make measurements and leave more instruments. Several metres down inside the ditch, we drill more holes, and find more air and water deep underfoot, below a solid metre or more of ice. The lakes here obviously not only store water for quite a while, they also spill it every now and again. In the case of Channel Lake, the refrozen spillage is easy to see a couple of kilometres down-glacier in the form of a shiny, re-frozen surface water covering that stretches further than the lake itself. Hoping we're not here just to shut the stable door with the horse long gone, we leave more instruments to record any possible future re-filling of the lake - an uncertain but tantalising prospect - and head back to station, our own mission accomplished and the project waiting for the arrival of Tom and Sue. Just in time, it turns out: the next morning, we have word that we have to get to Casey in a hurry, to make use of a weather window to get us back to Hobart - and things that are green and smell of something other than the cold - in time for Christmas!
Bivving out in Antarctica
With the weekend looming, some of the more outdoor-minded folk started planning their walks within 'recreational limits'. The sea ice was still open for foot traffic so it made sense that Anchorage and Gardner Islands were high on the priority list. Our friendly field training officer, Gideon, decided to spice things up and kindly offered to babysit a group on an overnight trip to Anchorage Island. A good number of potential 'bivvy baggers' signed up for the adventure but after survival training on the Friday night and some gloomy weather on Saturday, people bailed out like rats on a sinking ship.
So, on a cloudy Saturday evening with a mild wind still persisting, a small band of brothers and one Rachel, commenced the pilgrimage to Anchorage. The plan was to set up camp on the ocean side, blocking Davis station from view and taking in the sea- and ice–scape. Most were still sceptical about the weather on arrival, but like Moses, Gideon parted the cloud letting the sunshine rain down on the sea ice, icebergs and happy hikers alike. The wind even dropped out to nothing and we became becalmed on the surrounding sea ice.
The view was absolutely amazing and in between Trev's story telling, the silence was almost deafening if it were not for the squawking cape petrels nesting on the distant Bluff Island. As always, the mob of Adélies at the base of the island kept us greatly amused. One social misfit spent so long pumping itself up to dive into a tide crack that the surface had refrozen, offering him a rude shock when the plunge was finally taken! A tap dance and some honking followed his traumatic experience reminding everyone present to always check the water before diving in.
Sleep came surprisingly easy for most until the katabatic wind kicked in around 4:30 am. Packing up was quick but not without incident. One member of our party emerged over the rocks chasing an escaping bivvy bag and set of maps. The walk back to station was uneventful and we were rewarded with a scrumptious brunch.
Shortly after returning, some of our party signed up for Bryce's 'Contiki Tour to Gardner Island' where the number of chicks had greatly increased since the weekend before. That however, is a story for someone else to tell.
Let’s start with the basic question everyone asks, “What is Infrasound?”
Infrasound are very low frequency acoustic waves; these waves are below the frequencies audible to the human ear. Infrasound is produced by a variety of natural and man–made sources: exploding volcanoes, earthquakes, meteors, storms and auroras in the natural world; nuclear, mining and large chemical explosions, as well as aircraft and rocket launches in the man–made arena.
The second question that is then asked is, ”So why are we building an infrasound monitoring station in Antarctica?”
The Davis infrasound station will be part of a planned global network of 60 such stations located around the globe to be monitored by the Comprehensive Nuclear–Test–Ban Treaty Organisations International Data Centre located in Vienna, Austria. This site is being installed by Geoscience Australia with assistance of the Australian Antarctic Division as part of Australia's commitment to the international treaty. The primary purpose of these stations is to monitor the earth mainly for atmospheric nuclear explosions, although the data from these stations is also available for both scientific and civil applications.
So that’s the basics. Now, we can move on to what have we actually been doing since arriving down here at Davis. The site for the Davis infrasound station is located a few kilometres from station and will consist of a central building and seven sensor arrays. The main challenge with this build is the need to be able to fly by helicopter all of the required building materials and equipment to site, as there is no overland vehicle access.
After a bit of a slow start to the season, we set up a small base camp to work from out at the building site and commenced digging the footings. Thanks to Danny’s fine work on our little mini excavator (remember everything on site was moved by helicopter) the footings were completed in good time and the holes where prepared for the installation of the pre-cast concrete footings. Once the footings where in place, the pace of the build picked up and the steel frame was lowered into position by our trusty sky hook.
With everything ready for the freezer panels to be erected that would make up the walls and roof of the building, Adon, David, Jean Luc and Ash headed out to site to start putting up the building. Over the period of four days, the building was constructed in almost perfect Davis weather. Special mention must go to the Heli guys for doing all of the heavy lifting of the building materials and the B team of Chris, Mark, Nev and Rhys who came out to give us a hand with lifting the electronics cabinets into the building.
My first week on the Davis seabird team
With just three days’ notice, it was on. My amazing supervisor at Davis, Louise, had managed to move my flight forward and I was leaving for Antarctica to finally join the Davis seabird team. After her extremely helpful assistant, Colin, provided me with my final gear at the Division in Hobart, I was off – Hobart-Wilkins-Woop Woop-Davis, all in one day. It was a struggle to remember to blink and a week later I think I am still having trouble sleeping from excitement.
My first fieldwork, outfitted in my new favourite AAD beanie, involved travelling by helicopter to Hop Island, inhabited in summer by all seven of the target seabird species for my project. I am still having issues blinking. If you ever have the chance, I highly recommend including a flight over a glacier into your daily commute. I also highly recommend commuting by helicopter, in the front seat if possible.
This is my first time working with Antarctic seabird species and handling my first Adélie penguin was probably my most nerve-wracking experience ever. Things can only get better though, and up next was the cape petrel, a beautiful bird that sounds like a kookaburra and also has the most amazing talent of projectile spitting bright orange krill oil at you as soon as you get too close. My first hit was right in the face, on my new favourite beanie, and somehow inside my sunnies and neck warmer.
It’s only been my first week but as far as I’m concerned I’ve already made it as a seabird scientist, I sure smell like one. I’ve also discovered that the smell is hard to get out, even from sunnies.