This week at Casey: 19 October 2018

How is it that the wildlife of Antarctica know the exact day of the year to return to the icy continent?

We were assured by the AAD biologists that 17 October was THE day. I have to say we were a little sceptical, but we did start the countdown to when the penguins would return to us based on 17 Oct.

And… as I write this article… I look out my office window to Reeve Hill, and I can see the snow petrels circling, preparing to re-establish their nests amongst the rocks. In the distance, small black and white penguin-shaped dots are appearing on the sea-ice preparing to make their way to Shirley Island rookery for the summer. At 0730h this morning, the call went out over the radio: ‘penguin sighted!’

Life has returned to us in a rush, right on schedule. Just in time for our departure and the arrival of another Antarctic species, the AAD expeditioner in one week’s time. Perhaps not as well equipped for the harsh environment as the Adélie penguin or the snow petrel, but they will soon adapt and before long be calling Casey home, just as we who are leaving do. 

In other news, we've had an extremely busy week of getting everything finished, wrapped up, and prepared for handover to the incoming team. We’ve been doing a MASSIVE amount of cleaning and packing. All this amongst four days of blizzard.

The station is looking spick-and-span, even if the population is looking a little worse for wear. We’ve well and truly hit the countdown now and with only one Icy News to go, we can almost taste the fresh fruit and veges and feel the warmth of the summer sun on our faces.

This update may be a little short this week, but I must get it lodged so I can head to Shirley Island to see our new arrivals.

I’ll finally be able to use my mid-winter gift, the penguin caller… unless it’s been packed already…

Rebecca (Casey SL)

Sam Jacobs (mechanic at Wilkins) has sent through photos of the interesting weather phenomena seen up at the aerodrome this week.

Halo is the name for a family of optical phenomena produced by sunlight interacting with ice crystals suspended in the atmosphere. Halos can have many forms, ranging from coloured or white rings, to arcs and spots in the sky. Among the best known halo types are the circular halo, properly called the 22° halo, as seen in Sam’s photos.

The 22° halo, often just called ‘halo', appears as a large ring around the Sun or Moon with a radius of about 22° (roughly the width of an outstretched hand at arm’s length).

As a result of the optical properties of the ice crystals involved, no light is reflected towards the inside of the ring, leaving the sky noticeably darker than the sky around it, and giving it the impression of a ‘hole in the sky'.