This summer Davis has struggled to live up to its moniker ‘The Riviera of the South'. A noticeable chill in the air heralds the coming winter, with just a few of the glorious days that Davis is known for.

The value of darkness

The passage of time brings the oncoming darkness; the 8th of February marked the end of eternal light with the official start of twilight at Davis.

The atmospheric research group runs several experiments in the dark. Most of these focus on the hydroxyl layer in the upper atmosphere. This area of the atmosphere glows very faintly green but also more strongly in the infrared spectrum. By the use of specialist instruments and filters we can observe this glow and determine information about that region of the atmosphere.

A significant experiment is the Czerny Turner Spectrometer which has been measuring the temperature of the hydroxyl layer since 1993. This experiment was disabled during the summer for calibration and improvements and has now started back up.

Another experiment, UWOSCR (University of Western Ontario Scanning Radiometer), was installed in 1998 after spending several years in France. It scans the sky +/- 8 degrees from the zenith recording the light intensity of the hydroxyl layer to record images of the horizontal structure. Due to the sensitivity of the camera it’s covered each summer and only operates after dark.

We also have two CCD camera based systems which are running this year. One is part of the collaboration with the German based IAP (Leibniz-Institute of Atmospheric Physics).

The other in collaboration with Utah State University. Both of these are looking to study gravity waves propagating through the layer.

Our last experiment, the Fabry-Perot Spectrometer, in collaboration with La Trobe University, requires a little more darkness before it can operate.

Barb and the birds

All summer Barb has been busily attaching GPS tracking tags to just about anything that moves, whether it is emperor penguins at Amanda Bay, snow petrels at Filla Island or Adelie penguins at Hop Island. This week, Barb visited Gardner Island to deploy GPS trackers on some Adelie fledglings and returned to Filla and Hop Islands to check on the GPS tags previously deployed. 

The Adelie fledglings, only around six weeks old, are almost ready to head out to sea, with many having already shed much of their down feathers in preparation for the big day. At this point in the season it is common at Adelie colonies to see chicks and fledglings endlessly chasing their parents around begging for a feed. The GPS tags, while small and unobtrusive for the penguins or birds, provide a wealth of information on their foraging habits, giving data on their feeding grounds along with foraging times and durations providing data until they fall off during the next moult.

In addition to the GPS tags, automated camera systems have been deployed at some of the penguin and bird colonies around Davis (as well as the other Australian Antarctic Stations) to monitor them throughout the year. The images from these cameras can then be used to ascertain breeding success and mortality rates for a given colony as well as providing the details of their arrival and departure each year.

Elephant seal science

Not to be outdone, the seal scientists, Dr Clive McMahon (team leader), Bonny Cumming (project veterinarian) and Marine Desprez (PhD student) have also been deploying GPS trackers of their own, this time on some of the elephant seals around station. Having arrived in late January and remaining until V5 at the end of March, they hope to capture and track 25 elephant seals as part of an ongoing study monitoring both seal behaviour and detailed oceanographic data using state-of-the-art SDRL trackers. 

The team preferentially target juvenile seals, weighing between 300 and 500 kgs. Following capture in a canvas head bag, the seals are sedated with an intravenous anaesthetic before morphometric data such as weight, length and girth measurements are taken. Blood, blubber and whisker samples are also collected whilst the SDRL tracker is glued to the seals. The state-of-the-art trackers remain on the seals until the following moult, which usually occurs approximately 9 months after deployment, when they fall off. 

To date the team have successfully deployed six tags and eagerly await the peak haul out (mid March) when the greatest numbers of elephant seals are hauled out on the beaches surrounding Davis station. Another University of Tasmania/Macquarie University team will soon land at Casey to deploy 25 trackers on seals there. 

Sojourn at Law-Racovita

This week a team of four brave adventurers went to the Larsemann Hills to advance the cause of international science, and have a little bit of fun.

Australia maintains Law-Racoviþã station in the larsemann Hills jointly with the Romanian government. It’s not normally occupied, though occasionally visited by expeditioners at the nearby Russian and Chinese stations. We travelled in by helicopter and stayed at Law-Racoviþã for three nights.

On the first evening we visited the Russian base, Progress II, and spent time with Dr Alexandra Frank-Kamenetsky, Director-General Science for the Russian Antarctic Expedition as well as the station leader Victor Vinogzadov.

We were shown their new facilities, just being finished after a fire in 2008 destroyed their living quarters. We were also shown several new scientific instruments being installed such as their magnetometer hut. This had to be custom made with virtually no steel and included hand crafted aluminium heaters and a wooden snow shovel. They have also installed a riometer similar to the one at Davis and we discussed their efforts to develop snow compaction techniques which will allow heavy wheeled aircraft to use Progress’ snow runway.

During the second day we walked the Larsemann Hills. Several years ago one of the apple’s at Law-Racoviþã exploded in the wind and was scattered across the area. It was a while before the wreckage was collected and the wind had broken much of it into small scattered pieces. We found four pieces several kilometers from the station, each about 30cm square, and collected them for proper disposal.

We also climbed the highest peak in the south western corner of Broknes peninsula and discovered that the top of the unnamed hill had a high concentration of red garnet. This was both embedded in the rock and released by weathering to sit on the ground.

On the third day we visited Zhongshan Station, the Chinese presence in the Larsemann Hills. We spent time with the station leader, Dr Desheng Han, also an atmospheric physicist in his former life, atmospheric physicist Dr JianJun Liu and the surveyor Dr Yujun.

Dr Ray Morris, Dr Liu and Dr Han discussed past papers, magnetic shock events, auroral activity and future research directions. In particular they are considering a LIDAR system for one of their stations and we arranged to give a presentation on the Davis LIDAR on our next visit.

Valentine’s Day heart urchins

The fine weather also presented an opportunity for the marine science team (Mel, Cass, Glen and Lucas) to head out on the boats to collect their first batch of heart urchins (Abatus sp.) for the season.

The urchins, which keep their young in brood pouches for up to a year, will be the subject of a series of experiments in the Ecotox aquarium over the remainder of the summer to investigate the impact of ocean acidification and increasing ocean temperatures on the marine life around Antarctica.

Once the juvenile urchins have been collected from the brood pouch of the female urchins, they are raised in the aquarium in water of differing temperatures and pH levels and monitored to gauge the impact of predicted climate change on their development.

LIDAR luminescent again

Over the past week the night sky has returned to Davis, bringing with it the possibility of aurora and noctilucent cloud sightings and the first sighting of stars since before the arrival of V1. Another feature of the Davis night-time skyline made its appearance this week with the Davis LIDAR beaming into the night sky once again. After lots of headaches and countless hours of work over the summer by David “Fluffy” Hosken and Nick “Not-so-fluffy-but-getting-there-slowly” Chang to rebuild and calibrate the laser, the LIDAR is now back online, with only some final tuning and clear skies holding them back. 

The Davis LIDAR uses pulses of LASER light to measure atmospheric properties such as density, temperature, wind velocity and aerosols up to 90km above Davis through the scattering and absorption of the light in the atmosphere, providing valuable insight into long term changes in the polar climate and atmospheric processes.

Cold wet stuff

It seems that February is the time of year when Davis becomes less the Riveria of the South and more the southern English coast. Our beautiful sunny days start to be hidden among grey overcast weather and light snowfalls.

On the upside, we have snow now and the hills of the Vestfold look stunning with a dusting of white.