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Saturday 10 February marked the formal commencement of resupply operations for Mawson Station, as the combination of the vessel's ice-breaking efforts within Horseshoe Harbour yesterday, and further ice-breaking activities using smaller watercraft, resulted in the station's wharf finally being reached and a channel cleared for cargo operations around 1400 Mawson time (2200 Hobart time / AEST). Several station personnel on shore, the watercraft crews and the team on the Aurora's bridge were all simultaneously letting out shouts of joy and relief, as everyone realised we'd now be able to conduct the resupply as planned.
The day had started with a degree of uncertainty, as the localised winds associated with a katabatic airflow from within the continent (stronger winds generated by cold, clear conditions overnight inland flowing towards the sea as the sun rises and warms the sea air along the coast), kicked up to around 30 knots. The vessel continued a steady 'racetrack' pattern in the large bay outside of Kista strait, with the wind whipping up white capped waves and buffeting anyone on the upper decks. The morning had also been clear however, with no sign of the cloud which had quickly covered the area the evening before bringing thick snow showers – so we were quietly confident that it would still turn out to be a reasonable day.
Around 1000, the winds subsided and the vessel entered Kista Strait, quickly discharging the jet barge and an inflatable boat to send into the harbour and continue work to clear remaining ice. The jet barge was loaded with two large containers, each weighing around 4 tonne, to provide it with additional purchase within the water for its powerful jets, and extra weight forward – so that it would hopefully be more capable of sliding onto, then cracking off, segments of ice at the edge. The Aurora's earlier work had also made it possible to deploy a thin line from shore to the watercraft, which was used to good effect towing a further inflatable boat from shore, across the ice and into the harbour. The watercraft team rapidly set up the second IRB and transferred extra crew aboard – who then joined the first boat in clearing the larger ice floes broken off by the barge from the channel. The Aurora Australis also sent in its own large workboat – the 'AA II' – to compliment the efforts of the other watercraft, making light work of the ice floes with its stronger hull and engine.
Once the channel to the wharf was cleared, it took a very short time for the Station and Voyage management teams to confirm with the vessel that cargo operations could commence, and within an hour the first priority containers were delivered ashore. All watercraft personnel, expeditioners and Aurora crew, should be proud of their efforts.
If our success in finally reaching the wharf at Mawson weren't already enough of a reward, then the breath-taking conditions subsequently presented to us by the Antarctic sunset this evening certainly made up for any shortfall in days' satisfaction. With uninterrupted blue skies and wind dropping to around 1 knot, those aboard knew they'd be in for a brilliant spectacle as the sun sank towards. By 2100 the seas were mirror-calm around the Aurora as it again returned to open waters between the Antarctic coast and the pack ice to our North. Cape petrels accompanied the vessel to sea, skipping over the surface in search of a meal, their ornately patterned black, white and grey forms reflected perfectly in the still water below them. When the sun's disc met the continent to our West, it rested atop the ridgeline of one of the few rocky ranges protruding through the ice plateau in the distance.
Crew and expeditioners were out and about on the decks, some with cameras – others just content to stand and watch, as the setting disc of the sun drew in the twilight. Several expeditioners were keenly awaiting the potential arrival of an atmospheric phenomenon associated with the sun around the Southern poles at this time of year, known as the 'green flash'. The author is relying upon a publication by the Australian Bureau of Meteorology for the following explanation of this phenomenon.
The green flash occurs as a result of the refraction of the sun's rays as it sets, passing through the lower layers of the atmosphere. The sun's light, which is actually white – is scattered into various colours by the atmosphere. Most clear evenings, the effect of the atmospheric scattering sees blue, indigo and violet light removed from the visible spectrum, presenting the familiar yellow sunset, with the last colour seen before the sun disappears being green – the 'green flash'. The flash can often be too faint and occurs too quickly for the naked eye closer to the equator, but at Antarctic latitudes in the Austral summer – particularly approaching March, the green flash may be viewed for as long as several minutes.
There was some speculation aboard as to whether the green flash was actually witnessed this evening, but in any case, it made little difference to the author (who is red/green colour-blind!). Once the sun had set behind the nunatak's crest however, it's residual rays backlit in brilliant gold, the long arcing fingers of snow crystals – formed as snow drifts laying against the mountain's flanks were blown by strong winds up and into the sky above its highest peaks. This display momentarily turned our attention away from the other, more subtle transformation, as the receding light turned the ice plateau's bright surface to a cool blue.
Cheers
Mark & Fred
Map
A map showing Australia and Antarctica. The map shows the journey of one voyage that has occured in the season, with each route highlighted in a distinct colour.