Geoff Sims @ UNSW
Home South Pole Diaries 2012/13 12th January, 2013


Saturday, 12th January, 2013

Diamond Dust and Carp Party (Geoff)

Today I saw my first "diamond dust" halo around the Sun. It wasn't a particularly amazing one (as far as halo displays go), but it was the best we have seen yet. Unlike halos that occur at temperate (and even tropical) latitudes which are caused by ice crystals in the upper atmosphere (even in the topics, the upper atmosphere is very cold), diamond dust halos are caused by the same ice crystals but at ground level.

In this halo, diamond dust produces a 22-degree halo, parhelia (sun dogs), a faint upper tangent arc, and a circumzenithal arc.

After admiring the halos, we headed to the annual Carp Party, held in the carpenter's work area. It was complete with ice luge, esky and coat rack.

-- Geoff


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