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I haven't writen to the list since I've started my job in
antarctica, so thought now that the summer throng has left,
I should.
My name is Darryn Schneider, and I'm the wintering physicist
at Casey station, on the Budd Coast, Wilkes Land. (66deg17min S
110deg32minE). The original station was named Wilkes and was
built by the Americans for the IGY, and then soon handed over
to australian administration. In the late 60's a new station
was built on the other side of the bay (Newcomb Bay), called
Casey station (now Old Casey, or 'The Tunnel', becasue of the design).
In the late 80's a new Casey station was built, and that is where
I am. It is on the edge of the Law Ice Dome, which rises to
a little over 1300m about 120km from Casey. Deep ice drilling is
done there over the summer. the Casey coast runs north-south,
law dome to the east. Thus the dominant weather is an easterly
off the dome. Occasionally we get a katabatic from the Vanderford
Glacier to the south.
To make everyone envious, Casey is a beautiful location, with the
Windmill islands along the coast. Behind Casey, there is a steep rise
up to the Plateau, with a moraine line at the top of the gradient.
My donga (room) has a great view over Clark Peninsula to the north,
with a row of grounded bergs, the Peterson bank, in the background.
the sea ice has well and truelly started to form, however is known
to break out, because of the sea current, over winter. The strongest
wind recorded was 157knots, and the temperature extremes being +9.2degC
to -41.0degC. There are 5 field huts in the Casey area where people
can go for jollies (trips away from the station without scientific
purpose).
Halos haven't been as common as expected. The best display being
recently, a 22deg, 46deg, and weak upper tangential arc.
One great evening I was out skiing over sea ice (the 2nd of Jan I think)
to an island. It was about 10pm and a bank of cloud went over and
dropped some snow on us and went to the SW. Soon after the sun dropped
below this cloud and shone up under it, and turned everything
a beautiful red, with a nice little sun pillar. Didn't have
my camera as we had been doing some down hill skiing (with X-counrty
skis) and falling over with my pack is bad enough without
smashing my camera. When we got to the island we climbed a small
peak and watched this beautiful sun lighting up the underneath
of the cloud, and then it started to lightly rain and
there was a bright, full rainbow over casey, at 11.45pm (local midnight
around 12.30).
I have been given hope that halos will improve, from the station log
of Wilkes station in 1960. The OIC (officer in charge) was a great
log keeper and very interested in science and made many comments
on atmospheric opticals. I thought the list might like to hear
some as he describes them very nicely.
Mar 20 1960 (location, S2, 100km inland from Wilkes)
"Rising at 0630 hrs to rouse the camp, Black (OIC) noticed a striking
solar halo upon leaving his tent. It was in the form of a pair of 22deg
parhelia together with a parhelic circle (about 200deg of circumference
sighted). the parhelia were very bright, one appearing to be just as
bright
as the central image of the sun itself. the cinditions of light breeze,
'diamond dust' crytals, and intense cold (circa minus 10degF at the time)
persisted far the early part of the morning and the halo was visible for
a couple of hours."
same day
"A series of most remarkable 'mirages' was sighted as the coats was
appraoched. the characteristic 'looming' of these latitudes was in
sharp evidence as huge glaciers arose out of the sea in front of
the station area. At one time three layers of ice cliffs arose
one upon another. The station reached at 1730hrs."
Apr 27 1960
"Segments of a 22deg solar halo were observed early in the morning.
the segments, showing the spectrum nicely with reds on the inside
and progressing to greens on the outside, were low on the northern
horizon. the cap was clear at the time but there was a considerable
amount of fog/ or sea smoke offshore/ This appeared to drift in,
providing the moisture needed for the development of the ice crystals."
May 22 1960
"The ski-ing party reported sighting a prominent sun-pillar at this
afternoon at 0620Z. the sun was very low on the horizon, just above
a bank of dark clouds. the pillar was so marked that photographs
were taken. It persisted for an hour."
"the met section reports another optical phenomenon on tuesday
last, at 1706320Z (??) when a parhelion became visible on the
northwestern horizon 46deg west of the setting sun. A low bank of
clouds made it impossible to determine whether other manifestations
were present. Reds were prominent in the parhelion towards the sun
and clouds between it and the sun created a spectacular display
for a few minutes"
July 4 1960
"At 1100 hours a beautiful solar jalo was observed to the west, with
two parhelia (22deg) framing the rising/setting sun just above the
horizon. each sundog was brilliantly coloured with rich reds
and oranges, like its parent the sun itself."
July 9 1960
"The day was notable for another series of solar halo phenomena which
appeared with the first light of dawn about 1000hrs local time and
persisted
until sunset ay approx 1400hrs. the phenomenon took the form of rwo 22deg
parhelia coloured orange reed to match the sun, but with a rainbow effect
exhibited. A sun pillar rose vertically above th sun all day, becoming
even
more pronounced at sunset. At the same time an upper tangential arc to the
invisible 22deg halo became visible for a period. the following met
conditions
applied: temperature wet bulb and dry bulb both minus 20.8degF, relative
humidity 74%, cloud consisted of ice fog (mist)from surface to 1000feet,
wind
velocity 7 knots NE."
"The OIC captured some crystall on plastic coated slides and, as expected,
they
proved to be mainly of simple plates and short colums of small dimensions.
these
have been added to the snow crystal clide collection"
I hope everyone found this interesting. I'd love to hear about some of the
places that others observe from and what they see.
Darryn Schneider,
ASP Phyicist,
49th ANARE,
Casey,
Antarctica.
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