February Drifting

The sun has returned and it’s glorious…sun dogs, halos, soft pastel light, and crisp shadows! It’s powerful and beautiful and I catch myself staring at the blinding light. We’re gaining almost 15 min of daylight every day now and it makes our jobs so much easier.

We are down to the last few weeks here – the spring crew is due to arrive at the end of this week! Things were looking good until we got slammed by a few big wind storms this week. We’re nearing springtime and the worst weather of the year. On Thursday we had sustained 35 knot winds and on Saturday they rose to 40-50kn sustained winds with gusts close to 60 knots…it’s hard to walk in that kind of weather and so much snow gets lifted into the air that it’s impossible to see more than a few feet. Temperatures also rise with the wind speed. Yesterday when it was 50 knots out it was -5F. Nice not to have as much frostbite concerns, but it’s sticky and relatively wet. I would take clear, calm, and -80F any day.

The shop surrouned by it’s moat

A drift that formed after just a few hours of 30+kn winds

 

With so much snow being blown around monster snow drifts form. We had just cleaned up after the last good blow when we were hit again. There’s a giant moat around the shop and the Green House is buried to the roof on all but the south side. There’s still a bit of a moat there. The snow grains are tumbled by the wind, breaking into tiny shards and ground down to rounded grains. The wind pushes it through the tiniest hole – around door frames and through invisible cracks in window caulking and gaps around the walls. The building entrances and exits often comprise of two sets of doors – vestibules help to retain heat and also offer some protection against the persistent snow. Caulking and weather seals help, but in the extreme dry and cold they invariably crack and fail. With a little moisture they freeze to the door and rip off the frame. Constant chipping of ice and shoveling of snow wears down the material too – no matter what you do it’s a losing battle.

The vestibule ufll of snow blown in around the main door.

A snow drift inside from a tiny gap in the wall/floor…below an auxiliary heater.

Thankfully the cold means there is very low water content in the snow and the super dry air evaporates any snow that gets into the buildings quite quickly. We don’t need to worry about mildew or mold here.

Even with the storms, this is my favorite time of the year; gorgeous sunrises and sunsets, a few hours of daylight, but still enough darkness at night to see the stars and auroras. We’ve had a few spectacular nights since sunrise…

A half moon and Venus below aurora

Spring time on the ice cap:

Looking North. Photo: Sam via kite

Halos

Auroras may grace the polar skies at night, but the day sometimes brings phenomenal halos and sundogs. It’s hard to describe the intangible beauty of these phenomena – vibrant spots of rainbow on either side of the sun, glowing pillars of light from the sun, a brilliant stream of light encircling the sky parallel to the horizon…a good display is simply awe-inspiring.

In general atmospheric optical phenomenon (sundogs, halos, rainbows) are not uncommon. Frequent halos and sundogs can be seen around the world when ice crystals in the atmosphere reflect and refract light. Infrequent halos are more often seen in polar regions or at high elevations with colder temperatures and more ice in the atmosphere. A common occurrence with halos is “Diamond Dust” which is essentially a ground level ice cloud filling the air with glittering ice crystals.

All photos below were taken by me, click on any of the images to open the full photo with caption.

22deg halo, upper tangental arc, and parhelic circle

22deg halo, 46deg halo, upper tangental arc, circumzenithal arc, and diamond dust

Parhelic circle, 22deg halo, 46deg halo, and upper tangental arc

The different crystal shapes generate different optics, however ice crystals form in hexagonal symmetry, thus while the crystal might be long or short (columnar or plate-like) the internal angles are always the same. Here at Summit the ICECAPS project, housed primarily in the MSF, is researching these crystals and cloud formations to better understand the complex processes involved in these systems.

The following website is a brilliant source of information regarding atmospheric optics and identifying features: www.atoptics.co.uk. An impressive full list of optical phenomenon can be found here: https://wikipedia.org/Atmospheric_optical_phenomena. For more Summit specific photos and information check out the Polar Field Services blog, Field Notes.

Photograph of a good halo display – 22° halo, upper tangent arc, 46° halo, and parhelic circle at Summit Station, Greenland

 

Below are some of my favorite photos of optics that I have witnessed in the Arctic and Antarctic. If only I’d had my wide angle lens in past seasons! Click on images to bring up caption and full picture.

And HDR image of the nearly setting sun at Summit showing sundogs and a lower sun pillar

A vibrant sundog over the Green House (Summit)

22 deg halo around a climber on the 50m tower (Summit)

A simple 22 deg halo over the South Pole cargo berms

Sundogs around the setting sun at Summit

Sundogs, a faint parhelic circle, and vibrant circumzenithal arc above (Summit)

Washed out, but very bright sundogs, a 22 deg halo, parhelic circle, upper tangent arc, 46 deg halo, and possible 120 deg parhelia (WAIS Divide, Antarctica)

 

According to atoptics.co.uk, 120° parhelia are infrequent, but not super rare. They are often faint and short lived however, I have only ever seen them twice. Below is a panorama at Summit showing bright 120° parhelia.

Bright sundogs, 22° halo, and definite rare 120° parhelia! (Summit)

Looking opposite the previous photo – the 120° parhelia can be seen along the parhelic circle (Summit)

Moon halos are not uncommon either, but require a nearly full moon and darkness as well as halo forming conditions.

Moon dogs around the Big House (Summit)

 

Other interesting optical phenomena include the green flash and fogbows. The green flash lasted a few hours at the South Pole Station in 2013 (check out my post from that sunset with more green flash photos here). This photo was taken through a telescope. It’s a bit blurry due to heat waves and light distortion near the horizon, the same process which causes the green flash to be visible. Fog and fogbows are a frequent occurrence at Summit, Greenland.

 Happy belated equinox and sunrise at Pole!