Notice the bit of sunlight on the side of my face!

The main station and sunrise. This photo was actually taken a day before “official” sunrise. In actuality, the sun takes a several days to rise.

On station, we have begun the large list of tasks posted by our station manager which mostly involve shoveling out buildings that have been dormant for the winter, and performing deep cleans of bathrooms, hallways, and work areas. I’ve decided that I have spent enough time inside so I volunteered for a few shoveling tasks namely the cargo office, cargo DNF (the building that houses cargo waiting to be sent out or received that can’t be frozen), and a summer camp Jamesway tent. The FEMC (Facilities Engineering Maintenance and Construction) crew is probably the busiest group with the station opening work as they have to get fuel to all the buildings and start heating them up so they are ready when the summer folks arrive. Our heavy equipment operators are busy as well removing snow and beginning to smooth out the skiway for the first flights. They have had a little bit of trouble due to the cold temperatures because they cannot operate the bulldozers under certain temps.

The BIF (Balloon Inflation Facility) is just below the Sun. To half cylinder shaped buildings to the left are the Jamesways that are being dug out and warmed up for the summer crew.

At ARO, I’m just finishing up inventory to figure out what needs to be shipped down during the summer. It is mostly unchanged from last year because we haven’t had many problems with the instruments this year so there will probably just be a few items to alert people back at ESRL in Boulder, Colorado about. We are also at our intensive ozonesonde launching period where we are launching every 2-3 days as opposed to our normal one per week. It’s been rather unexciting in the depletion department this year. It seems that the polar vortex may not be all that well defined as some years with very low ozone levels. A description of the process of the annual ozone layer destruction over Antarctica can be read in my previous post, “The Ozone Hole: It’s Still There!” Once the sun is a little higher in the sky, we will be able to resume daily measurements with the Dobson Spectrophotometer (measures total column ozone through the atmosphere).

The solar instruments have also been placed back on the roof and are collecting data again. Initially they were having trouble with the -90F temperatures, but we have seemed to iron out the problems and they are now tracking the sun well. For an overview of the solar instruments, see the previous post, “As Sunset Approaches, Let’s Talk Solar Radiation”.

The roof of ARO and various solar instruments.

The next thing that is on tap for myself is organizing all of the flask samples that have been taken over the winter and getting them ready to ship out in the summer. Mostly that just involves writing up the paperwork so it’s ready to go for my replacement (yay paperwork!). Oh, and packing. The thing I look forward to least is also on the agenda. I will need to find boxes to ship home all the things that have kept me entertained here such as my Playstation 3 and movies. As well as excess clothing that I don’t want to travel with.

As I mentioned in “The Ozone Hole: It’s Still There!”, I will be posting an ozonesonde launch with the plastic balloons that we use. Don’t worry, I haven’t forgot! I have it videotaped and will get it posted soon!

Here are some more nice pictures during the last month or so:

The Moon and Venus. The were the last two visible objects in the sky as the sun was closer to coming above the horizon.

ARO from halfway between the station and ARO

The Moon over the Clean Air Sector, directly opposite of the rising Sun.

Nice reflection off the corner of ARO

The Moon about to set out over SPT (South Pole Telescope)

The delay has caused to me think about my time in Antarctica and how much things have changed in the 5 weeks I’ve been here. The weather, which was brutally cold when we first arrived has moderated substantially. During the first couple of weeks of our time in Antarctica we needed to bundle up and cover all exposed bits of skin to face temperatures in the -40s F and wind chills as cold as -90 F.

Waiting on the sea ice to drive from McMurdo to Pegasus. This photo was taken on September 2nd when the temperature was near -30 F with strong winds creating bitter wind chill temperatures and blowing snow. On the next day the temperature dropped to -49 F, which set the all-time record low temperature for McMurdo in September.

Now our high temperatures are around 0 F and it is warm enough that for short walks around the base we can go outside in light fleece jackets without wearing a hat or gloves. It is amazing how quickly the human body adjusts to this harsh environment, since before we arrived in Antarctica I’m certain we all would have thought that a temperature near 0 F was bitterly cold and required bundling up in many layers of clothes.

When we arrived in late August the sun was up for just over 5 hours per day, and was barely peeking above the horizon, with pitch black nights. Today, the sun was up for nearly 15 hours, with the night sky not getting completely dark as the sun skims just below the southern horizon at midnight.

McMurdo at night.

One thing I had been hoping to see on this trip was the Southern Lights. On the night of our first successful Aerosonde flight to Terra Nova Bay I was fortunate enough to step out of the lab for a little while to get some fresh air and noticed the Southern Lights shimmering overhead.

Southern Lights over Black Island and Mt. Discovery. A faint glow from the sun is seen over the southern horizon in this picture taken near midnight.

On my previous trips to Antarctica I’ve never experienced sunrise or sunset, as it had been light 24 hours per day for months on end. I’ve enjoyed watching the sunrise and sunset every day while here for this WinFly trip.

Sunrise over Ross Island.

The cold Antarctic atmosphere is capable of creating some stunning, and sometimes disorienting, optical phenomena. One interesting optical effect we’ve seen quite a bit of is called a fata morgana. A fata morgana only occurs when there is a sharp increase in temperature with height through a thin layer of the atmosphere. When temperature increases with height in the atmosphere it is referred to as an inversion, since this is normally the opposite of what normally occurs in the lower part of the atmosphere. When a very strong inversion exists light reflected from objects on the horizon gets bent, causing objects near the ground to appear to be elevated. In the case of small rocks near the ground, these rocks appear to be large cliffs.

Fata morgana from Pegasus runway. In this photo you can notice distortion near the horizon, at the base of the mountains and also about halfway up the side of the mountains. These areas that appear to be cliffs are actually optical illusions called fata morgana.

The distortion of light as it passes through the atmosphere is not confined to just near the surface. One day while watching the moon pass behind Mt. Discovery I noticed that the moon was not circular in shape, but instead had an irregular outline. The wavy appearance of the moon’s outline was due to differential distortion of the light reflected from the moon as it passed through the atmosphere.

Moon over Mt. Discovery. Note the distortion in the circular shape of the moon. This is most evident on the top left side of the moon in this image.

An atmospheric phenomenon that is unique to the polar regions in winter is polar stratospheric clouds. Almost all clouds that we see in the atmosphere form in the lowest layer of the atmosphere, known as the troposphere, which extends to a height of about 6 miles in the Antarctic. Polar stratospheric clouds form at heights of 9 miles or more, in the layer of the atmosphere known as the stratosphere. Normally no clouds form in the stratosphere due to the dry conditions in this layer of the atmosphere, but at very cold temperatures, what little water does exist can condense to form clouds. Polar stratospheric clouds form at temperatures less than -78 C (-108 F) and are often made up of both frozen water and nitric acid. These clouds are more commonly referred to as nacreous clouds, with the root of the word nacre meaning mother of pearl. The name comes from the stunning mother of pearl coloration of these clouds.

Nacreous clouds from Pegasus ice runway.

Because these clouds are so high in the atmosphere they remain lit by the sun long after the surface and lower clouds have fallen into shadow as the sun sets. This is similar to how the top of a tall building remains lit by the setting sun after the base of the building has already passed into shadow.

Nacreous clouds over Hut Point and McMurdo Sound. The building visible on the horizon is the hut built for Robert Falcon Scott’s first Antarctic expedition at the start of the 20th century.

While I’ve enjoyed this trip to Antarctica more than any of my previous trips, and am very happy with the data we’ve collected I’m hoping that my next blog post will be from New Zealand or back home in Colorado.