Then we head into the “hangar” to prep the balloon (plastic balloon, in warmer months we use rubber). The balloons are filled with helium and are clipped to a set amount of weight so we know that we will get consistent rise speeds and burst altitudes. Since the plastic balloons don’t expand, most of it left empty so when it get’s to high altitude at low pressure, the helium has space to expand into.

Then after some final preparation of the ozonsonde package which may include some heating elements to keep the pump warm and getting the battery ready, we are ready to launch!

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 atmosphere has four main layers which are the troposphere (the lowest layer in which most weather occurs), the stratosphere, mesosphere, and thermosphere. There is some ozone in the troposphere, but it is a very small amount and is produced by the reaction of pollution and ultraviolet (UV) light. Most of the ozone in the atmosphere is located in the stratosphere, hence the name the “ozone layer”. The ozone layer is important because it filters out some harmful UV radiation. CFCs eventually make it into the stratosphere and mix in with the ozone molecules. The CFCs don’t do their damage until they react with UV radiation which breaks the bond of the chlorine or bromine atom apart from the rest of the CFC molecule. Chlorine and bromine are highly reactive with ozone (a molecule consisting of 3 oxygen atoms) which then breaks the ozone apart becoming a ClO and O2 (regular breathable oxygen). The creation of ozone in the stratosphere is from the interaction of UV radiation with an O2 molecule. It splits the O2 creating two single oxygen atoms which then react with O2 creating O3 (ozone).

Example of the CFC/Ozone destruction cycle from NOAA’s ESRL website

These appear to be processes that could take place all over the world so why is the ozone hole unique to the Antarctic region? There are two main factors that enable a hole in the ozone layer to form over Antarctica: the polar stratospheric vortex and polar stratospheric clouds. Antarctica’s extreme cold temperatures allow for these polar stratospheric clouds to form. The clouds enhance CFC/ozone reaction causing the destruction of ozone to become very effective. The polar stratospheric vortex forms every winter over the Antarctic continent and keeps the air from interacting outside of the vortex. So basically ozone from outside the vortex is unable to flow in and replenish during this time. That is when we see the lowest ozone values. As temperatures warm through the summer, the polar stratospheric vortex begins to break up, polar stratospheric clouds disappear, and the air mixes back into the Antarctic stratosphere replenishing the ozone layer. The filling in of the ozone hole causes a decrease in ozone worldwide which how it becomes a worldwide issue. The ozone hole hasn’t proved to be decreasing yet but the fact that the harmful CFCs look to be working their way out of the atmosphere is encouraging and we look for the hole to begin decreasing in decades to come.

So right now we are at the point where the sun is getting just high enough (still well below the horizon) that its rays are beginning to hit the stratosphere breaking down the CFCs that are up there. At the Atmospheric Research Observatory (ARO) we measure ozone in three different ways. One is with a surface analyzer that gives us a baseline level of tropospheric ozone, and the other two include the Dobson Spectrophotometer and launching ozonesondes which both give us an idea of stratospheric ozone.

Ozone surface analyzers

The Dobson Spectrophotometer. During the winter, observations are only available when the moon is up. Bad weather and poor visibility can hamper opportunities thus making balloon launches extremely important (especially so this winter it seems!).

For most of the year we launch one balloon a week but as the ozone hole forms we start launching two to three times a week. The idea is that we increase the resolution of the data so that we can see the peak of the ozone depletion. The balloons are great because they give us a complete profile of the ozone all the way up to 30-35 kilometers high.

In the winter we launch plastic balloons. The rubber balloons don’t get high enough due to the cold air. (ideally we like to get up to 28-30km).

When there is enough light outside for video, I will take you through an entire launch sequence explaining how we prep the sonde, prep the balloon, launch the balloon and show the software that gives us the profile of the data. We can even compare what a normal “healthy” layer looks like prior to the hole forming to the hole itself.

Part of the Radiation Budget, pulled from the IPCC Fourth Assessment Report. Source: Kiehl and Trenberth (1997).

Carbon dioxide has a carbon cycle much like water has the water cycle. CO2 is emitted and absorbed in numerous ways. Whether it’s a chemical reaction in the atmosphere that changes molecules of CO2 into something else, the combustion of a fossil fuel producing CO2, or the oceans taking in CO2 from the air and depositing it deep under the surface, they all play roles as sources and sinks of atmospheric carbon dioxide.

Figure from ESRL Carbon Cycle Greenhouse Gases Group. The data comes from the Carbon Cycle Network that includes NOAA Baseline Observatories (like the South Pole Observatory) as well as cooperative programs around the world.

The figure above graphically depicts the carbon cycle on an annual basis. The red strip indicates the data that has been gathered over the last 10 years from the South Pole. The waves in the graph are from the seasonal uptake of carbon dioxide by plant life. For example, in the summertime when trees have their leaves, and plant life is not dormant, you see a large dip in CO2 values especially in the northern hemisphere because plants take in CO2 for photosynthesis. Also notice the difference in variation (waviness) of CO2 between the Northern Hemisphere and Southern Hemisphere. This is due to the very large forests in the N. Hemisphere compared to the S. Hemisphere, and the fact that the N. Hemisphere is more populated. Aside from the annual variation, notice the steady rise of CO2.

In previous posts, we’ve looked at some of the instruments at the Atmospheric Research Observatory (ARO) that measure things like solar radiation. At the South Pole, carbon dioxide has been measured for just over 50 years now and there are a few different methods of obtaining a CO2 value.

One of them is using our Portable Sampling Unit (PSU) that looks like a suitcase containing a pump inside. Using the PSU, we walk out into the Clean Air Sector (CAS), turn on the unit, and pump air into glass flasks which are then shipped back to the Earth Systems Research Laboratory in Boulder, CO for analyzing. (I shot a video of the process which can be seen here.)

The second is hooking the same type of glass flask that we use in the PSU to the Through Analyzer. What this does is bottle up a sample using the same sample lines as our third method uses a Non-Dispersive Infrared Detector (NIDR).

The Portable Sampling Unit (PSU). Flask samples with this unit are done once a week. On the first and fifteenth of the month, they are done in conjunction with sampling from the Through Analyzer.

Upper right: The Li-COR Non-Dispersive Infrared Analyzer. Lower Left: A display graphing the voltages recorded over the past four hours. The spikes are the calibration gases measured once every hour.

The NIDR uses an infrared source which is a heated filament that emits infrared radiation around the same wavelength that carbon dioxide likes to absorb (usually around 4.26 µm). This energy travels through two absorption cells, one of which is containing a sample of air from outside, and another that is containing a reference gas from a compressed gas cylinder. A mechanical chopper wheel then alternates between the sample and reference gas measuring the difference in the amount of absorption between the two. Using the difference of the two cells helps negate the problem of changes in temperature and pressure. Changes in pressure and temperature change the density of the sample which would skew the amount of carbon dioxide molecules in the measurement. This is a very useful machine that requires very little maintenance and gives us measurements continuously 24 hours a day, 7 days a week (there is about 15 min of each hour that it measures accurate known amounts of carbon dioxide in other gas cylinders for calibration).

On the right are the three calibration gases and the reference gas.

Here is a comparison of when the winds are in the Clean Air Sector (CAS), and when they are blowing station air towards the Atmospheric Research Observatory (ARO). The this graph is when the winds were from the direction of the station and the graph that follows is when the winds are in the CAS.

As you can see we easily pick up local carbon dioxide when the winds are blowing from the station. Winds at ARO are within the CAS probably greater than 90 or 95 percent of the time which is why it is such a good place to get long term continuous measurements of CO2.

See, scattered throughout the year, there are really cool things that happen. Such as the first time getting off the plane and seeing Antarctica (definitely had some butterflies in the stomach), standing at the South Pole marker the first time, seeing the last plane leave, seeing the sun go down knowing you wouldn’t see it for 6 months, the beautiful polar night skies, and this Friday the mid-winter mark.

Shoveling out a path to ARO (Atmospheric Research Observatory) just after station closing

And there are still some to come like the sun rising, the first plane landing and taking a flight out of here. So there are all these milestones that are exciting which add up. Yeah, the day-to-day is pretty boring here, but the sum of all the milestones make the entire time down here an amazing experience. That’s what helps me anytime I’m feeling a bit homesick or anxious to move on. And that is what I’m going to remember when I leave in 5 months. (Wait, why am I talking like I’m almost done? Hehe.)

April weather was somewhat significant being the coldest April on record averaging -80.7F which was lower by 0.2F than the previous record set in 1998 (records began in 1957). On top of that, we set the second earliest mark in reaching -100F ever recorded dipping to -100.7F on April 13th. It’s only typical that as soon as April ended, we are on a streak of warm and unsettled weather. For instance, temperatures today are supposed to rise into the -30s Fahrenheit. It’s amazing to me that you can have a range of about -65 degrees without any daily help from the sun. If things keep up, which they look like they will for the near future, we are on pace for the warmest May ever! I wonder what is in store for the rest of the winter?

Taking in the sky from the Atmospheric Research Observatory

The station atmosphere was much quieter however. We only really had only one major event which was a glycol leak in the power plant. The power plant uses a 60/40 glycol to water ratio to cool the diesel generators. The waste heat from the generators transferred to the glycol mix is then run throughout the station to heat the building. My knowledge of how the whole system works is very limited but as I understand it, a thermostat broke open and created a geyser of glycol. It then landed on some of the exhaust manifolds causing it to vaporize and create a huge cloud in the power plant. This triggered the fire alarm. Luckily it wasn’t one of the loops that carry the bulk of the glycol or it could have been a much worse mess. Over the summer, we had so many false alarms that you kind of become desensitized to it always thinking it’s a false alarm. But when you hear the automated alarm system say that smoke was detected in the power plant, and that it’s not a drill, it really gets the adrenaline pumping. As you can imagine, the power plant is one of the locations on station where you could have things really go wrong.

Everyone on station is assigned to an emergency response team and mine is the fire team. Because we are on are own down here, it is our responsibility to deal with these situations. The fire team had some firefighting training back in Denver before we came down Antarctica and we also try to do some training on our own once a week to keep methods fresh. But we are by no means professionals. Needless to say, I was very relieved to find that the power plant was not engulfed in flames and nobody was injured in the incident. The heart rate definitely jumped initially with the thought that I might actually have to go in and drag someone out of a flaming building. We don’t have fire hoses so all we have are fire extinguishers to use on station (there are fixed water and CO2 suppression systems at various locations however). With all the luxuries that the station has, it’s easy to slip into a false sense of security. These types of incidents are reminders that we are still in a dangerous environment.

There are not any traces of the sun on the horizon any more. When the moon is out, it is like a floodlight on the South Pole. It’s amazing how bright it is. It sure makes walking to the observatory every day much easier. Now the moon has gone below the horizon and it’s extremely dark but the stars are incredible. Yesterday walking back from the Atmospheric Research Observatory (ARO), I was lucky enough to see an iridium flare coupled with a really nice aurora. An iridium flare is when the solar panels of a satellite are at just the right angle that it reflects the sun’s light at you. It does it for just a few seconds as it passes overhead. Unfortunately I did not have my camera ready for a photo.

Well that about does it for the update. Seven months down, six to go!

Part of the Radiation Budget, pulled from the IPCC Fourth Assessment Report. Source: Kiehl and Trenberth (1997).

Aerosols have different properties depending on what they are made of. Some of those properties that are important are roughness, color, and size. These properties affect what happens to solar radiation as it reacts with the particle such as whether it will scatter or absorb. For example, a particle of black carbon (left over after burning of a fossil fuel let’s say) is going to be much more effective at absorbing solar radiation than a piece of salt that has a much lighter color as well as a shinier surface (shiner, brighter surfaces reflect radiation better). It is also important how they are distributed spatially around the globe and how long they stay in the atmosphere. To think more about the spatial distribution, at the South Pole, we have no vegetation, dirt, salt water, or large sources of combustion anywhere close to us (aside from our own station which is downwind from where we sample). We have extremely low concentrations of aerosols in the air here compared to a sand desert or near a volcanic eruption. The time that they spend in the atmosphere can depend on many things. If it is a large particle, it may settle back to the surface quicker. If it rains, the aerosol may get collected by the raindrops and land back on the surface. Depending on the hygroscopic (the ability for a surface to become wetted or have water stick to it) properties of the aerosol, water can also condense on them to make cloud droplets.

Speaking of cloud droplets, aerosols can indirectly affect solar radiation by being an ingredient for clouds to form. Water likes particular sizes and types of aerosols to condense upon. The name this particular type are Cloud Condensation Nuclei. If there are no Cloud Condensation Nuclei present, the water has nothing to condense onto and there will be no cloud. The size and type of aerosol affect the physical properties of the cloud as well. Therefore a change of aerosols in a region can change the type of cloud, thus changing its radiative properties. This dependency on Condensation Nuclei brings up yet another complicated variable that can affect the radiation budget.

So that explains a little bit why we are so interested about the “dust” in the air. Aerosols have a significant influence on climate processes. Now let’s take a look at the instruments that deal with aerosols at the South Pole.

The Condensation Nucleus Counter (CNC) does basically what its name says. It uses butyl alcohol to create a cloud by cooling the flow of the air through the instrument. Inside is a particle counter that counts how many droplets there are.

The Nephelometer measures the radiation scattering ability of the aerosols. By running air through the instrument and shining a light through the air, we can detect how much of that light is getting scattered with a photomultiplier tube (PMT). There are filters in front of the PMT in order to detect several specific wavelengths of light. If we know the output of light initially, and subtract what is detected, then we know how much light is scattered by the aerosols.

The Aethalometer is an instrument that we use to measure radiation absorbing aerosols. For this instrument, air is passed through a filter where the aerosols will deposit onto. The filter is illuminated by a lamp and there are two photocells that sense the light. One is a reference sensor on a spot of the filter with no aerosols, and the other is sensing where the aerosols where deposited. The difference between these 2 sensors is the amount of light absorbed.

Here I am using the Pollack which is an older instrument that is used to compare to the CNC. It creates a cloud by depressurizing a chamber which causes the air to cool and form a cloud. There is a PMT that detects light and I watch an ammeter to see how much the current goes down when the cloud forms.

Not pictured is the Water-Based Condensation Particle Counter which is very similar to the Condensation Nuclei Counter that is shown above. The laser inside broke during the summer and we were not able to send it to the lab, get it fixed, and get it back to the Pole before station closing.

So that is how we measure aerosol concentrations and their scattering/absorbing properties at the South Pole. The next process that we measure at the South Pole will be the Carbon Cycle and Greenhouse Gas (CCGG) group. We’ll take a look at the CO2 analyzer and the role that greenhouse gases play in the climate.

Amundsen-Scott Station at Sunset.

Soon we will begin covering up all the windows on station and other buildings. At the South Pole, there is a Dark Sector where there is extremely light sensitive equipment and can be affected by any stray light coming though windows from the station. Not to mention it is a distraction from the beautiful night skies (or so I hear from winter-over veterans). We also have the flaglines that mark the path out to any of the outlying science buildings set up. They will come in handy when visibility is poor in the dark of winter. It is still in the dusk stage right now so we aren’t seeing any stars or auroras yet. Apparently by the second week in April is when it gets dark enough. I can’t wait to take some pictures! Camera batteries last only 5-10 minutes when it gets really cold and windy here so I’m going to have to make some kind of insulated housing for it pretty soon.

Sunset plus two days from the Atmospheric Research Observatory.

We’ve now fired up the TV series Battlestar Galactica (on Blu-Ray HD!). I had heard good things about it so I bought it last summer (northern hemisphere) thinking I could use a good TV series to get into for the winter. So far it’s keeping us entertained. I do a Thursday showing of three episodes every week to try to make it last through the winter. It’s tough to stop at three! Most of the weeks lately have involved me lifting weights before dinner, and then either playing volleyball, video games, watching Battlestar, or some other TV show/movie. Things are quite routine around here.

We’ve had a lot of windy conditions lately resulting in large drifts right smack in front of the stairs up to the Atmospheric Research Observatory (ARO). I’m sure we’ll be fighting these all winter as they get worse. ARO was built so that it could be raised as the snow drifts build up. It is in major need of being either raised or dug out completely. Hopefully this gets done next summer. It looks like it will be somewhat of a project because all of our instrument and inlet lines heading out in different directions and will have to be dealt with. Hopefully it’s with minimal downtime for the instruments. The wind has also carved out a lot of sastrugi that are wave like features on the surface of the snow. We use to have a nice waking path from the station to ARO but now it’s bumpy. Once it gets pitch dark, I’m sure I’ll be tripping and falling all the time on my walks to and from ARO. I already did just the other day!

Just the other day, we had the cold weather phenomenon of yukimarimos form on the surface. They would all collect in the pits of drifts and sastrugi creating a cluster of little cotton like balls of ice. They are very strange. They almost remind me of the seeds that come from cottonwood trees that drift around.

Yukimarimos piling up on a snow drift.

A close-up of the Yukimarimos.