Ice and Medicine at the end of the earth

Archive for December, 2010

Trouble at the Airport

As US airports across the country dig out from massive snowstorms and attempt to catch up from the cancelled flights over the holiday weekend, we at McMurdo are having our own runway troubles.  There are numerous intracontinental flights per day and at least three intercontinental flights from Christchurch, NZ every week that land at the annual sea ice runway, Pegasus runway or Willy’s Field Runway depending on the plane and time of year.   Unfortunately, without a safe runway on which to land the C-17 military jet, T.J. will be spending New Years in Christchurch. 

As ironic as it sounds, most of the runway issues arise from too warm of temperatures here at McMurdo.  With the summer solstice recently behind us, the sun is at its most intense and the warm weather has caused the snow to “sink.”  The last C-17 to take off from McMurdo left a hole in the runway.  Because the runway is made of snow and ice, it takes a lot of people, time and good cold weather conditions to fix this.  It then needs to be inspected to ensure that it is safe for planes to land.  The next scheduled departure time from Christchurch is Sunday night at 11 PM.  This will allow for a colder weather landing at 4AM on Monday morning.  The plan is to do night landings and take offs until the weather cools.

Until now, I did not pay much attention to the fact that the runways are made of ice and require constant monitoring and adjustments for safe landings.  I have been unsuccessful in finding a lot of information about the current runways, but I have pieced together some interesting facts. 

Pegasus Field is on Ross Ice Shelf approximately 15 miles from McMurdo and is the current “airport” in use.  It is located in an area with little snow accumulation.  This creates a firm runway on ice that allows wheeled planes to land, like the C-17 military jet that T.J. is scheduled to arrive on.  The C-17s are flown out of McCord Air Force Base in Washington.  According to the USAP website, Pegasus sits on approximately 110 feet of ice with compacted snow on top creating a white ice runway. 

Willy Field is located in an area with more snow accumulation.  It sits on 25 feet of compacted snow and 250 feet of ice.  It is a softer runway and was previously used as a “skiway” for the ski-equipped aircraft.  Rather than being made of ice, it is made of groomed snow.  I believe that Willy’s field is now more of a backup runway and all flights are landing and leaving from pegasus. I think there are two different runways at Pegasus – one for the ski-equipped planes and one for the wheeled planes.  Interestingly, Willy’s field has been moved three times since its construction because it is in a slow slide toward the sea (that is according to Wikipedia).  The ski equipped planes are flown by the New York Air National Guard.  They support Greenland research when not in Antarctica.

And the final runway in use during the early season is the seasonal ice runway.  This is the runway I have used for all of my flights.  It is on the seasonal ice, so can only be used early in the season.  It is closer to McMurdo making it more convenient for the runway crew and passengers.

As you can imagine, runways on ice and snow create some unique challenges.  One of the jobs of the firefighters is to keep the runway clear.  This occasionally means encouraging a curious penguin or lazy seal to move out of the way of an incoming aircraft.  Firefighters do have to request permission to approach the animals.  

Sometimes the penguins are stubborn.  Check out the video of a firefighter and stubborn penguin taken earlier this year (not by me):

This video has been shortened from its original length of almost four minutes!  If you want to see the original, let me know.

Happy New Years!!


BLAST Off

Happy Holidays!  We had a great holiday weekend here in McMurdo!

Sorry for the lack of posts over the past week. It was a busy week in clinic coordinating field camp medical kits.  But I still had time to watch a large NASA balloon float over town and listen to some science lectures. 

I went to a lecture on a NASA balloon project called BLAST (Balloon-borne Large Aperture Submillimeter Telescope).  I am fascinated by the ability of NASA to see “starburst” galaxies 7-10 billion light years away with a balloon carrying a very heavy “payload.”  BLAST is comprised of two mirrors and heat sensitive detectors suspended from a high altitude balloon above 97% of the earth’s atmosphere.  This allows the scientists to measure the temperature of each galaxy and interpret the rate of star formation.  According to their website, BLAST identified 10 times the total number of submillimeter Starburst Galaxies in one 11 day flight than decades of ground research.  I then watched a documentary film on the 2006 launch of the initial BLAST balloon.  I highly recommend the movie.  Information on the movie and the project can be found at http://blastexperiment.info/index.php

The following photos of the balloon and BLAST are taken from the above website:

Needless to say, after watching the science lecture and BLAST movie, I had to see the launch of BLAST-Pol (the newest addition).  Unfortunately the launches of the large balloons are not advertised around base because they are deemed unsafe for spectators.  I thought I had my sources and even spent one morning walking up toward Scott base with Adam in anticipation of a launch.   I had multiple phone calls on December 20 telling me that the balloon had launched.  I excitedly thought it was BLAST.  I have since found out that BLAST launched yesterday.  Now, all of my excitement over the BLAST launch should go toward the correct NASA balloon, CREAM.

The Cosmic Ray Energetics And Mass (CREAM) Experiment was constructed to measure cosmic rays during ultra long duration balloon flights.  They have had five successful flights, and launched their sixth, CREAM-VI on December 20th.  The balloon floats at an altitude of 38-40 Km investigating high-energy cosmic-ray particles that originated from distant supernovae explosions in the Milky Way.  You can find more about the science of CREAM at http://cosmicray.umd.edu/cream/

Antarctica is a great place to launch Long Duration Balloons because of it 24 hours of sunlight and predictable wind patterns.  “A nearly circular pattern of gentle east-to-west winds that lasts for a few weeks allows the recovery of a balloon from roughly the same geographic location from which it was launched and permits a flight path that is almost entirely above land.”

So, on December 20, we watched the light weight polyethylene film balloon that gets as big as a football field, carries up to 6,000 pounds, and can reach an elevation 25 miles float peacefully over McMurdo.   Kressley (Dentist), Adam (Flight Surgeon) and I watched and photographed the balloon from the deck of the clinic with our telephoto lens cameras. 

You can follow the flight path and data on the CREAM website.  Unfortunately, it appears that the balloon has stopped on the opposite side of the continent.  It is currently sitting at approximately 7000 feet.  I have been unable to find out if this is the planned resting point, if there was equipment malfunction or if the rotating winds did not cooperate.  The map of the flight path is below:

I will update you on CREAM and BLAST as I know more.  In other exciting news — T.J. should arrive at McMurdo on Thursday December 30th (US Wednesday)!!  I am excited to see him and spend New Years together.


Why snow is white but glacier ice is blue

Thanks for all who responded. There were many great explanations!

Below, is mine, but first, I wanted to announce the winners:

General entry: Dana Roberts

AFSA Block 1: Tim

AFSA Block 2: Jacob

AFSA Block 3: Levi

AFSA Block 5: Rachel

Humor Award: Melanie Parker Berg – “Snow is white because that was the color of Snow White’s face, and ice is blue because blue raspberry is the preferred shaved ice flavor of Antarctic penguins.”

Winners will receive Antarctic Dollars and USAP Patches.  Thanks again for participating!

Q. Why is snow white but glacier ice blue?
A. This question is more complicated than it may first seem.  Snow and glacier ice are both made of ice and air, just in different amounts.  To understand why we see different colors, we’ll first discuss two main concepts.

1. Absorption of Light by Ice – White light is an even mixture of all the wavelengths of visible light (from blue to red).  Light is absorbed as it travels through the ice.  Ice absorbs relatively little visible light (either blue or red), but it still absorbs red light ten times more than blue light.

2. Scattering light back to the surface – Snow is composed of a bunch of ice grains with air in between them.  In glacier ice, those air pockets have been compressed into small bubbles.  When light enters snow or ice, it is scattered whenever it reaches an ice/air interface.  So in snow, there is a lot of air and a lot of opportunity for the light to be scattered.  But in glacier ice, there is less air and fewer opportunities for light to scatter.

Putting these two concepts together: Snow is white because the light that enters the snow is quickly scattered back out.  The light travels through so little ice that almost no light (red or blue) is absorbed.

Glacier Ice is blue because the light that enters the glacier ice travels much farther in the ice than it did in the snow.  This gives the ice time to absorb more red than blue light.  So when the light returns to the surface, it is lacking red light, making it appear blue.

This is a photo from an email of iceberg photos that Deb sent to me.  From how blue the ice is we can get a good estimate of how much air is trapped in the ice.


Climbing Castle Rock

It was gorgeous weather on Monday with warm temperatures and little wind.  Adam, Joel, Colin and I decided to hike castle rock after work.  With 24 hours of daylight there was no pressure from the setting sun.  We grabbed a quick dinner and then set out on the eight mile hike.  The hardest part was the steep hill out of town.  Like all other trails around base, it was marked with flags.  The visibility made the rock look close, but it was still 4 miles away.

You can see castle rock in this photo.  Below it is one of the rescue shelter “apples.”  That is stocked with survival gear, stove and food in case of bad weather.

There are ropes set up along the course to provide an easy way to navigate the trail and rock.

This picture is looking back toward the Royal Society Mountain Range.

The view from the top was spectacular.  You could see for miles.  The sea ice has melted all the way to Cape Evans.  In a prior post, I showed pictures of a frozen Cape E and Scott’s hut.  It looks like Cape Evans is now surrounded by open water, or it will be soon.

Look for three floating icebergs in the center of the picture above.

The photo above is looking back toward town.  You might be able to make out the straight trail in the middle of the picture.  We climbed down and hiked back to McMurdo.  The hike back was less exciting, but continued to provide amazing views.  I will never tire of the scenery!

There are new questions from AFSA about ice, global warming and T.J.’s research.  He is responding to these questions from LA.  We have reversed the order of “Questions Answered” on the right hand side of the home page so that the newest questions and answers are on the top.  Feel free to submit your own questions and we will do our best to answer them.  T.J. should be back on the ice at the end of December to bring us photos of WAIS divide!


Holes in the Ice

In prior posts I have mentioned the seal holes that become a hazard to pedestrians and vehicles on the sea ice.  Folks in field safety are great at marking them with black flags so that we do not fall in!  My mom asked an excellent question.  How do the Weddell seals make the breathing holes in the ice?

I spoke to one of the seal researchers regarding this question since I did not know the full answer.  The seal starts at a thin area or point of weakness in the ice (small hole, crack etc.)   They then open their mouth and use their teeth to ream out the area to make a larger hole.   They have large forward pointing teeth to assist in this process.  Interestingly, tooth wear often leads to death  as the seal is no longer able to hunt or maintain their breathing holes.

Adam and Joel, the current flight surgeon and nurse, were lucky enough to see a weddell seal use its teeth to ream out a ramp in one of the man made ice holes.  The walls were to  high for it to climb out of the water without modification.

WATCH THE VIDEO BELOW!

The seal was eventually successful and able to exit the hole to bask in the sun!

Don’t forget to post your answer to the prior question on blue ice!


Tell us why snow is white but ice is blue

Why is snow white but glacier ice blue? This is a question Jessie has often asked me and we want you to tell us.  So we thought we’d try a little contest.

Challenge: Post a comment with a clear explanation for why snow is white but ice is blue

Reward: Antarctic Shwag

Details: We will a choose winner from each of Claire Lane’s father’s AFSA classes and one from other contributers.

Use any sources you want, but please have the comments be in your own words.

Please post your comments  in the next week, by December 17.

Good luck.  We look forward to reading your comments!


Evolution of the Scott Base Pressure Ridges

I am back at McMurdo Station!  I have spent this week reacclimating to work and McMurdo life.  T.J. remains in California with his dad.  His dad is doing well and returned home yesterday!  He still has a long road ahead, but continues to improve every day.  If all goes well, T.J. will be back on the ice in three weeks!

There has been a lot more snow melt since I left McMurdo.  The streets are dirt and mud rather than snow and ice and the hillsides are losing their snow.  The ice runway is making the big move from the sea ice in front of McMurdo base to Pegasus runway on the shelf ice (closer to Scott base). 

In order to see snow and ice again, I joined a tour of the pressure ridges yesterday evening.  You can see photos of a prior hike through the pressure ridges in an earlier post.   Compared to the earlier hike, we had clearer conditions, with bright sun, blue skies and very little wind.  It was a gorgeous hike through a changing sculpture garden of ice.   As you can imagine, the trail has changed a lot since I last passed through.  The ridges are larger and more dramatic. 

I hope you enjoyed the photos!  I still cannot believe the spectrum of blue in ice.  And how it is always changing with the angle of the sun.   I will continue to post my adventures.  And T.J. will start his blog posts when he arrives.  If you are interested in learning more about Antarctica and McMurdo life, don’t forget to check out the “Questions Answered” section of this site.  You can find all of the questions listed on the right hand side of the blog below the archives section.  It has a long list of excellent questions submitted by AFSA students in Minnesota.  Fun to write, and hopefully fun to read!