Aerosonde on launch vehicle at Pegasus ice runway.

We’ve had a very successful field season. We flew a total of 16 Aerosonde flights, 8 of which were “science” flights to the Terra Nova Bay polynya we are studying. We logged a bit more than 130 flight hours and flew a total of almost 7000 miles (too bad I can’t count those towards my frequent flyer miles).

Aerosonde in flight over Pegasus ice runway.

The weather we’ve observed at Terra Nova Bay has been nothing short of amazing. On yesterday’s flight we flew through hurricane strength winds as strong as 90 mph. The wind was so strong that one of the planes came back with a coating of salt on the wings. We think this salt was from sea spray over the open water in the polynya. This is really quite impressive, since we never flew lower than 300 feet above the surface. I can’t even imagine what it must be like to be in an environment where the temperature is below 0 degrees F, the wind is blowing at hurricane strength, and the air is filled with sea spray hundreds of feet in the air.

Wind whipped water and sea ice in the polynya.

Wind whipped water and sea ice in the polynya.

Another observation I was amazed by was a very abrupt increase in wind speed over a very short distance. In the span of just 4 miles we flew from light winds that were blowing at less than 10 miles per hour to winds raging at more than 70 mph. To be honest I was worried for our little Aerosondes, but they handled the ferocious winds with no problem. In fact, other than the first plane that crashed two weeks ago we haven’t lost any other planes. This was better then we had expected, as we thought we’d lose anywhere from 2 to 4 of the planes we brought down with us.

The strong winds did present some problems for our planes. The maximum air speed of the planes is about 60 mph, so when we pointed them into winds stronger then that they were actually blown backwards. This made navigating the planes to the places we wanted to go a real challenge. Despite that we managed to collect almost all of the data we had hoped to.

Speaking of planes, we held a contest on the base to name our 4 Aerosondes. The only rule we imposed for the contest was that the names had to be of Antarctic explorers. The winning names were Scott, Mawson, Shackleton, and Bancroft. Scott was named after Robert Falcon Scott, the second man to reach the South Pole. Scott, along with his party died on their return trip from the pole. Appropriately, our one plane that didn’t make it back was named Scott. Mawson was named after Douglas Mawson, an Australian explorer that spent two winters at Cape Denison, one of the windiest places on the planet. Like Terra Nova Bay, Cape Denison is battered by fierce katabatic winds. Mawson’s book on his experiences there was named the “Home of the Blizzard” and is a fantastic story. Shackleton was named after Ernest Shackleton, whose tale of Antarctic survival is one of the truly great Antarctic stories. Finally, Bancroft was named after Ann Bancroft, the woman who led the first all female ski expedition to the South Pole.

Interesting patterns in sea ice.

In the next day or two we’ll finish packing up all of our gear and get ready to return to the much warmer weather of the mid-latitudes. I’m looking forward to seeing my wife and 7 month old daughter soon.

Flight path for our second science flight to Terra Nova Bay. The Pegasus ice runway, where the Aerosondes take-off and land, is at the bottom of the image. Terra Nova Bay is at the top of the image and is approximately 350 km north of Pegasus.

Close-up of the flight path over Terra Nova Bay. The yellow pushpin symbols mark locations where we had the Aerosonde spirals up and down between 150 and 1500 m altitude to measure the vertical structure of the atmosphere.

The purpose of this mission was to observe the low level winds and temperatures in the atmosphere, with the goal of relating these to the processes happening at the surface of the sea ice and ocean. To help us relate the atmospheric processes to the surface processes we took aerial photographs as we flew over Terra Nova Bay. Seeing the surface state will be very useful as we try to understand the meteorological data we’ve collected.

The flight arrived at Terra Nova Bay around sunset, so we didn’t have much time to take aerial photos before it became dark, but the photos we did get are stunning and raise some interesting questions that we’ll be trying to answer as we analyze the data we’ve collected. One of the big questions is how there was almost no open water despite winds blowing offshore at over 50 mph.

The edge of the continent – the Nansen Ice Shelf (left) and Terra Nova Bay with a thin coat of sea ice and maybe just a little bit of open water (right).

All of the aerial photographs shown here were taken from an altitude of 150 m and each image covers a horizontal distance of approximately 150 meters.

All of the photographs were taken on the first leg of the flight (the leftmost blue line) in the flight path shown above.

The violent mixing caused by the strong winds creates some stunning patterns in the sea ice. In this photo thin slivers of sea ice are rafted onto adjacent sea ice in a process known as “finger rafting”.

One of the common features we observed in the aerial photographs was bands of thicker ice (the brighter white ice in the image) oriented in the direction of the wind. In this photo the wind is coming from the top left corner of the image and is blowing at 50 mph. You can also see some areas of thin ice or open water (the darkest areas) where waves are present.

Another surprising feature seen in the photographs was the presence of ocean waves traveling under the sea ice surface as seen in this photograph. Given the very small amount of open water that we observed it is surprising that any waves were generated at all, since waves are created when winds blow across the surface of the water.

Patterns in the sea ice.

You can see areas of open water (or very thin ice) (darkest spots), areas of thin ice (dark grey) and areas of thicker ice (brightest areas) in this image.

We are planning to switch to daytime flights this week, since the days are getting long enough to allow us to launch at first light and fly until dusk and still have 14 or 15 hour missions. Of course the time between sunrise and sunset is just at 12 hours right now, as it is everywhere on Earth on 21 September. What will allow us to fly 14 or 15 hour flights and still take-off and land in daylight is the fact that the length of twilight before sunrise and after sunset is very long here. We’re hoping to get lots more images of the polynya during these daytime flights.

The first obstacle, and the one least in our control, was the weather. The Aerosonde unmanned aerial vehicles (UAVs) have been flown in temperatures as cold as -30 degrees C (-22 deg F), and this was the intended minimum operating temperature for this project. Prior to coming to Antarctica one of the members of my research group, Shelley Knuth, analyzed 14 years of automatic weather station data from a weather station located at the Pegasus runway that we are using for our UAV flights. Based on her analysis the temperature at Pegasus is above -30 degrees C for approximately 50% of the time in September, and is below -40 degrees C (which is also -40 degrees F) only 9% of the time in September on average. Of course the weather for any given month rarely follows the average, and this September has been a colder than average September, with most days up until the past few days having temperatures below -30 degrees C at Pegasus, and many days having temperatures below -40 degrees C. This made our attempts to fly the Aerosondes very difficult.

Me at Pegasus runway when the temperature was -54 deg F. It was much too cold on this day to attempt an Aerosonde flight.

The two problems we have when trying to fly the Aerosondes at cold temperatures are keeping the engine warm in the time between taking it out of the hangar and getting it loaded into its launch cradle and having various parts of the plane break due to the extreme cold.

Peter prepping an Aerosonde in the hangar.

Aerosonde loaded into launch cradle on pickup truck.

Our most difficult cold weather flight of the trip took place on September 10th. This was supposed to be our first “science” flight to Terra Nova Bay, the location of the polynya (area of open water surrounded by sea ice) that is the focus of the project. The temperature at the time of this flight was near -40 degrees F. It took us three attempts to get the Aerosonde loaded into the launch cradle and get the engine started. Between each attempt we needed to bring the Aerosonde back into the hangar and warm the engine by wrapping it in two electric car battery warmers. We eventually had the plane ready to fly, although we were now quickly approaching the end of daylight, as the sun had already set. Despite the difficult conditions we had a successful launch. Just 15 minutes into the flight we received a warning from the flight control computer that the generator had stopped charging the battery on the plane. This is a serious problem, as the battery holds very little charge in the cold conditions, and without the battery the avionics, that control the aircraft, will shutdown causing the plane to crash. The Aerosonde crew quickly turned the plane around and had it fly back to Pegasus as fast as possible. Luckily the battery held out until the plane landed, although the landing was quite difficult given the quickly fading light.

Aerosonde launch after sunset on 10 September, when the temperature was near -40 degrees F.

The second major obstacle we have faced has been aircraft failures. The Aerosondes are designed as semi-disposable aircraft, so it is expected that during a project like ours, we will lose some aircraft to mechanical problems. On our first flight to Terra Nova Bay, on 9 September 2009, the Aerosonde crashed roughly 6.5 hours into the flight, as it was returning from Terra Nova Bay. The apparent cause of the crash was a fuel pump failure, which caused the engine to shutdown. It was very depressing to watch the display on the ground control computer as the plane slowly lost altitude and finally crash landed on the sea ice north of Ross Island.

On our third attempted flight to Terra Nova Bay, on 12 September we had much nicer weather. The temperature at the time of the launch was -26 degrees C (-15 degrees F). The plane took off from Pegasus shortly after 4PM.

Aerosonde launch on 12 September.

About 3 hours into the flight we lost communications with the aircraft. The communications with the plane are done via VHF radio for line of sight flights and by Iridium satellite phone for over the horizon flights, like our Terra Nova Bay flights. The flight path uploaded to the plane is such that if communications are lost for more than a specified amount of time (30 minutes in our case) the plane returns to a designated waypoint. For this mission that waypoint was over the Pegasus runway. 30 minutes after we lost communication with the plane it turned from its original flight path, which would have taken it to Terra Nova Bay, and began the flight back to Pegasus. We were hoping that the communications failure was just an Iridium phone failure and that we’d regain contact with the plane when it returned to radio range. Nick and Paul estimated that the plane would return to radio range between 8:30 and 9PM. These times came and went and we still didn’t have contact with the plane. By 10PM we’d given up hope that the plane was still in the air, and began to wonder if another problem had occurred causing the plane to crash. At 10:30PM we were relieved when we regained radio contact with the plane. The large delay between the expected return of communications and actually regaining communications was likely due to stronger headwinds than anticipated on the return flight and not getting radio contact as far out as we had expected. We were very relieved, to say the least, that the plane was still in the air and under our control again.

At this point we decided to bring the plane back to Pegasus and have it circle the runway until first light the next morning when we could land it safely. The total length of this flight was 17 hours, which to our knowledge is by far the longest UAV flight ever made in Antarctica (the previous longest UAV flights, done by the British Antarctic Survey were only a couple of hours in length).

Aerial photo of the north end of the Pegasus runway taken by the Aerosonde during final approach for landing. The runway angles towards the bottom left edge of the photo. You can see three vehicles that are waiting to recover the Aerosonde after it lands parked on the side of the runway.

Our fourth attempt to fly to Terra Nova Bay was a success. We launched the plane last night (Monday night) at 4:30PM. The temperature at the time of the launch was -31 degrees C (-24 degrees F).

Here’s a video of the Aerosonde launch on Monday 14 September.

We spent all night monitoring this flight. We chose to do an overnight flight because we had planned a flight time of 15 hours, which would allow us 5 or 6 hours over Terra Nova Bay, plus the 9+ hours of transit time to get to and then return from Terra Nova Bay. Since we have a bit less than 12 hours of daylight here right now the only way to do a 15 hour flight, where we take-off and land in daylight, is to take-off in the late afternoon and land early the next morning.

Paul monitoring our Terra Nova Bay Aerosonde flight on the ground control computer in the Crary lab in McMurdo.

Our science objective for this flight was to measure the horizontal and vertical extent of the katabatic winds that blow over Terra Nova Bay, and push sea ice away from the coast creating the polynya. Katabatic winds are cold winds that drain from the interior of the Antarctic ice sheet to the coast. There are several locations around the coast of Antarctica where these katabatic winds are particularly strong, and Terra Nova Bay is one of those locations.

During the 2 days prior to this Aerosonde flight an automatic weather station on the coast of Terra Nova Bay was reporting wind speeds in excess of 70 mph, with gusts well above 110 mph. By the time our Aerosonde arrived at Terra Nova Bay the winds had subsided a little bit, but we still flew through winds up to 65 mph.

The onset of the katabatic winds during our flight was very abrupt, with our plane flying from winds of roughly 10 mph to winds in excess of 45 mph in just over 5 miles of distance. The observations of the katabatic winds that we made last night are the first three dimensional observations of these winds in the winter, when they are most intense. The only other direct observations we have of these winds during the winter are from automatic weather stations, which provide information just a few feet above the ground. The data we collected last night allowed us to accurately map the horizontal and vertical extent of the katabatic winds with a level of detail never achieved previously. We will use the data we collected to verify our theories and computer model predictions of these intense katabatic winds and to study the relationship between the strong katabatic winds and the Terra Nova Bay polynya.

Map of our first successful Terra Nova Bay science flight with the Aerosonde. The background image is a satellite image showing the sea ice extent several hours prior to our flight. The darker area near the top of the map (where the triangular flight path is located) is the Terra Nova Bay polynya.

This flight was a record setting flight in a number of ways.

As far as we know this flight is the southernmost UAV flight ever. The British Antarctic Survey flew a small UAV, similar in size to our Aerosondes, from Halley Station (located at 75.58 degrees south latitude) in 2007. Our flight today was from the Pegasus white ice runway located at 77.96 degrees south latitude.

One of our team members, Jim Maslanik, a co-investigator on this project, recently returned from a research trip to Svalbard, Norway, where his team completed the northernmost UAV flights, which went as far north as 81 degrees north latitude. In the span of 2 months Jim has been involved in UAV flights that spanned 160 degrees of latitude, almost pole to pole.

Another first for our flight today was that it was the first Antarctic UAV flight made during the Antarctic winter (which ends on September 21st). The temperature at launch today was a very wintry -32 degrees C (-25 deg F).

Today’s flight was also the first UAV flight for the United States Antarctic Program (USAP).

Aerosonde on launch vehicle at Pegasus runway (5 September 2009).

Check out these videos to see the Aerosonde in action.

This video below documents the first Aerosonde UAV flight in the Antarctic (7 September 2009). The Aerosonde is launched from the top of a pickup truck once the pickup has reached a speed of 60 mph.

And here, the Aerosonde UAV lands on its belly (it does not have landing gear) on the Pegasus white ice runway.

We heard that sound again two days ago at Cape Royds, having heard it before in January 2005, when a several square kilometer opening appeared in the fast ice just offshore in a matter of hours. The ice was dissolving, or would we call it melting?, and it was happening so fast that you could see it disappearing without even needing your imagination to be going overtime. It’s kind of like putting an ice cube in a cup of boiling tea water to watch it disappear; only here the water is just a degree above freezing. That’s plenty warm as ice goes. In 2005 the fast ice was thinner, so it went from white ice to blue water; this year it was much thicker, so for a couple of weeks it slowly turned darker shades of gray, as it took on more water. Then, fzzzzzzz.

Otherwise, except for this new patch of open water within the ice, called a polynya (a Russian word; without a doubt the Inuits have a name for this, too), there is still fast ice to the horizon as I have described in various of my previous dispatches.

The Swedish icebreaker Oden going south, very slowly, through the ice a few kilometers out in McMurdo Sound, while a polynya begins to form next to Cape Royds.

The south ‘shore’ of the polynya, the day after it initially formed, showing proximity to the Cape Royds penguin colony (tan area on left side of image). The polynya is to the right, beginning to dissolve the gray ice in the center of the image.

In fact, in the Arctic, Inuit villages — and, for that matter, seabird colonies — are located near to polynyas. And, wouldn’t you know, so are penguin colonies, although at the opposite end of the Earth. This is because polynyas allow these predators much easier access to their food. Normally, McMurdo Sound is one big polynya, and the penguins are here at Royds because of it. As I’ve been making the point in previous dispatches, the Royds penguins have been having a hard time of it this season, because their polynya didn’t form, owing to calm winds which allowed the ice to thicken until not even the strongest winds could blow it away. So, they’ve had a very long walk to get food. That is, up until a few weeks ago, when the few remaining penguins still having chicks were provided a large crack to feed in, just 4-5 km north of the colony. Now they’ve got a full-fledged, mini-polynya and all is right in the World!

Well, just like in 2005, within a day of the polynya forming, a couple of minke whales showed up in it! Where they came from, I’m not sure, but they may have followed the Oden into the ice (35 km from the fast ice edge), and then pealed off when a crack that intersected the icebreaker channel allowed them to get to the Cape Royds polynya. Maybe they heard it fizzing! Or the sounds of joyful penguins!

The minke whales, for several hours, cruised around the polynya feeding all the time. They’d submerge for 6-8 min at a time and likely were like big “Hoovers”, i.e. vacuum cleaners. Between dives, they exhaled (i.e. whale “blows”) 4-5 times, clearly audible in the still air from a kilometer away. Within a couple of hours after the whales’ arrival, the penguins’ diet switched from krill to fish. I’d been monitoring it by watching what passes between adult and chick everyday for the past few weeks. Wow! I knew that the whales could do this to the penguins, but I didn’t realize that the whales were so efficient! Not long after the whales left (they’ve not been seen for about 24 hours now) the penguins’ diet switched back to krill. Therefore, this is pretty good evidence for what we call “interference competition”. The whales certainly eat a lot but also their vacuuming causes the krill to try to escape, of course. And what krill do when being pursued, if they can, is to dive deeper and, it seems, deeper than penguins want to go, especially when there are enough fish to be had at shallower depths, though apparently not in a density that in this case would interest a minke looking for easy pickings. If the whales had vacuumed all the krill, when they left, there would be no food for the penguins. As it was, the krill ventured back up into the light (where the phytoplankton occurs that the krill eat), to then be caught by the penguins again. Both whales and penguins go for the easy meal, i.e. that nearest the surface.

Parent feeding its chick. With binoculars, if you get the right angle, usually it is possible to determine whether krill (pink) or fish (gray) is being fed to the chick.

Well, so, you’d think that maybe whales are an annoyance to Adélie penguins. As it turns out, though, minke whales are life savers! Adélie penguins, if given a choice, would always want to have minke whales around, despite the whales’ appetite and despite the best (?) efforts of the Japanese whalers. You see, minke whales — because, like Adélie penguins, they are pack ice denizens — have evolved a very long and sharp “beak”. When you see the whales in areas were the sea is freezing, it becomes quickly obvious why this is a good thing. The whales use their rostrum to break breathing holes in the new ice.

This ice is thick enough that penguins walk over it. With the whales around, though, the penguins can swim between whale breathing holes much faster than walking. In fact, several years ago, when on an icebreaker at the time of ice freeze-up in the Amundsen Sea, one day there were whales and penguins swimming around, and then the next day, with a dramatic drop in temperature and a freeze, there were whale holes but no whales or penguins. Together, they had escaped north far enough to move away from the area of freezing.

A minke whale pushing up through recently frozen sea ice, the ice around it being 4-5 cm thick.

All but one of these penguins found a hole left by a minke whale; the next whale breathing hole is just behind the lone penguin and this flock of penguins is next going to appear in that hole.

These penguins are not walking on frosted glass. They are walking on ice thick enough to support their weight, but not thick enough that a minke whale could not break a hole.

It is good for Adélie penguins to have as many minke whales around as possible. This one, like the pied piper, is making a “channel” through new ice, soon to be followed by a flock (school?) of penguins, who would much rather swim than walk.

Penguins need whales, especially minke whales, as friends.

One IPY-sponsored project that is especially exciting for bringing indigenous knowledge into polar science is Sea Ice Knowledge and Use (SIKU) project: The ice we want our children to know.

A hunter leading the way onto uiguaq (newly formed ice lip extending out from the floe-edge) and testing the ice. Photo courtesy of G. J. Laidler.

The SIKU project is one of several IPY projects aimed at documenting indigenous observations of environmental changes in the polar areas. This initiative brings together anthropologists, human geographers, sea ice and climate scientists, marine and ecosystem biologists from the U.S., Canada, Russia, Greenland, and France in partnership with almost two dozen indigenous communities in Alaska, Arctic Canada, the Russian Chukchi Peninsula, and Greenland in a concentrated effort to document use and knowledge of sea ice in the Arctic.

Qanngut (crystallized frost formations that form on thin ice) up close. Photo courtesy of G. J. Laidler.

Claudio Aporta, Assistant Professor at Carlton University and a researcher on the project, described how Arctic people depend on sea-ice for their persistence. “People are born on the sea ice, they build summer camps to live on the sea ice, they hunt on the sea ice, even kids play on the sea ice,” he said. People regularly cross the sea-ice and recreate trails year after year. It is these pathways, and people’s knowledge of their ice environment, that Aporta and his team are working on documenting. They use this knowledge in creating an atlas and database that Aporta described as “a new conception of map showing all dynamic features.”

Hunters wait at the edge of a polynya (an area of open water surrounded by sea ice) near Cape Dorset, Nunavut, discussing a seal hunt. Current strength and direction is an important consideration, since seal retrieval is made with small boat launched off the ice edge. Photo courtesy of G. J. Laidler.

Local residents, elders, and community experts work together in the SIKU research. Collectively, they record daily sea ice and weather observations, collect local terms for sea ice and weather phenomena, document traditional ecological knowledge related to sea ice and sea ice use from local elders and experienced hunters, and search for historical records of sea ice conditions. Documenting these factors allows the researchers to interpret shifts in ice use patterns that may be caused by social and climate change. Most importantly, “Local people are taking a very active role in documenting their own use of the sea ice,” Aporta said, “ and securing knowledge for future generations.”

Hunters in a retrieval boat launched from the ice edge. Photo courtesy of G. J. Laidler.