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.

All 4 of our Aerosonde unmanned aerial vehicles (UAVs) survived the trip to Antarctica, and have been setup and test run on the loading dock of the lab.

Dave working on one of the Aerosondes in Crary lab.

The Aerosondes are relatively small, with a 9 foot wingspan. Despite their small size they are capable of flying through strong winds (they were designed to fly through hurricanes), which is good as we expect to see close to hurricane strength winds at Terra Nova Bay, where we’ll be conducting our science flights.

The temperature has remained below 0 F since we’ve arrived. The warmest temperature has been -4 F and the coldest, in McMurdo, has been -36 F yesterday. The past few days have been both cold and windy.

This video was taken from the Crary lab loading dock on Sunday morning. The temperature was -30 F and the wind was blowing 30 mph.

Sunday was particularly cold and windy, with wind chill temperatures down to near -70 F. Despite the cold weather myself, Nick, Peter, and Paul took a walk to Scott’s Hut, located just north of McMurdo. The hut was built as part of Sir Robert Falcon Scott’s Antarctic expedition in 1902. We’re hoping to get a tour of the hut tomorrow afternoon, as no unescorted groups are allowed to enter the hut to ensure that the historic artifacts are not disturbed.

A clear contrast between the old and the new – Scott’s Hut and McMurdo Station.

Nick, Peter, and Paul bundled up for our walk to Scott’s Hut.

While the weather is one aspect of coming to Antarctica at this time of year that I’ve really enjoyed on this trip, the other is seeing the transition from the long polar night to the long days of summer. Since we’ve been here the length of daylight is getting noticeably longer. When we arrived last Wednesday sunrise was at 10:53AM and sunset was at 2:59PM. Today sunrise is at 9:41AM and sunset is at 4:08PM, giving us more than 2 hours more daylight now than just a week ago. By September 21st we’ll have 12 hours of daylight. Once the sun rises on 19 October it will not set again until 24 February.

In many ways, everyday life in McMurdo isn’t too different from life back in the US. We live in dorms, that keep us well insulated from the cold. The dorm rooms are setup to accommodate 2 people per room. I’m sharing a room with Dave. There are communal bathrooms on each floor of the dorm, and each dorm has a TV lounge room.

Dorms

Our meals are prepared for us and served in a cafeteria in building 155 (all of the buildings here are referred to by numbers). Meals include breakfast, lunch, and dinner as well as a midnight meal called Mid-Rats for people that work the nightshift.

Nick, Peter, Paul, Jim, and Dave (from left to right) in the cafeteria.

Building 155, which is the location of the cafeteria, some dorm rooms, and a store that sells snack foods, drinks, souvenirs, and essentials like soap and shampoo.

There are two bars (Gallagher’s and Southern Exposure) and a coffee house in McMurdo.

McMurdo Coffee House

Gallagher’s bar

We are able to go to a gym that includes cardio equipment and weights. The only problem I’ve found in going to the gym here is that I find it very difficult to put on my big parka after working out, since I’m usually very hot and sweaty. I’ve taken to walking the 100 yards from the gym to my dorm in just my shorts and T-shirt after a work out. This is fine, even with the temperature down near -30 F, although my T-shirt did freeze stiff during the less than 5 minute walk back to my room the other day. At least the cold weather makes it easy to cool off after a workout.

We spend most of our time in the Crary lab, which contains offices as well as lab space.

Crary lab

Jim, Peter, and Paul working in one of the offices in Crary lab.

Unlike my office at home I have a very nice view from my office down here, which overlooks McMurdo sound (covered with sea ice at this time of year) and the Royal Society Range of the Transantarctic Mountains across the sound.

This afternoon we visited the Berg Field Center food room, to get food to stock our hangar at the Pegasus ice runway.

Berg Field Center food room

The drive from McMurdo to the runway takes about 30 minutes, and if the weather becomes too bad we will need to stay out at Pegasus, rather than risking getting stuck trying to drive back to town. Weather conditions here are classified as conditions 3, 2, or 1. Condition 3 is considered normal weather and there are no restrictions on travel. Condition 2 is defined by stronger winds (48 to 55 knots), a wind chill temperature of -75 to -100 F, or visibility less than 1/4 mile. During condition 2 weather you are required to check out with the firehouse before leaving town. Condition 1 weather is the worst weather, with wind speeds greater than 55 knots, wind chill temperatures less than -100 F, and visibility less than 100 ft (often due to blowing snow). During condition 1 weather you are not allowed outside and off base travel is not permitted. If we happen to be at Pegasus when condition 1 weather occurs we’ll need to stay there until the storm ends. If we are driving between Pegasus and McMurdo and get caught in condition 1 weather we’ll need to stop where we are and wait in the van until the weather improves, since it is too easy to get lost and drive off of the road in whiteout conditions.

Now that the last flight to Antarctica, until the end of September, has been completed, we are now cleared to start setting up at the Pegasus runway. We are planning on going out to Pegasus tomorrow to begin setting up our office space. Our hangar will be a large tent, and is going to be setup by the carpenters later this week. That should be ready for use by the end of the week. Once that is setup we’ll be ready to start our flights. I’ll include some photos of our facilities at Pegasus on my next post.

The weather in Christchurch was beautiful, with sunny skies and warm temperatures with highs in the lower 60s F. This was a bit of a surprise since August is still winter in New Zealand. The explanation for the nice weather is that Christchurch was experiencing a weather phenomenon known as a norwester, which is characterized by strong, warm northwesterly winds. This is similar to the warm Chinook winds we get in Colorado or the warm foehn winds of the European Alps. Regardless of the source of the nice weather I took advantage of it by strolling around Christchurch and walking through the city’s beautiful botanic gardens.

Trees in the Christchurch botanic gardens. Green plants are something I won’t see again until I return to New Zealand in early October.

I also went up to the Port Hills, the remnants of volcanic activity in this region, which provided a beautiful vantage point to watch the sunset over Christchurch, the Canterbury plains, and the Southern Alps.

Sunset over Christchurch, the Canterbury plains, and the Southern Alps from the Port Hills just outside of Christchurch.

Of course, my time in Christchurch wasn’t all play – I also went to the United States Antarctic Program (USAP) clothing distribution center (CDC) to get my extreme cold weather (ECW) gear for the trip south. USAP participants are given all of the cold weather gear they’ll need to stay warm and safe while in Antarctica. When trying this gear on in a more temperate location like Christchurch it is easy to think that it is overkill, but I certainly appreciated it when I stepped off of the plane in Antarctica to a temperature of -45 F (although I’m getting slightly ahead of myself).

The flight to Antarctica needs to be timed to coincide with the relatively short daylight hours at this time of year, and so needs to land around noon. This means leaving Christchurch around 7AM, which requires a middle of the night wake-up to get to the CDC, conveniently located next to the Christchurch airport, to get into our cold weather gear and check in for the flight. On the day that we flew to Antarctica (Wednesday 26 August) I got up at 2:30 AM to catch the shuttle to the airport. By 4:30AM I’d changed into my cold weather gear, which included insulated socks and giant white bunny boots, long underwear, pants, and an outer pair of windproof pants, a long underwear top, a fleece jacket, and a giant red parka, glove liners and gloves, a balaclava, fleece hat, and goggles. We boarded the plane, a US Air Force reserve C17 around 6AM and were in the air heading south just before 7AM.

Me on the C17 waiting for take-off from Christchurch. I’ve taken off some of my cold weather gear off for the flight.

There is no mistaking this plane for a commercial aircraft, as the inside looks like the inside of a giant warehouse. A pallet of airline seats is loaded in the cargo area, that provides seating for about half of the passengers, with the remaining passengers sitting on nylon webbing seats that fold down from the walls of the airplane. The airline seats have the advantage of being more comfortable, but with less legroom, while the seats along the walls of the plane are less comfortable, but provide lots of legroom. Given all of the padding from our clothes, I find the less comfortable seats with more legroom to be preferable.

Video 1. A view of the inside of the C17 during the flight down to Antarctica. The engine noise you hear on the video is loud enough that it makes talking with other passengers difficult and requires that you use ear plugs for most of the flight.

The flight from Christchurch to the Pegasus ice runway in Antarctica takes about 5 hours. On our final approach the pilot announced that the current weather at Pegasus was -45 F. I’m a bit of a cold weather junky, so hearing this got me excited, as this is the coldest temperature I’ve ever experienced. With temperatures like this it is nice to have all of the ECW gear that seemed like overkill when in Christchurch.

One of the passengers on the flight just before getting off of the plane in Antarctica.

C17 at Pegasus ice runway.

Newly arrived USAP participants waiting to be driven from the Pegasus ice runway to McMurdo Station.

Even though this is my 9th trip to Antarctica it was my first trip that wasn’t during the height of the Antarctic summer (December and January) and I was excited to experience late Antarctic winter, with cold temperatures, strong winds, and dark (during the summer the sun is up 24 hours, so despite having spent many months in the Antarctic previously this was the first time I’d see the sun set and have a dark night). The low sun angle when we got off of the plane cast the familiar landscape of Ross Island, Black and White Islands, and the Transantarctic Mountains in a new light for me.

Ross Island from Pegasus ice runway. This photo was taken near noon, yet the sun was low in the sky.

After arriving in McMurdo we went to the mandatory in-brief that gets all new arrivals up to speed on the basics of life in McMurdo. After that we were assigned dorm rooms and picked up our luggage from the flight. The rest of the afternoon was spent getting settled into our lab space in the Crary lab.

By dinnertime it was already dark out, with a glow of orange along the northwest horizon. By the time dinner ended it was completely dark out, and I saw the stars from Antarctica for the first time.

Our first full day in McMurdo (Thursday 27 August) was spent at more meetings and training sessions, as well as getting our lab space setup and all of our gear unpacked. This will continue for the next few days. While we are getting all of our gear setup the last flights to Antarctica, until the end of September, are scheduled to arrive. Once the last flight arrives we will begin setting up our unmanned aerial vehicle (UAV) launch facilities at the Pegasus ice runway. We’re hoping to make our first UAV flight sometime early next week.

By analyzing the iceberg’s position with respect to the ship we can relate the nearby ocean properties to the presence and the distance of the iceberg. For that purpose, Steve Etchemendy and Kim Reisenbichler from the Monterey Bay Aquarium Research Institute (MBARI) have modified a remote-controlled airplane to carry a Geographical Positioning System unit for marking icebergs.

A flat, tabular iceberg in the Southern Ocean last year.

The GPS units are being delivered within a plastic football dropped on top of the iceberg during flight. On the first try, the plane took some video of the top of the iceberg. Steve and Kim need to wait for good weather (clear skies and winds less than 10 nautical miles per hour) to test and use the GPS-delivery system.

MBARI’s remote control plane with a GPS enclosed in the orange football.

We arrived to a new study area this morning. The winds died down last night from 20 to 2 knots, making the weather ideal to fly the remote controlled plane. As we had finished working with SS-1, we left this morning after breakfast and arrived to Iceberg A43k at mid-morning.

The new location is about 20 miles South of SS-1. A43k is a large iceberg. It is taking more than 6 hours at 12 nautical miles per hour to navigate around it. Our best estimate of the iceberg’s size is 16 nautical miles long and 8 nautical miles wide. We will know the exact size once we finish the circumnavigation.

The plane had a successful mission dropping the GPS unit on top of the iceberg. We are receiving the iceberg position via satellite every 6 hours. In addition to the ship’s radar, the GPS will greatly help our ability to pinpoint the iceberg’s position (latitude and longitude).

Iceberg A34K.