Monthly Archives: November 2010

Operation IceBridge Completes Another Successful Antarctic Campaign

Posted on by .

From: Michael Studinger, IceBridge project scientist, Goddard Earth Science and Technology Center at the University of Maryland

A compilation of flight lines shows the paths of all 10 flights flown during Operation IceBridge’s Antarctic 2010 campaign. Credit: Michael Studinger

SANTIAGO, Chile — For the first time in six weeks the nose of the DC-8 is pointing north today after taking off from Punta Arenas airport. Instead of heading south on our familiar flight path to Antarctica over snow capped mountains that soon mark the last land before the windswept Southern Ocean, we are heading north towards Santiago, where we will stay overnight and continue on to Palmdale, California on the next day. We have completed our science flights over Antarctica and are heading home.

We had a very successful campaign and accomplished many things although it was challenging at times. Worse than normal weather over the Antarctic Peninsula and Marie Byrd Land and aircraft downtimes slowed down our progress during the deployment. By adapting our plans to the situation we were able to fly 10 successful missions making use of 84% of the allocated science flight hours. The IceBridge teams have spent 115 hours in the air collecting data and have flown 40,098 nautical miles, almost twice around the Earth. We collected landmark sea ice data sets in the Weddell, Bellingshausen and Amundsen Seas. We have now flown over every ICESat orbit ever flown by completing an arc at 86°S, the inflection point of all ICESat orbits around the South Pole. We have surveyed many glaciers along the Antarctic Peninsula, the Pine Island Glacier area and in Marie Byrd Land. We have collected data along a sea ice transit at the same time ESA’s CryoSat-2 satellite flew overhead allowing us to calibrate and validate the satellite measurements.

IceBridge teams pack the DC-8 in Punta Arenas, Chile, preparing to return home after the mission’s 2010 Antarctic campaign. Credit: Jim Yungel

We are fortunate to have the best equipment and tools for our research. The NASA DC-8 aircraft is ideally suited for our challenging missions in an extreme environment. The science instruments on the aircraft are cutting edge with unique capabilities. But it is the people of IceBridge that make the success of IceBridge, not the instruments or the aircraft. I would like to thank everyone involved in this campaign, at home or in the field, who with their dedication, experience, and skills make IceBridge a success. We also depend on many people and organizations who support our missions. The list is long but the following deserve a special thank you: our Chilean friends from the Centro de Estudios Científicos, the personnel of the Dirección General de Aeronáutica Civil at the Punta Arenas airport, the Armada de Chile, the Universidad de Magallanes, the U.S. Embassy in Santiago, the CryoSat-2 teams from the European Space Agency, the National Science Foundation’s Office of Polar Programs, the British Antarctic Survey, UNAVCO, the AMPS weather forecast team, and last but not least the staff at the hotel Diego de Almagro in Punta Arenas. Thank you all!

We are looking forward to returning to Punta Arenas next year for another IceBridge campaign over Antarctica. Meanwhile check this blog for our upcoming campaign over Greenland and the Arctic Ocean with NASA’s P-3B aircraft in March 2011.

What Could go Wrong?

Posted on by .

From: John Sonntag, OIB Management Team member and ATM Senior Scientist, Wallops Flight Facility

One simple and irrefutable fact of airborne science is that things will go wrong. We utilize complex machines, such as airplanes and unique science equipment, in remote and often austere places, far from help and spare parts. We are heavily dependent on weather forecasts, in parts of the world with relatively little real data to inform the forecast models. These issues inevitably create challenges and problems. Sometimes the bad stuff is minor, sometimes it is crippling, and sometimes it just plain gets to you. For me, the Operation IceBridge Antarctic 2010 deployment had the third effect.

Of the four NASA-operated OIB field programs executed to date (remember that OIB funds two smaller university-operated efforts as well), this one has been the most beset with problems. First, our calibration mission prior to departing was delayed by the discovery of a problem with the DC-8’s rudder trim tab, which had to be replaced. This was no big deal, really, and obviously could not be a harbinger of things to come.

Shortly after we arrived in Punta Arenas last month, several members of our team got a bad stomach bug, or possibly food poisoning. Everyone recovered fully within a few days, but from what I was told it was the sort of stomach problem that makes sudden violent death seem like an attractive option. During and shortly after the gastrointestinal crisis, members of two different instrument teams were involved in (separate) automobile accidents, incredibly enough, at the same intersection. Thankfully everybody was OK, though issues with insurance, local police, and rental car agencies persisted for weeks.

Around the time of the second auto accident, it was also becoming clear that weather had become a major impediment to our operations. We watched a seemingly endless train of weather systems relentlessly pound our primary science targets around Pine Island Bay and the Peninsula, utterly frustrating our hopes to get in there for several weeks. We were able to hit other high-priority science targets, including three important sea ice surveys and a pair of flights around the South Pole, but soon we began to run out of targets other than the areas that were consistently socked in.

Next, that became a moot point when our mechanics discovered a broken fitting in a landing gear door on the DC-8. It took a few days to get the replacement part all the way down to Punta Arenas, and once it got here and the repair was made, well, the weather hadn’t really improved. So we took a chance on a marginal weather Saturday to get more than half of our “Peninsula 23” flight done. That raised spirits considerably, until the next morning when mechanics discovered a failed fuel flow sensor in the #3 engine. Luckily, we had a spare. Unluckily, the spare was also broken. It would take a few days to get another part shipped here.

I hit my personal rock-bottom three days after that, when word came around that there had been a foul-up in the shipping of the replacement fuel-flow sensor and that it was still sitting in a cargo warehouse at LAX. I went for a walk on the beach, looked out at the Strait of Magellan, and found myself idly wondering what people walking nearby might think if they saw a grown man cry, or perhaps throw a tantrum. I also ran across Science Team Lead Seelye Martin, who was out on the beach for the same reason. We exchanged approximately five dejected-sounding words and parted when neither of us could even work up a smile to help buck the other up.

In my 17+ years as an airborne scientist I’ve seen illnesses, scary traffic accidents, and especially, bad weather and broken airplanes adversely affect plenty of field programs. I just can’t recall so many diverse problems afflicting a single deployment as we have seen in this one. And I’ll admit it – the stress and frustration got to me. And I’m pretty sure I wasn’t alone, after seeing lots of long faces in project meetings and around the breakfast room at the hotel. Something else that makes this difficult to take is the inevitable comparison to our remarkable success here in 2009, when we racked up an incredible 21 long-distance science flights. We all went home after that feeling like conquering heroes, even though we knew we’d been lucky with favorable weather and a smoothly-running airplane.

But then, things began to look up. First, word came down that the long-delayed part was on a plane, on its way south out of LAX. We’d have it Thursday evening and could fly Friday. Then, our meteorological analysis showed unmistakable signs that the weather pattern that had bedeviled us for weeks was changing! Pine Island Bay and its surroundings were finally opening up! This was just in time for the part to arrive, and for us to knock out 2-3 flights in quick succession to finish up before we’re due to pack up and be home in time for Thanksgiving.

As it turns out, the fun wasn’t quite over yet. The weather forecasts held up beautifully, but another minor foul-up with customs paperwork delayed the part until the flight due to arrive at 3 am Friday morning. Worse, when it got here it immediately got locked up in another cargo warehouse which refused to open until 9 am Friday, despite the fervent nocturnal pleadings of our maintenance guys waiting nearby. With a few hours needed to make the repair, we decided to delay our takeoff to 3 pm, making for a very long day for everybody but meaning that we’d maximize our chances for a 3-flight run to finish up the project. During the morning while our crew was making the (rather involved) repair out on the open ramp, the nastiest local weather we’ve seen since our arrival blew through, with howling 30-40 knot winds, rain and blowing snow, making their time-pressured work even more difficult and uncomfortable, and making the rest of us fret about cross-winds, snow accumulation on the plane and all the other problems such a squall can create. But by the time they finished the repair, the sun was back out and we were go to launch! We flew a 100% successful evening mission in perfect weather conditions over the Thwaites and Pine Island Glacier basins yesterday, after the nail-biting drama of the overnight and morning, and landed around 2 am.

That was yesterday. As I write this account, it is now Saturday and we are again over Pine Island Glacier enjoying ideal weather. Most of us only had time to sleep 4-5 hours after the late-night landing yesterday and today’s noon takeoff, and there are lots of hollow eyes as well as a styrofoam menagerie of coffee cups strewn about the cabin. Nevertheless this is now a happy and fiercely determined team. We are now engaged in a full-bore, all-out sprint to the finish line, which we define as our departure to the north, and eventually home, around mid-day Monday. Today is flight #10 and we have now hit all of our high-priority science targets at least once.

We also have a fighting chance at one last science flight during the day tomorrow, Sunday. To do that requires one last spasm of exertion from the entire team – flight crew, maintenance crew, instrument engineers, scientists and support folks, in order to get the flight done early enough to get back to Punta, pack the plane and load up in time to make it north to Santiago on Monday, Palmdale on Tuesday, and to our respective homes hopefully by Wednesday night. Everybody here is fired up to do it, but par for the course, there is a problem. The workers who pump fuel into airplanes at the Punta Arenas airport, including ours, are threatening a labor action – a strike.

Media Day in Chile

Posted on by .

From: Kathryn Hansen, NASA’s Earth Science News Team, NASA’s Goddard Space Flight Center

Video conference between IceBridge scientists in Punta Arenas, Chile, and reporters in Santiago. Credit: NASA/Sarah DeWitt

PUNTA ARENAS, Chile — In a perfect world, IceBridge researchers would make science flights over Antarctica almost every day and return home with a check next to every high-priority science flight. The 2009 campaign — the first year IceBridge made flights over Antarctica — was just about perfect. But that’s a rarity in Antarctic research where whether and unanticipated aircraft maintenance can ground flights.

During days on the ground, however, researchers keep busy. On Monday, Nov. 15, IceBridge scientists gathered at Universidad de Magallanes in Punta Arenas, Chile, to answer questions from local reporters and from reporters in Santiago via live video feed (video below).

Video credit: NASA/Michelle Williams

Missed it? Get a replay of the teleconference until Nov. 29 by calling:

Phone: Tfree:800-469-6597


Rollercoaster of Opportunity

Posted on by .

From Kathryn Hansen, NASA’s Earth Science News Team, Goddard Space Flight Center

Nov. 13, 2010

John Sonntag (left), of NASA’s Wallops Flight Facility/URS, and Michael Studinger (right), of NASA’s Goddard Space Flight Center/UMBC, evaluate the Peninsula mission on the fly. Credit: NASA/Kathryn Hansen

PUNTA ARENAS, Chile — Friday evening, IceBridge teams gathered in the hotel conference room to discuss logistics for upcoming flights. First up: weather. The audience watched the animated WRF model, a tool used for flight planning because it tells you what the weather will be like in the next 6-12 hours. On this particular morning, the model showed system after system lined up to pummel Antarctica. “Are we sure this isn’t the WTF model?” a scientists inquired.

Saturday morning, scientist and flight planner John Sonntag arrived at the airport offices with the flight decision. Weather conditions weren’t perfect, but were the best the Antarctic Peninsula had seen in a month. Given that it had been a few days since the last flight and the forecast looked to only worsen in the days ahead, mission planners decided to take the opportunity to fly under the cloud ceiling. The model predicted clear skies below 10,000 feet. “I hope they’re right,” Sonntag said.

The flight planners quickly worked up a modified version of the “Pen 23” flight plan and at 9:23 we took off for the Peninsula.

The DC-8 approaches the Antarctic Peninsula. Credit: NASA/Kathryn Hansen

We flew the planned route backward, hitting northern cloud-free regions first. Heading south, we followed the eastern side the “spine” — the crest of a mountain range that extends down the middle of the Peninsula. Unfortunately for stomachs, the spine influences weather patterns and the east side also happened to be the windy, turbulent side. The DC-8 may need to restock the little white bags!

Stomachs also suffered from the dramatic changes in altitude necessary to collect data. The measurements require a relatively consistent altitude, which can be tricky when accessing a glacier behind a rock cliff. But the pilots deftly handled the 7,000-foot-roller coaster flight line to collect data over targets also surveyed during the 2009 campaign.

Glaciers meander through the rocky terrain of the Antarctic Peninsula (right). Credit: NASA/Kathryn Hansen

Targets flown: Hektoria, Drygalski, Crane, Flask and Leppard. Each of these glaciers drain into the Larsen A and B ice shelves which broke apart in 1995 and 2002, respectively. Attlee, Hermes, Lurabee and Clifford. Each of these glaciers drains into Larsen C, which is still intact.

So what? Like a cork in a bottle, ice sheets can plug the neck of a glacier. Remove that ice shelf and the glacier more freely dumps ice into the ocean. Scientists want to keep an eye on how these glaciers continue to respond years and decades after the loss of the shelves. Crane, for example, which feeds into the remnant of Larsen B, shows little sign of slowing down.

Cruising further south, however, we encountered too many clouds so we cut across to the west side of the spine to check out the Fleming Ice Shelf. Clouds there also proved too dense, however, so we turned north back to Punta Arenas. At 8.4 hours, the modified Pen 23 became the shortest flight of the campaign — to the relief of many yellow-faced passengers.

Finishing the Arc

Posted on by .

From Sarah DeWitt, NASA’s Goddard Space Flight Center

Nov. 10, 2010 – South Pole Flight #2

After two and a half days of waiting for a replacement part to be delivered from the United States to Punta Arenas, the Operation IceBridge team is back in the air again. A new landing gear latch was hand-delivered on Tuesday afternoon at 2:20 PM. At the daily 6:00 PM science meeting, the ground crew informed us that the latch had been installed and was ready for flight. There was a hearty round of applause and a smile on everyone’s face.

Based on the weather prediction for Wednesday, the team identified two possible flight paths: a pass over the Crosson Ice Shelf or an arc over the South Pole. Models showed a low-pressure system off of the Antarctic Peninsula, and relatively clearer skies over the pole. After a second weather report in the morning, it was decided that we would do the South Pole arc – the LVIS 86b flight line – a continuation of the 2009 LVIS 86 flight line. 

The latest weather model data. Credit: John Sonntag, NASA WFF/URS.

IceBridge project scientist, Michael Studinger (NASA GSFC/UMBC), contacted the station manager at the South Pole to let him know our approximate overflight time. Apparently for folks who have been stationed at the South Pole for weeks or months during winter, this is an exciting event! The only question is, will the skies be cloud-free so we can see the station and they can see us?

8:30 AM – Today is my first flight on the NASA DC-8, so after the pre-flight briefing I made my way up to the cockpit for a front row seat. Seated behind the pilot and beside the flight engineer I buckled up and donned my headset. 

The NASA DC-8 flight crew prepares for take-off. Credit: Sarah DeWitt, NASA GSFC.

9:20 AM – Take-off! It’s a beautiful day in Punta Arenas, and the view from the cockpit is spectacular. As we head straight south I can see Route 9, the highway that hugs the coast as you head south from town to Fuerte Bulnes and San Juan. The mountains to my left are jagged and absolutely smothered in snow. The tall one looks like the Matterhorn.

9:45 AM – Today’s flight navigator is Rick Auld, an Air Force rated navigator onboard the DC-8 through the NASA Alliance Agreement with Edwards Air Force Base. He delivers a map of the South Pole arc we will fly today. The pilots explain to me that we’ll fly through enough time zones to go through Wednesday, Thursday and back again. 

The DC-8 pilots point out the narrow Antarctic time zones on the navigation map. Credit: Sarah DeWitt, NASA GSFC.

10:47 AM – Rick informs me we are about 160 miles due west of Adelaide Island. We are high above the clouds – a blanket of white in all directions.

10:50 AM – Just passed the Antarctic Circle, and we’ll begin our climb to 35,000 feet. It could be my imagination, but the highest layer of clouds look to be thinning a bit.

10:58 AM – Mission manager Frank Cutler, NASA DFRC, announces that we’re approaching the Antarctic continent, and asks the science instrument teams to check-in and declare readiness. The air is getting a bit bumpier now – the high clouds are back.

11:03 AM – Gap in the clouds ahead! The LVIS science team will use this opportunity to do some of their instrument maneuvers. Meanwhile I am catching my first ever glimpse of Antarctic ice. 

Shane Wake and Bryan Blair – LVIS engineer and principal investigator at NASA GSFC – take a look at the LVIS instrument read-out in their station near the rear of the aircraft. Credit: Sarah DeWitt, NASA GSFC.

11:20 AM – Michael informs me that we’re currently flying over the Wilkins ice shelf – or remnants of it. It broke up just a few years ago, so many very large icebergs are left floating in the sea. Image: Remnants of the Wilkins ice shelf from the window of the NASA DC-8. Credit: Sarah DeWitt, NASA GSFC.

11:32 AM – Thick cloud cover again. Time for lunch.

12:05 PM – Bryan shows me the ICESat data points we’ll be flying over today. Our path starts with a very high-terrain area over the Transantarctic Mountains and then levels out towards the end. We hope to see the mountains over top of the clouds. Some of the peaks rise to 10,000 feet, so it’s certainly possible. The flight today will enable LVIS to record a wide swath of data covering nearly every single orbit that the ICESat satellite made. Because of its polar orbit, millions of ICESat data points are clustered around the pole. During ICESat’s 7-year lifetime, its laser instruments were turned off and back on again from time to time, so there are slight differences throughout the dataset. LVIS data will provide a statistically powerful tool to calibrate the ICESat data.

12:15 PM – Rick tells me we’re 736 miles from the South Pole. Of course, we’re not flying a straight line, so it will take longer than that before we reach the pole. We’ll actually be flying an arc around the pole at 240 miles distance before crossing over the South Pole station. Clouds are still pretty heavy. We’re approaching -80 degrees latitude. 

Screen shot of Falcon View navigation map showing the flight path arc around the South Pole at a distance of 240 miles. Credit: Rick Auld, United States Air Force.

1:20 PM – We’ve just begun our arc around the pole. A layer of very smooth flat clouds blankets everything, but a few Transantarctic peaks appear in the distance. The clouds have cleared for a moment and I can see the subtle ridges that appear on the surface of the Antarctic ice. It is absolutely desolate – no signs of movement other than the clouds and the wind-blown textures atop the ice.

1:50 PM – The view is much clearer now – a stroke of good luck, since we’re passing over one of the world’s most spectacular mountain ranges. Just flew over some beautiful jagged peaks and glaciers. 

View of a Transantarctic mountain glacier from the DC-8. Credit: Sarah DeWitt, NASA GSFC

2:10 PM – We’re rounding the bend away from the mountains and onto the Antarctic plateau. We’ve passed the halfway point of our arc, and we’ve also entered the Eastern hemisphere. Apparently it’s now 4 AM on Thursday.

2:53 PM – We’ve gone half way around the world in 126 minutes. Our LVIS 86 arc is complete and now we’re heading up to 39,000 feet and flying straight towards the pole. We’re also heading straight into the sun! I’m glad I have my sunglasses.

3:10 PM – DC-8 co-pilot Dick Ewers (NASA DFRC) is talking to the South Pole on radio headset. They are ready for us to fly over. The sky is clear so they should be able to see us just fine. This has got to be one of the most amazing things I’ve experienced. Listening to the conversation between our NASA crew and the scientists at the South Pole station makes me feel very proud to be a member of this team.

3:28 PM – We are flying directly over the South Pole. The place to see it is from the cockpit window, or the nadir view camera mounted inside the bottom of aircraft. I’m squeezed in between the pilot’s seats to catch a few snapshots. Meanwhile, the compasses are spinning like crazy. 

View of the South Pole Station from the DC-8 cockpit. Credit: Sarah DeWitt, NASA GSFC

3:50 PM – Now we’re heading on a straight line from the South Pole, following the exact track we did a few days ago, just before I arrived in Punta Arenas, in order to mimic the ATM swath and compare datasets.

The smooth edge of floating sea ice off the western coast of the Antarctic Peninsula (right). Credit: Sarah DeWitt, NASA GSFC

6:25 PM – The last few hours have been extremely relaxed and quiet. Seems like everyone is conserving energy. I’m doing some yoga stretches. We should be back in Punta Arenas in a few hours. Meanwhile, the team has started looking at flight options for tomorrow. If the weather holds, we’ll do a low elevation zig-zag pattern over parts of the peninsula.

6:35 PM – We’re crossing over the edge of the Antarctic sea ice. It’s remarkable how smooth the edge is. A few lonely icebergs are floating nearby. I can see their blue color below the surface. The sun is casting a gorgeous pink-orange glow over the ocean surface.

6:40 PM – And just when I declared that everything was relaxed and quiet, the crew performed a couple of pitch and roll maneuvers. Wow!

9:25 PM – Landed after 12 hours of flying. The sunset over the Andes was worth the wait. Tomorrow I hope to fly again.

A Three-Hour Car Survey

Posted on by .

From Sarah DeWitt, NASA’s Goddard Space Flight Center

November 7, 2010

Dave Jordan (NASA ARC), Kyle Krabill (NASA WFF) and Matt Beckley (NASA GSFC) affix a GPS antenna to a pick-up truck for the three-hour Operation IceBridge car survey. Credit: Sarah DeWitt, NASA GSFC.

PUNTA ARENAS, Chile — Today marks the end of Daylight Savings Time in the United States, but the clocks remain unchanged in Punta Arenas. Just 18 hours after setting foot on Chilean soil, I was packing my bag at 5:30 this morning for a DC-8 flight over Pine Island Glacier. I thought that was an exceptionally appropriate first foray into the IceBridge mission, considering that Pine Island is one of the few Antarctic features I know quite well.

Alas, the IceBridge team and I will keep our feet on the ground for at least a few more days while we wait for a replacement airplane part to be delivered from California. The news came over breakfast as the team prepared to fly for a fourth day in a row – a welcome stroke of good luck now put on temporary hold. While the DC-8 team hustled to get the part shipped on the next available plane from L.A., others shifted their focus from the air to the ground.

The ground calibration team is really just one person – Kyle Krabill, engineer at NASA’s Wallops Flight Facility. This morning Kyle took advantage of the DC-8 downtime and set out to create a topographic map of the airport ramp. This type of map is called a “car survey” because it involves a three-hour journey criss-crossing the rectangular speck of pavement at a maximum speed of 5 miles per hour. The entire area is only about 200,000 square meters, but it varies in elevation by a factor of about one meter. An accurate elevation map of the ramp is critical for calibrating IceBridge’s airborne instruments. Kyle’s goal is an elevation map with centimeter precision.

He starts his car survey by attaching a GPS antenna to the top of a car. He carefully arranges all of the equipment and passengers before the survey begins, because even a slight difference in weight can affect the measurement. Would-be passengers must commit to the three-hour road trip or be relegated to watch from the sidelines.

Image is courtesy of Kyle Krabill/ATM team

The LVIS 86 Pole Flight

Posted on by .

From: Scott B. Luthcke, Geophysicist, NASA’s Goddard Space Flight Center

November 4, 2010, 8:05 p.m. EDT

After several days without flights due to unfavorable weather over Antarctica, the Operation Ice Bridge DC-8 is in flight supporting its latest mission. The mission today is the LVIS 86 pole flight. It’s a long 12-hour mission during which the DC-8 will navigate around the South Pole following an arc of -86 deg. latitude at an altitude of 35,000 feet. The South Pole arc will enable NASA’s Land, Vegetation and Ice Sensor (LVIS) to map the surface of the interior of the ice sheet with a 2-kilometer-wide swath, and 25-meter spatial resolution within the swath. This mission will extend the coverage around the pole first collected by LVIS during a 2009 mission. In addition to LVIS, NASA’s Digital Mapping System (DMS) will also be collecting data during this flight. Two other instruments, NASA’s Airborne Topographic Mapper and Kansas University’s MCoRDS radar, typically operate only at lower altitudes, but today both are experimenting with new operational modes and equipment that may allow them to collect data from higher altitudes with LVIS.

The LVIS surface height mapping data provide an important datum to calibrate measurements of ice sheet surface elevation obtained from the Ice Cloud and land Elevation Satellite (ICESat) laser altimeter. ICESat was in a near-polar orbit with the laser altimeter surface profiles densely converging in an arc around the south pole at -86 deg. Therefore, the swath of data LVIS is collecting today, along with that collected in the 2009 pole arc flight, intersects nearly 70 percent of ICESat orbits and provides over a million LVIS and ICESat difference observations for comparison. It’s a unique set of data leveraging the converging satellite tracks around the pole. In addition, the LVIS observations will provide an important datum to monitor long-term interior ice sheet change with respect to current and future near-polar satellite mission data. The DMS and MCoRDS systems complement and enhance the LVIS data by providing high-resolution surface imagery and bedrock topography respectively.

Principal investigator Bryan Blair and scientist Michelle Hofton are running LVIS for today’s mission. Through the magic of technology, lead instrument engineer David Rabine is supporting the mission via xchat while he is on an airplane flying back to the United States after spending the previous three weeks in the field with the instrument. LVIS obtains measurements of surface height using a laser altimeter approach. A laser pulse is transmitted from the instrument, and is reflected back from the surface where the return pulse is recorded. The distance, or range from the instrument to the reflecting surface, is computed as the round trip time of flight of the pulse divided by two (to get the one-way travel time) and then divided by the speed of light. GPS receivers are used to compute the position of the instrument, while the pointing or direction of flight of the laser pulse is determined using instrument orientation data provided by a gyro attitude sensor. The surface elevation for each laser shot can then be computed from these data using the position of the instrument, the direction of the laser pulse travel and the distance or range of the laser pulse travel to the surface.

Credit: NASA/Michael Studinger

Nearly 30 minutes into the flight the excitement ramped up as the pilots prepared to perform the LVIS instrument calibration maneuver. Everyone took their seats and strapped in. A few minutes later the go was given to perform the maneuver and the airplane pitched up and down several times followed by several rolls left and right, giving us all a roller coaster ride. After a few minutes all was clear and we were back to business.

Now, over six hours into the mission we have completed the data collection for the pole arc and are heading back to Punta Arenas, Chile. On the transit back we flew directly over the South Pole! The mission was clearly a success with mostly clear skies and a full data collection from the instruments. Everyone is looking forward to getting on the ground, having a good dinner, and getting rested up for, potentially, another flight tomorrow.

The South Pole Station was easily visible during a flight there on Nov. 4. Credit: Digital Mapping System (DMS) group

Last Sea Ice Mission for 2010

Posted on by .

Sinead Louise Farrell, Earth System Science Interdisciplinary Center (ESSIC), University of Maryland/NASA’s Goddard Space Flight Center

Oct. 30, 2010

Our internal body clocks are becoming accustomed to the early morning routine here in Punta Arenas, Chile, as we prepare for the daily mission brief and weather report before take-off. I woke up early this morning, 5:30 a.m., 20 minutes ahead of my alarm; those who know me well will tell you that’s a minor miracle! Not known for being a “morning person” I was excited today with the possibility of a 3rd sea ice flight, the last of our highest priority sea ice missions. Even the piped music during breakfast at our hotel seemed to be up beat and themed for flying!

Sinead Farrell and John Arvesen enjoy the view of the ice pack from the NASA DC-8. Photo courtesy of James Yungel.

Around 7:55 a.m. the news from the weather briefing appeared good, and we received word that today’s sea ice flight was a “go.” The weather forecast today is such that we expect some pockets of low cloud at a couple of locations along our target flight lines. Low clouds are worrisome since they restrict the retrieval of laser altimetry data, which impacts the science return of the sea ice data set. However, the team, who has seen this all before, has a few tricks up the sleeves of their flight suits! We’ll try to beat these weather systems by flying our route in a counter clockwise direction … hoping to survey the more southwesterly Amundsen Sea first and the Bellingshausen Sea later in the flight.

Today’s flight line to the west of the Antarctic Peninsula has also undergone a number of iterations. Unlike flying over the more stationary ice sheets and glaciers, sea ice is dynamic, and drifts easily under the influence of waves and wind. Even the best-laid plans often need to be altered and updated at the 11th hour, based on current conditions. The recent low-pressure systems to the west of the Antarctic Peninsula have conspired to push much of the sea ice out of the eastern Bellingshausen Sea further west into the Amundsen Sea. Originally we had planned to survey sea ice in the eastern Bellingshausen to the north and west of Alexander Island. One of our science objectives for this flight is to support our colleagues at the British Antarctic Survey (BAS) and their “IceBell” mission. The BAS team is currently on passage to South Georgia aboard the RSS James Clark Ross and they expect to reach the Bellingshausen Sea sometime around mid November.

Map of Flight Line for October 30, 2010 over the Bellingshausen and Amundsen Seas. Map courtesy of Michael Studinger.

However, given the extent of open water north of Alexander Island (see map, above) we have removed flight lines in that area and focus now on surveying the Bellingshausen to the west of Alexander Island (way-points 102n, 103n, and 104n, indicated on the map). This new plan also has the advantage of giving us extra time to sample the Amundsen Sea and repeat much of the 2009 survey. In this way we begin to build a time series of sea ice measurements over many years, which provides the data we need to look at both the interannual variability of sea ice thickness, and assess any longer term trends in the overall volume of the ice pack.

After a transit of two short hours, we reach the beginning of our survey line. Unfortunately the local weather is much worse than both the weather models and forecasts predicted. The thick, low cloud base, visible in all directions, seems to be part of a system moving faster than forecast. A moment of hope appears when a section of consolidated sea ice with long narrow leads appears beneath a break in the clouds … but hope is short lived when the clouds condense once again in all directions.

After about an hour of nervously peering through the windows on the aircraft, the decision is made to descend to a lower altitude. We’ll try to get beneath the cloud deck and switch from the high altitude Land Vegetation and Ice Sensor (LVIS) laser altimeter to the low altitude Airborne Topographic Mapper (ATM) laser system. An anxious 15 minutes pass as we descend from 35,000 feet to 1,500 feet, but suddenly we’re below the cloud deck, the ice pack appears, and there’s much cheering and clapping aboard the DC-8!

Small sea ice floes at the foot of a tabular ice berg, Amundsen Sea, 30 October 2010. Photo by Sinead Farrell.

The transit through the Amundsen Sea was busy. Small pockets of light cloud and haze appeared between the aircraft and the sea ice surface. The DC-8 pilots descended to lower altitudes ducking below the cloud deck for short periods to maximize the conditions for good data collection, before returning to the normal operating altitude of 1,500 ft. The trip though the eastern Amundsen Sea and the southern Bellingshausen was exciting; the scenery changed from thin new grey ice forming in coastal polynyas, to thicker consolidated sea ice topped with thick snow and sastrugi, intermingled with pyramidal icebergs. As a geophysicist specializing in sea ice, the long flight hours pass quickly for me as the sea ice constantly entertains with it’s ever-changing geometrical patterns of ridges, floes and leads.

Slight anxiety during the earlier part of today’s mission was finally superseded by perfect weather in the south-western Bellingshausen Sea along our route west of Alexander Island. We look forward to comparing the data collected in this region with the complementary in situ data to be collected by our colleagues on the BAS IceBell mission. A bittersweet feeling prevails as we approach the sea ice edge and cross the final few ice floes … delight in having successfully completed three high priority sea ice missions within five days, but melancholy at the thought of seeing the last of the sea ice for 2010. Ultimately these mixed emotions pass, and excitement returns with thoughts of learning what secrets our new data hold and hopes for the next IceBridge sea ice flights in Spring 2011.