General – Page 5 – Operation IceBridge

Rollercoaster of Opportunity

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

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

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

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

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.

Second Weddell Sea Ice Mission and CryoSat Underflight

From: Nathan Kurtz, NASA’s Goddard Space Flight Center/University of Maryland, Baltimore County

Our flight today, Oct. 28, was a partial repeat of a mission conducted last year. The flight was to take place at 1,500 feet along the western edge of the Weddell Sea following the Antarctic Peninsula, turning south and east along the Ronne Ice Shelf, then heading north into the central Weddell Sea. The primary instruments used on this flight were a specially designed suite of laser and radar altimeters for measuring the thickness of the snow and ice underneath.

I began my journey in the cockpit of the NASA DC-8, my first time seeing what all is involved in bringing a large aircraft from the runway into the sky. We took off on schedule flying briefly around the countryside surrounding Punta Arenas, heading back over the airport ramp to calibrate some of the instruments. We then started our push towards the Weddell Sea. Along the way there were spectacular views of the normally cloud enshrouded mountains and glaciers of Tierra del Fuego. Even at an altitude of 18,000 ft the 8,000 ft peaks looked a bit too close for comfort, but the calmness and confidence of the pilots helped rid my mind of any thoughts of catastrophe.

After a couple hours transiting through serene blue skies we spotted the Antarctic Peninsula and began our descent to low altitude. My first ever science flight to the polar regions from two days ago was still fresh in my mind, but the view of the pristine landscape still captivated me. As we passed over the peninsula, there were breathtaking views of jagged brown mountains, bright white snow, sky blue glacier ice, and murky black water all mixed together in a chaotic jumble. I was struck by how truly remote and harsh the world down below was. A place only for well prepared humans and the hardiest of animals. Despite the uninviting look of the land below, I couldn’t help imagining what it might be like to ride a sled or go skiing down some of the mountains.

As we left the peninsula, we passed southward over still waters filled with icebergs, finally entering into the sea ice region to begin our science mission. We first entered into a region of small sea ice floes which had been broken up by wind and waves. The aircraft instruments showed the surface and air temperatures were near the freezing point, probably the reason for the absence of any newly growing ice in the open water areas. As we continued our flight southward we entered the consolidated ice cover of the western Weddell Sea. The region we were flying over today is some of the thickest and most compact ice in the Southern Ocean. The vastness of the sea ice cover became readily apparent as this leg of the journey consisted of miles of ice extending into the horizon in all directions. The area was a mixture of open water, freshly grown ice, smooth areas, rubble fields, ridges, and many other ice types each with intricate geometries reflecting the physical processes which shaped their formation. Towards the end of the peninsula region we turned east following the outline of the Ronne Ice Shelf. Though we couldn’t see it in the distance, evidence of its presence was all around us as numerous icebergs could be seen. The huge size of the icebergs dwarfed the surrounding sea ice, but the icebergs were held steady inside like giants chained into a prison of sea ice.

The sea ice itself looked benign and serene, like a vast unmoving and unchanging landscape. But looks can be deceptive as the aircraft instruments showed temperatures of -10 C and 60+ mph winds outside. Telltale signs of the force of wind and water acting on the ice could be seen in the piled up and crushed ice of the ridges. The wind had also blown the snow into patterns called sastrugi, some of them looked like flowers dotting the landscape. The plane marched on relentlessly throughout the day as miles of sea ice passed below us. The last leg of the science portion of the flight took us underneath the orbit of CryoSat-2, a radar altimeter launched earlier this year by ESA.

Data from the Airborne Topographic Mapper (ATM) show a swath of sea ice at the time of the CryoSat-2 overpass on Oct. 28, 2010. Data in this image are preliminary. Credit: NASA/ATM Group

One goal of this mission was to collect coincident data between IceBridge and CryoSat-2 for doing intercomparisons between the various altimeter data sets used in cryospheric research. We were a bit ahead of schedule however, so we looped back over portions of our flight line to ensure that we were still collecting data when the satellite crossed over. Finally, as the sun hung began to sink low on the horizon, hundreds of miles above us CryoSat-2 passed silently overhead covering hours of our flight track in a matter of minutes. We continued flying northward a little while longer towards the edge of the ice pack where the ice became less consolidated and more broken up. Our mission finished, we climbed high into the sky and sped back to our temporary home in Punta Arenas.

Image is courtesy of NASA/Jim Yungel

It’s difficult for me to tell much about the ice cover properties from the limited perspective of my human eyes, but memories of the journey will remain with me for a long time to come. An enduring and detailed record has also been written into the hard drives of the IceBridge instrument archives. I and other scientists are eagerly anticipating doing a thorough analysis of the data collected. Hopefully it will tell us more about what we saw today and how this record can be used to enhance our understanding of the climate system.

A Sea Ice Mission Over the Weddell Sea

From: Seelye Martin, University of Washington

The Weddell Sea mission is a pair of lines repeated from last year that extend across the sea ice from the tip of the Antarctic Peninsula to south of Cape Norvegia, and back again (see above). The flight path crosses the tip of the Peninsula, then proceeds on a long straight line to the eastern Weddell Coast, transits down the coast about 200 nautical miles, then transits back, where the sea ice coverage is at 1,500 feet. The primary instruments will be the ATM to measure sea ice freeboard and the snow depth radar for snow depth on the sea ice.

The past five days have been very difficult, in that the weather has been poor, with low clouds or storms over all of our sites. This was stressful for all of us, in that on the previous evening, we would choose a potential target, then get up at 5:00 am local, transit to the airport at 6:30, get to the airport at 7, stare at maps and imagery until 7:30, then consult with the weather office until 8 am. At this point, we would discover the weather was so marginal that we were forced to cancel. But today our forecasts showed a high pressure system over the Weddell Sea, the Chileans said go, so we flew the mission. This is the first in a series of 14 flight plans.

In this mission, our first problem involves the production of accurate weather forecasts. To produce these, we use the following sources: First, the Antarctic Mesoscale Prediction System, which at 00 and 12 UTC, produces a five day forecast at 3-hour increments. This forecast in particular shows the location and height of the cloud layers. Second, the satellite imagery acquired by the NASA Rapidfire system, pressure field forecasts from the European Center for Medium Range Weather Forecasting (ECMWF) and the expertise of Chilean Airport Meteorologists. So what’s the weather like down here? Imagine a circular icecap centered at the South Pole. Under these conditions, there would be a high pressure system over the ice cap, and a series of lows moving around the cap. Now add the Antarctic Peninsula to the icecap, a 4,000-meter-high barrier extending 700 nautical miles toward South America. The lows still rotate around the continent, but now the peninsula causes the lows to stall in the Bellingshausen Sea. This creates the bad weather for the critical region around Pine Island Bay. For the Weddell, this is the first open day since we arrived, and we hope that the mission is free of low clouds.

A second problem involves the avoidance of bird and seal colonies. Low overflights stress the birds and seals; so we need to stay 4,000 feet away from the colonies in the vertical, or 1 nautical mile in the horizontal. We are making every effort to avoid the colonies, many of which are concentrated along our path in the northern peninsula.

A third problem involves the snow depth radar. This is an innovative radar from the University of Kansas, that measures snow depth on sea ice. Last year, the transmit and receive antennas were located adjacent to one another in a fairing attached to the belly of the plane. This year, to improve performance, the receiving antennas were relocated to compartments in the wing roots, one each on each side. The relocation of these antennas involved having a contractor replace the aircraft aluminum panels with a radar transparent material, which is used instead of the aluminum panels, with the antennas mounted behind. The radar is now more sensitive, but it has yet to be tested over sea ice, something we had hoped to do on an earlier flight, so we need to allow for roughly half an hour to take data at low elevations, then analyze it, to make sure that the instrument is working properly before taking data along the line. Having this instrument work will improve the accuracy of the snow depth retrieval. So, weather, penguins, snow radar, all must all be considered for a successful flight.

Here is the timeline of the mission:

0905: Take-off to 33,000 ft, airspeed 450 kts.

1030: We are approaching the peninsula, still at high altitude. Islands are just coming into view, poking up above the clouds, this would be Greenwich Island, straight ahead. Cloud deck is below us, clouds should clear as we cross the peninsula.

1026: Approaching peninsula, high clouds

1051: Passing over the peninsula at 34,000 ft, turbulence shakes plane.

1110: Cleared peninsula, avoided penguin colonies, sea ice is visible straight ahead, dropping our altitude to 1,500 ft. Someone just handed me a paper towel, they are concerned about possible precipitation inside the plane as we descend.

1112: Descending to 1500’ for snow radar calibration.

1113: At 1,500’, approaching sea ice under clouds, snow radar is running

1115: Transiting sea ice edge. small broken floes, sunlight on ice. Surface temp from infrared radiometer is about -2 C. It is warm and sunny out here.

1146: Surface temp as low as -6C, we have good snow. Ice consists of large floes surrounded by open water, occasional nilas (thin ice). Small icebergs visible in distance. This is wonderful flying, horizon visible in all directions, blue sky above. Very different than last year. Gives some faith to the forecast.

1201: Suddenly flying above dense low clouds without breaks.

1208: Dropped to 1,000 ft, still in clouds, some turbulence. I sure hope we fly out of this.

1217: Intermittent cloudiness, now appears to be sharpening up. Pilots do not want to go below 1,000 ft. Now it is really clear again, a whole lot better.

1219: Looks really clear again, good horizon, occasional puffs of clouds, blue sky overhead.

1225: Winds up to 25 kts at right angles to the plane, Langmuir streaks in water. Winds should blow the clouds out of here. Ben reports that the snow radar is working.

1230: Return to 1,500 ft.

1311: Cross-track wind up to 31 kts.

1318: Clouds at horizon, 2 hours to the coast. Ice and blue sky still present.

1350: We are about an hour out from the eastern Weddell coast.

1400: Back into low clouds, some chop, wispy ground fog is back, surface still visible at times, still at 1,500 ft.

1413: Clear again at surface, but overcast overhead. 26 minutes to end of line. Losing the horizon. Turbulence, socked in again, no, I can still see the surface. These cloudy interludes are pretty intermittent. Can sort of see the horizon. Ben reports from early processing of snow radar, 75 cm of snow depth near the peninsula.

1435: Approaching the coast for our turn south. Then about 200 nm on the southern leg, then head back to the peninsula.

1440: Begin turn to the southwest. This is about as close as we will get to the eastern Weddell coast, the British station Halley Bay is off here somewhere, looks like we are on the new trajectory. We are in a heavy haze, but surface is still visible. Good surface visibility.

1530: Just finished traverse along the Brunt ice shelf, very beautiful as we came out from under a cloud deck.

1552: On return track to the tip of the peninsula, good surface visibility but hazy.

1700: Perfect weather on the return line, just heard from pilots that they can finish the line at 1,500 ft. Our low altitude airspeed is 250 knots.

1820: Approaching the peninsula at low altitude, weather remains excellent, beautiful sunset across the Peninsula.

1840: 15 minutes out from waypoint marking the end of the line. We can just about make out the Antarctic Peninsula. Ice is thicker adjacent to the peninsula, this is where the second year ice occurs in the Weddell Sea. The tabular icebergs we are seeing out here probably calf off the Ronne/Filchner Ice Shelves.

1850: Reached waypoint, starting to climb for home, at a sufficient altitude to avoid the penguin colonies.

1900: Cleared the peninsula, at 34,000 ft, headed for home, but encountered 60 kt headwinds.

2120: Landed at Punta Arenas, flight duration was 12.4 hrs.

Welcome to the Operation IceBridge 2010 Antarctic Campaign

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

The DC-8, parked outside the hanger at NASA’s Dryden Flight Research Center, is prepared for a instrument test flight. Credit: NASA/Michael Studinger

Oct. 17, 2010

Dryden Flight Research Center, CA — Welcome to our 2010 Antarctic campaign with NASA’s DC-8 Flying Laboratory. For the past two weeks Operation IceBridge teams have been busy installing instruments and sensors onto the DC-8 aircraft here in Palmdale, Calif., at NASA’s Dryden Flight Research Center. Over the next couple of weeks we will fly with the DC-8 over Antarctica to measure changes in thickness of the sea ice surrounding Antarctica and to monitor changes in the thickness of ice sheets and glaciers that cover 98% of the Antarctic continent.

But before we can go south we have to go through a series of test flights here in California to make sure that all the installed sensors work and to calibrate our science instruments. In order to do this we fly over target sites in the Mojave Desert that we have surveyed on the ground a few days before the test flights. The desert environment that we have selected for our test flights here is very different from the barren land of snow and ice that we will be flying over the next couple of weeks and we all enjoy the low altitude flights over the Mojave Desert, the San Gabriel Mountains and the San Andreas Fault. When the pilots ask you if it would be a problem if the belly of the aircraft is facing the sun you know that you are in the world of research flying. We did a couple of 90 roll maneuvers at high altitude over the Pacific Ocean to calibrate the antennas of the ice-penetrating radar systems that we will use to survey sea ice, glaciers, and ice sheets.

Instrument test flight over the San Gabriel Mountains in California. Credit: NASA/Michael Studinger

The IceBridge teams have enjoyed a few days of work here in warm and sunny California and we are now ready to fly to Punta Arenas in southern Chile, which will be the base of operation for our Antarctic flights. We are looking forward to another successful campaign with exciting new data and spectacular Antarctic scenery.

Back from Greenland, No Rest for the Weary

NASA and university partners returned from Greenland on May 28, concluding Operation IceBridge’s 2010 field campaign to survey Arctic ice sheets, glaciers and sea ice.

Over the span of almost 10 weeks, crew flew 28 science flights between the DC-8 and P-3 aircraft. Flight paths covered a total of 62,842 nautical miles, equivalent to about 2.5 trips around Earth at its equator. Credit: NASA

IceBridge — the largest airborne survey ever flown of Earth’s polar ice — has now completed two successive Arctic campaigns, adding a multitude of new information to the record from previous surveys.

Continue to follow the IceBridge blog and twitter feed to read updates as science results emerge. Also hear from scientists already planning the return to Antarctica this fall.

IceBridge project scientist Michael Studinger, recently back from the field, offered words of thanks to those who helped made the 2010 Arctic campaign a success.

“A project of this size with two aircraft and multiple deployment sites and a fairly complex instrument payload is only possible with the support of many people. I would like to thank everyone from NASA’s Dryden Aircraft Operations Facility, NASA’s Wallops Flight Facility and NASA’s Earth Science Project Office, who all provided excellent support for Operation IceBridge. We also had excellent support from the NASA instrument teams, the science teams from the universities, and many of our science colleagues, both, from the teams in the field and from people back home in the labs. IceBridge also would like to thank the many people in Kangerlussuag and at Thule Air Base in Greenland who provided excellent support while we were there. We could not have accomplished our goals without their terrific help.”

Michael Studinger (right) readies for a science flight from Kangerlussuaq, Greenland, during the Arctic 2010 IceBridge field campaign. Credit: NASA/Jim Yungel

Jakobshavn in 3D

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

For the science teams, aircraft down days and no-fly days are data processing days. Below is an example of a laser scan, from the Airborne Topographic Mapper (ATM) instrument, of the calving front of Jakobshavn Isbræ (Sermeq Kujalleq). The 3D illustration of the data is at least as spectacular as the view out of the aircraft window. You are looking at a more than 300-foot-high cliff with huge icebergs and ice mélange — a dense pack of calved icebergs — in the fjord. Understanding the physics of calving and the role the ice mélange plays in this process are hot topics in glaciology. Transforming calving physics into realistic models of terminus behavior is crucial for reliable predictions of future sea-level rise. Calving fronts are not only quite spectacular features to watch but also important for understanding the mass balance of the Greenland Ice Sheet.

Credit: Kyle Krabill and the NASA ATM team