A Sea Ice Mission Over the Weddell Sea

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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

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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

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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

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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

Seeing Eastern Greenland for the First Time

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From: Jason Reimuller, aerospace engineering student, University of Colorado, Boulder

My involvement with Operation IceBridge comes from a desire to better understand the polar climate and the climatic changes that are evident there. I have been working with NASA through the last five years as a system engineer for the Constellation project, while working to complete my doctoral dissertation in Aerospace Engineering Sciences at the University of Colorado in Boulder. I have also been recently involved with airborne remote sensing and LiDAR systems by completing a three year, NASA-funded research campaign that involved flying a small Mooney M20K aircraft to the Northwest Territories, Canada to better understand noctilucent clouds through synchronized observations with NASA’s Aeronomy of Ice in the Mesosphere (AIM) satellite.

This has been my first campaign with the project, participating in sorties based out of Kangerlussuaq, Greenland throughout the first two weeks of May 2010. To me, the project is a unique synthesis of personal interests — from polar climate observation and analysis, aircraft operations, remote sensing and instrument design, and flight research campaign planning. My role this year has been principally as a student with the intent to integrate the data that we collect with satellite and ground station data to better characterize glacial evolution, though I hope to become much more involved with the operations of future campaigns.

Seeing Eastern Greenland for the first time through the P-3’s windows, as its four engines lifting the aircraft easily over the sharp mountainous ridgelines and its strong airframe holding up to the constant moderate turbulence of the coastal winds being channeled through the fjords, was spectacular. I really got a strong sense of contrast between experiencing the stark minimalism of the ice cap and experiencing the aggressive terrain of the eastern fjordlands. The long flight trajectories we conducted there gave me a sense of the incredible diversity of the terrain and the low altitude of the flight plans gave me a connection to the environment not available at higher altitudes, even down to viewing the tracks of polar bears!

I have been very grateful to all the team members that have spent time with me to explain in detail the systems that they are responsible for, specifically the LiDAR systems, the photogrammetric systems, and the RADAR systems. Also, NASA pilot Shane Dover clearly explained to me the systems unique to the P-3 from a pilot perspective, which was of keen interest even though I may never log an hour in a P-3. In particular interest to me was the way John Sonntag was able to modulate complex flight plans onto ILS frequencies, providing the pilot a very logical, precise display to aid in navigating through both the numerous winding glaciers and the long swaths of satellite groundtrack. This has truly been an amazing personal experience, but upon hearing the excitement that many of the world’s top glaciologists have voiced about Operation IceBridge during my time in Kangerlussuaq, I’ve been proud to be a part of the team.

Ice Calves from Russell Glacier

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From: Kathryn Hansen, NASA’s Earth Science News Team/Cryosphere Outreach Specialist

On May 14, 2010, scientists working from Kangerlussuaq, Greenland, with NASA’s IceBridge mission observed ice calving from nearby Russell Glacier. Credit: Eric Renaud/Sander Geophysics Ltd.

IceBridge scientists spend many days in flight surveying the snow and ice from above. On research “down days,” some scientists use their day off to take in the sights. On Friday, May 14, a group of scientists with Columbia University’s gravimeter instrument — which measures the shape of seawater-filled cavities at the edge of some major fast-moving major glacier — made the trek out to Russell Glacier. In the right place at the right time, the group witnessed a calving event that sent ice cascading down the glacier’s front.

“I took burst speed photos with my Canon 40D and just kept my finger on the trigger until everything stopped moving,” said Eric Renaud, an electronic technician with Sander Geophysics Ltd. “We were lucky to witness it.”

Read more about the group’s trek in a blog post by Columbia University’s Indrani Das, and watch a time-lapse video of the calving event composed by Renaud.

Notes From the Met Hut

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From: Kyle Krabill, ATM Instrument Team Engineer, NASA’s Wallops Flight Facility

During an IceBridge science flight, a GPS instrument onboard collects measurements of the aircraft’s position. Scientists later combine the positional information with other data, such as surface elevation from the Airborne Topographic Mapper (ATM), to create accurate maps of the snow and ice. Kyle Krabill, from NASA’s Wallops Flight Facility, is an engineer with the ATM group. Instead of spending days in the air on the P-3, Krabill works from the ground to make sure the GPS information is as accurate as possible. In his own words, here’s how and why:

The GPS ground station plays an important role in collecting airborne science data. As with all GPS data there are small errors in position and the airplane GPS receivers alone cannot calculate these errors. This is where the ground station comes into play.

The ground station is set up over a fixed position and checked every day before and after the mission for a precise height to the nearest 1/2 millimeter. Knowing the exact position and also knowing that the station does not move during the flight, the data collected here can be overlayed on the plane GPS data and the position errors are canceled out. This cancellation allows for the plane GPS data to have accuracy to within a few centimeters. The ground station must be located near the area where the plane takes data so that they record data from the same set of satellites.

In Kangerlussuaq we are lucky to have access to set up our station in the Danish meteorological building, known locally as the “met hut”. The ground crew — me — has a duty to monitor the station during flight to make sure there is no break in the data due to loss of power or antenna movement.

Kyle Krabill, of NASA’s Wallops Flight Facility, worked in the “met hut” in Kangerlussuaq, Greenland, during the Arctic 2010 IceBridge mission. Credit: NASA/Kathryn Hansen

An Inland Connection?

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From: Kathryn Hansen, NASA’s Earth Science News Team/Cryosphere Outreach Specialist

Scientists have long been tracking Greenland’s outlet glaciers, yet aspects of glacier dynamics remain a mystery. One school of thought was that glaciers react to local forces, such as the shape of the terrain below. Then, researchers noticed that glaciers in different regions were all thinning together, implying a connection beyond local influences. Scientists have posed theories about what that connection might be, but the jury is still out.

Recently, the landscape in southeast Greenland has started to change. Helheim Glacer, which was thinning at 20-40 meters per year, slowed dramatically to just 3 meters per year while thinning of the nearby Kangerdlugsuaq also slowed. Further south, two neighboring glaciers showed the opposite trend and started thickening by as much as 14 meters per year. Neighboring glaciers behaving in similar ways implies a connection, but what exactly?

The IceBridge flight on May 12 will help scientists learn how changes to outlet glaciers affect the ice sheet inland. Instruments on the P-3 surveyed in detail three southeast glaciers: Fridtjof-Nansen, Mogens North and Mogens South. Next they flew four long lines mapping changes near the ocean and up to 60 kilometers inland, capturing the extent, if any, at which thinning near coast reflects on changes to the ice inland. It’s an important connection to make; while the loss of outlet glaciers alone would not contribute much to sea level rise, loss of the ice sheet could have a dramatic impact.

IceBridge crew and researchers board the P-3 on May 12 for a flight to study glaciers and the ice sheet in southeast Greenland. Credit: NASA/Kathryn Hansen

The P-3 flew over areas of sea ice wile mapping glaciers and the flight line closets to the coast. Credit: NASA/Kathryn Hansen

Mountainous terrain along Greenland’s southeast coast led to short-lived periods of turbulence and spectacular scenery. Credit: NASA/Kathryn Hansen

Eyes for Ice: In the Field with Indrani Das

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From: Kathryn Hansen, NASA’s Earth Science News Team/Cryosphere Outreach Specialist

KANGERLUSSUAQ – Kangerlussuaq International Science Support is a red, boxy building that doubles as a laboratory and a hotel for polar researchers. Upon my arrival it was quiet, nearly empty. By the end of the week, however, an influx of scientists staging field expeditions quickly filled the kitchen and halls.

Space is limited, so I share a room with Indrani Das, an ice scientist from Columbia University’s Lamont-Doherty Earth Observatory — the only other woman with the IceBridge team here in Kangerlussuaq. She works with the Gravimeter instrument, which measures the shape of seawater-filled cavities at the edge of some major fast-moving major glaciers.

Das, looking out the P-3’s window on the flight to Greenland’s Helheim and Kangerdlussuaq glaciers, has expertise that reveals a world hidden from my untrained eyes — textures in the ice that disclose, generally, how a glacier is moving.

Das wrote about her experience on the flight May 8, sprinkling her narrative with some glacial facts. Read her post here, on the Lamont-Doherty Earth Observatory’s IceBridge blog.

Around Kanger

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From: Kathryn Hansen, NASA’s Earth Science News Team/Cryosphere Outreach Specialist

KANGERLUSSUAQ — Science flights from Kangerlussuaq, or “Kanger,” last anywhere form five to eight hours. Then there are the nightly meetings to attend, an aircraft to upkeep, and weather to check. Today’s flight, however, was scrubbed due to weather and ash. What do scientists, engineers and flight crew do when they’re not flying? What’s it like in Kanger?

Kangerlussuaq is nestled at the head of a fjord in western Greenland. The town hosts a commercial airport, which until 1992 was a United States Air Force Base. Now, the town is a hub for tourists and researchers.

Some of the IceBridge researchers and crew are looking forward to the return to Thule, currently planned for May 17. Still, others appreciate the relatively snow-free springtime in Kanger, where you can simply walk to work at the airport, or go for a hike or bike ride.

Here’s a look around town and beyond:

The entirety of Kangerlussuaq, Greenland, can be seen from a nearby hill, just a short drive or afternoon hike away. NASA’s P-3 (top left) waits on the runway for the next science flight. Credit: NASA

Kangerlussuaq International Science Support houses labs, science equipement, and a place for scientists to stay. Credit: NASA

Kyle Krabill, with the ATM instrument group, picks up some Musk Ox steaks from the local butcher shop. Credit: NASA

  There’s even an 18-hole golf course in Kanger, complete with a clubhouse.  Credit: NASA

The P-3 flight crew takes a short drive and hike from Kanger to view Russell Glacier. Credit: NASA

The parents of these dogs are working animals, pulling sleds over the snow and ice. Credit: NASA

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