An Active Arctic: Where Sea Ice Meets the Midnight Sun

The German icebreaker Polarstern lit up on every deck, acting as a beacon for researchers navigating the Arctic terrain. Credit: University of Maryland / Steven Fons
The German icebreaker Polarstern lit up on every deck, acting as a beacon for researchers navigating the Arctic terrain. Credit: University of Maryland / Steven Fons

By Emily Fischer, Goddard Space Flight Center

In the early 1900s, Ernest Shackleton attempted to travel across Antarctica, but as they neared the continent his ship became stuck in an pack of sea ice and was slowly crushed before it reached the landmass. Over 100 years later and on the opposite side of the globe in the Arctic, researchers in the massive, double-hulled icebreaker, Polarstern, are also stuck in a pack of sea ice – but this time on purpose. And this ship isn’t sinking any time soon.

Polarstern is the operational center for the Multidisciplinary drifting Observatory for the Study of Arctic Climate, or MOSAiC. The first expedition of its kind, MOSAiC is an international mission exploring the Arctic climate system year-round, with more than 100 scientists and crew members from 20 nations living aboard the research vessel.

Intentionally trapping itself in the sea ice, Polarstern drifts with the floe, which is a large pack of floating sea ice. Researchers set up “little cities” on the ice where they take measurements using delicate instruments. While it appears that the sea ice they walk on to reach these camps is stationary, everything is actually slowly drifting as wind and ocean currents push the gigantic slabs of ice.

Steven Fons (bottom row, second from the right) and his ice coring team after successfully drilling sea ice samples. Each core will be analyzed at the labs aboard Polarstern. Credit: University Center in Svalbard / Calle Schönning
Steven Fons (bottom row, second from the right) and his ice coring team after successfully drilling sea ice samples. Each core will be analyzed at the labs aboard Polarstern. Credit: University Center in Svalbard / Calle Schönning

MOSAiC is a multidisciplinary expedition, as researchers from a variety of fields – including marine biology, meteorology, and oceanography – collaboratively study Arctic changes.

“It’s more of a process study,” explained Steven Fons, a Ph.D. candidate at the University of Maryland and NASA’s Goddard Space Flight Center, who studied sea ice from March to May of this year. “The idea, then, is once everybody collects this data, we can compile everything and learn about the sea ice in the ocean, and the atmosphere and the ecology.”

Sea ice is an integral part of the Arctic climate system because it sits directly between the ocean and the atmosphere, moderating the exchange of heat and moisture. An important climate indicator, sea ice research identifies changes in other Arctic climate systems, including the ocean, atmosphere, ecology, and biogeochemical cycles. Basically, studying sea ice can give greater insight into how the entire Arctic is reacting to climate change.

Researchers haul their equipment to their field sites through snow blown by harsh winds. One researcher, a polar bear guard, carries a rifle on his back in case of an emergency. Credit: Alfred Wegener Institute / Delphin Rouché
Researchers haul their equipment to their field sites through snow blown by harsh winds. One researcher, a polar bear guard, carries a rifle on his back in case of an emergency. Credit: Alfred Wegener Institute / Delphin Rouché

For a small group of MOSAiC researchers, every Monday was a 14-hour workday spent at “Dark Sites,” named so because they are isolated from the bright lights of Polarstern. After traveling over a mile on snow machine, the team used hollow drills to remove cylindric cores from the sea ice floe. In the labs aboard Polarstern, these samples revealed the fascinating characteristics of sea ice.

“As ice forms, it will eject the salt away as it’s freezing,” said Fons. “The longer it stays around, the more salt essentially drains out of it.” Basically, high salt levels tell researchers that this particular ice formed in the most recent winter. This can reveal how the Arctic adjusts to higher temperatures, as the region is warming at a rate more than twice the global average.

In the Arctic, wind chill can reach frigid temperatures as low as minus 70 degrees Fahrenheit. Working in the cold without hand protection was impossible, so Fons wore thin gloves underneath his bulky mittens, which he removed when handling small objects. Even so, frequent warming breaks were necessary, which meant simple, one-minute tasks could take 10 times longer in Arctic conditions.

“Some of the really cold days, you can only last 30 seconds at a time taking off your big mittens,” he recounted. “You just have to put five zip ties on this cable, perfect. It should take one minute to do, but it would take 20 minutes because you have to keep warming your hands and [the zip ties] keep breaking in the cold.”

Native to Wisconsin, Fons is no stranger to subzero winters. Nonetheless, during this expedition he witnessed temperatures unlike anything he had ever experienced before. Icy winds bit into any exposed skin. His only relief: a thick, bushy beard and about ten layers of clothing.

Steven Fons bundles up in the subzero temperatures with a fur-lined hat, multiple face-coverings, and nine or ten layers underneath his protective jacket. Credit: University Center in Svalbard / Calle Schönning
Steven Fons bundles up in the subzero temperatures with a fur-lined hat, multiple face-coverings, and nine or ten layers underneath his protective jacket. Credit: University Center in Svalbard / Calle Schönning

In an ever-changing environment, researchers’ locations can be difficult to determine on the ice cover, which can literally shift beneath their feet. For MOSAiC, every measurement is paired with a GPS coordinate. However, the ice drifts, and so the latitude and longitude change every day. Instead, the immense icebreaker Polarstern is used as a point of reference, a sort of ground zero for field navigation.

“You’re given a position away from the ship, so a certain distance of x and y, and that will theoretically never change,” Fons explained. But even this system has its obstacles. “If the ice broke up and the ship moves a little bit, then you can lose your x-y positions, so it didn’t always work.”

Helicopters and planes accompany Polarstern, getting a birds-eye view of the stark white landscape. Flying high above the floe, planes take airborne measurements in a similar way to Operation IceBridge. Fons does research using data from NASA’s ICESat-2 – the satellite that surveys glaciers and sea ice around the globe – and he was lucky enough to validate some of the satellite’s measurements while researching with MOSAiC.

“On the ship, since we’re constantly drifting with the ice, we don’t exactly know where we’re going to be on any given day,” he said. “We got lucky that we happened to be drifting one day over a spot that ICESat-2 was going to fly over. We were able to jump on that opportunity and schedule a helicopter flight.”

Seasonal changes near the poles are unlike anywhere else on Earth. Summer and winter are really the only seasons these regions experience, characterized by a dramatic transition between complete darkness during winter days to total sunlight during the summer. Ten days after reaching Polarstern, Fons witnessed his first Arctic sunrise. As summer came, the Sun sailed over the horizon for longer and longer each day until it refused to set, resulting in the phenomenon of the “midnight sun.”

The Sun at midnight on a day when it never dipped below the horizon. The North Pole, referred to as the land of the midnight sun, experiences about five months of total darkness and about six months of never-ending sunlight. Credit: University of Maryland / Steven Fons
The Sun at midnight on a day when it never dipped below the horizon. The North Pole, referred to as the land of the midnight sun, experiences about five months of total darkness and about six months of never-ending sunlight. Credit: University of Maryland / Steven Fons

Ice dynamics, or the movement of ice slabs in the floe that changes the terrain, were a trademark of Fons’ three months on Polarstern. Sometimes, the researchers would wake up to massive leads, or ice fractures, blocking their usual routes. Other days, research tents would be buried in ice piles from leads that closed to form towering ridges. Sea ice dynamics had a wide appeal for study among MOSAiC teams. Below the floe, marine biologists and ecologists studied microorganisms. Within the ice itself, sea ice researchers examined crystallization patterns.

“With MOSAiC, what people are able to do is look at the ice at so many different scales and through many different lenses,” Fons summarized.

An ice lead converged to form a ridge of precariously piled slabs of ice. Credit: University of Maryland / Steven Fons
An ice lead converged to form a ridge of precariously piled slabs of ice. Credit: University of Maryland / Steven Fons

 

Chasing Satellites with Jacques Cousteau

acques Cousteau and his team of expert divers were a key part of the success of the 1975 NASA-Cousteau Bathymetry Experiment. In this photo from left to right: Bernard Delemotte, Chief Diver; Henri Garcia; Jean-Jérome Carcopin, and Jacques Cousteau. Photo credit: NASA
Jacques Cousteau and his team of expert divers were a key part of the success of the 1975 NASA-Cousteau Bathymetry Experiment. In this photo from left to right: Bernard Delemotte, Chief Diver; Henri Garcia; Jean-Jérome Carcopin, and Jacques Cousteau. Photo credit: The Cousteau Society (preserved as large format photo at NASA’s Goddard Space Flight Center)

By Laura Rocchio, Goddard Space Flight Center

Leaving from Nassau on a Tuesday night in August 1975, Jacques Cousteau and his team set out on the Calypso for a three-week expedition designed to help NASA determine if the young Landsat satellite mission could measure the depth of shallow ocean waters.

For days, the Calypso played leapfrog with the Landsat 1 and 2 satellites in the waters between the Bahamas and Florida. Each night, it sailed 90 nautical miles to be in position for the morning overpass of the satellite.

Ultimately, research done on the trip determined that in clear waters, with a bright seafloor, depths up to 22 meters (72 feet) could be measured by Landsat.

The primary test site for the expedition was just west of the Berry Islands on the northern edge of the Great Bahama Bank. The location was chosen as the prime testing site because it gradually changed depth from one meter to deep ocean in a short north-south span (25 nautical miles). This natural-color Landsat 8 image acquired on March 23, 2019, shows where the northern Great Bahama Bank meets the deep ocean. Image credit: NASA/USGS Landsat
The primary test site for the expedition was just west of the Berry Islands on the northern edge of the Great Bahama Bank. The location was chosen as the prime testing site because it gradually changed depth from one meter to deep ocean in a short north-south span (25 nautical miles). This natural-color Landsat 8 image acquired on March 23, 2019, shows where the northern Great Bahama Bank meets the deep ocean. Image credit: NASA/USGS Landsat

This revelation gave birth to the field of satellite-derived bathymetry and enabled charts in clear water areas around the world to be revised, helping sailing vessels and deep-drafted supertankers avoid running aground on hazardous shoals or seamounts.

“It was a tremendous example of how modern tools of scientists can be put together to get a better understanding of this globe we live on,” the Deputy NASA Administrator, George Low, said of the joint Cousteau-NASA expedition in a 1976 interview.

But it couldn’t have happened without the world’s most famous aquanaut, his team of expert divers, and the Calypso.

Astronauts and Aquanauts Together

The ocean’s vastness made Cousteau an early supporter of satellite remote sensing.

Cousteau, by then a decades-long oceanographer, was keenly aware that ocean monitoring from above would be necessary to understand the ocean as part of the interconnected Earth system and to raise the awareness requisite for protecting the sea. There was a growing recognition in the 1970s that helping the planet required understanding the planet.

“Everything that happens is demonstrating the need for space technology applied to the ocean,” Cousteau said during a 1976 interview at NASA Headquarters.

George Low, the Deputy NASA Administrator, himself a recreational diver, connected Jacques Cousteau with former Apollo 9 and Skylab astronaut Russell Schweickart. Schweickart was heading up NASA’s User Services division and both he and Cousteau were looking for ways to advance Earth science.

At the time, it was theorized that the new Landsat satellites might be useful for measuring shallow ocean waters. New deep-drafted supertankers were carrying crude oil around the globe, and to avoid environmental catastrophes it had become important to know where waters in shipping lanes were less than 65 feet (20 meters).

For this experiment, Landsat data was downlinked to NASA Goddard Space Flight Center in Greenbelt, Maryland where it was processed into depth contour data. This was uplinked to the Applications Technology Satellite-3 (ATS-3) and then sent via Very High Frequency (VHF) relay to a VHF receiver system that had been installed on the Calypso for an earlier 1974 experiment in the Gulf of Mexico. Image credit: NA
For this experiment, Landsat data was downlinked to NASA Goddard Space Flight Center in Greenbelt, Maryland where it was processed into depth contour data. This was uplinked to the Applications Technology Satellite-3 (ATS-3) and then sent via Very High Frequency (VHF) relay to a VHF receiver system that had been installed on the Calypso for an earlier 1974 experiment in the Gulf of Mexico. Image credit: NASA

To establish if Landsat could accurately measure ocean depth from space, simultaneous measurements from ships, divers and the satellite were needed.

Schweickart knew a coordinated bathymetry expedition was an essential step. He had honed his diving expertise while training for his Skylab mission in NASA’s water immersion facility and was enthusiastic about scuba work. Teaming with Cousteau was a natural fit.

Chasing Satellites

An elaborate experiment was designed to determine definitively if multispectral data from the Landsat satellites could be used to calculate water depth. The clear waters of the Bahamas and coastal Florida were selected as the test site.

The experiment design involved two research vessels, the Calypso and Johns Hopkins University Applied Physics Lab’s Beadonyan, being in position, or “on station,” when the Landsat 1 and 2 satellites went overhead on eight different days (four consecutive days on each of two weeks).

The overall concept was simple: the research ships would use their fathometers to measure water depth at the exact same time that the satellite flew overhead and then those measurements would be compared (the simultaneous measurements eliminated any environmental or atmospheric differences that could have complicated comparisons). But realizing that plan took extraordinary coordination.

A detail from the planning map used for the 1975 NASA-Cousteau Bathymetry Experiment showing the Berry Islands. The hatched lines show the location of Landsat scene edges. Click on image for full map. Image credit: NASA
A detail from the planning map used for the 1975 NASA-Cousteau Bathymetry Experiment showing the Berry Islands. The hatched lines show the location of Landsat scene edges. Image credit: NASA

As the Landsat satellite flew overhead, Cousteau and his team of divers made a series of carefully timed measurements of water clarity, light transmission through the water column, and bottom reflectivity. This was done both near the Calypso and at two sites 60 meters from the Calypso using small motorized Zodiac rigid inflatable boats.

To make the light transmission measurements, two teams of divers had to use a submarine photometer to measure light at the water’s surface, one meter under the water and in 5-meter increments to the bottom (down to 20 meters).

The divers had to hold the photometer in a fixed position looking up and cycle through four different measurements. They also used specially filtered underwater cameras to measure bottom reflectivity (assisted by gray cards for reference). Everything was carefully timed. Schweickart and President Gerald Ford’s son Jack helped with these underwater measurements.

To make the precision measurements, the skill of these divers – including Cousteau’s chief diver, Bernard Delemotte – was essential.

“I was in charge of the divers,” Delemotte explained in a recent interview. “We were very convinced that we could do serious work together [with NASA].”

Before the satellite overpass, the Calypso and Beayondan were in position, anchored side-by-side, and ready to make all specified measurements.

“Two small Zodiacs left from the Calypso just before the satellite passage,” Delemotte recalls.

The Zodiacs stationed themselves 200 feet (60 meters) from the Calypso, and at the moment that the satellite was overhead someone on the Calypso would call to the divers through the portable VHF radio: “Go now!”

The divers would then start the series of prescribed measurements.

Using these measurements, scientists developed mathematical models describing the relationship between the satellite data and water depth, accounting for how far the light could travel through water, and how reflective the ocean floor was.

“Particular thanks” was given to Cousteau’s team of divers in the experiment’s final report “for their dedication and expertise in the underwater phases of the experiment, without which, measurements of key experimental parameters could not have been made.”

The diving prowess of Cousteau, Delemotte, and the Calypso crew added inextricably to the realm of satellite-derived bathymetry. Because of data collected during the NASA-Cousteau expedition, charts in clear water areas around the world were updated, making sea navigation safer. It was the precision measurements made by Delemotte and Cousteau’s team of divers that made bathymetry calculations for those chart updates possible.

Prepping for a High Altitude Flight

NASA's high-altitude ER-2 aircraft was part of the IMPACTS field mission to study snow in January and February, 2020. Credit: NASA/Katie Stern
NASA’s high-altitude ER-2 aircraft was part of the IMPACTS field mission to study snow in January and February, 2020. Credit: NASA/Katie Stern

By Katie Stern, IMPACTS’ Deputy Project Manager / HUNTER ARMY AIRFIELD, SAVANNAH, GEORGIA/

“Get in there and check it out!”

I was encouraged by “Corky” Cortes from the NASA ER-2 Life Support Team to see how the pilots prepare for their flight. This was my first NASA field campaign with the ER-2, a high altitude aircraft requiring a Life Support Team to help maintain the health and safety of the pilots. This aircraft is highly specialized and has been modified by NASA for conducting airborne science research.

NASA ground crew preparing the ER-2 for a science flight at Hunter Army Airfield in Savannah, Georgia. There are seven scientific instruments located on the aircraft for the IMPACTS project and they are used to study snowstorms. Credit: NASA/Katie Stern
NASA ground crew preparing the ER-2 for a science flight at Hunter Army Airfield in Savannah, Georgia. There are seven scientific instruments located on the aircraft for the IMPACTS project, used to study snowstorms. Credit: NASA/Katie Stern

As the Deputy Project Manager for the NASA IMPACTS project (Investigation of Microphysics and Precipitation for Atlantic Coast-Threatening Snowstorms), I spent January and February at Hunter Army Airfield in Savannah, Georgia, managing the deployment site for the ER-2 and the mission scientists. Our project is specifically focused on studying snowbands across the Eastern seaboard. The ER-2 plays a critical role in capturing remote sensing data to better predict the severity of storms.

Deputy Project Managers Fran Becker and Katie Stern awaiting the ER-2 science flight. Cross winds were mild and the ER-2 was able to take off. Credit: NASA
Deputy Project Managers Fran Becker and Katie Stern awaiting the ER-2 science flight. Cross winds were mild and the ER-2 was able to take off. Credit: NASA

As a new member to the team, I was unfamiliar with what the Life Support crew and pilot needed to do before each flight. Determined to find out, I peered into the tiny office and saw Joey Barr from Life Support setting up the dressing area for pilot Cory Bartholomew. The full pressure suit was completely unzipped, its green lining visible. It was laid out on the floor to make the dressing process easier. Shiny black boots with metal stirrups used for the ejection seat were placed neatly on both sides of the vinyl chair. Behind Cory were two bright yellow gloves and a space helmet carefully placed on a donut shaped pillow. Everything was ready to go. All we needed was the pilot.

Prior to every flight, the ER-2 Life Support team lays out all of the equipment to aid in an easier suiting up process. The suits weigh between 35-40 pounds and every pilot wears long underwear inside the suit. It is important to make sure that the pilot does not overheat during the suiting process so the pilots are usually assisted by a Life Support crew member. Credit: NASA/Katie Stern
Prior to every flight, the ER-2 Life Support team lays out all of the equipment to aid in an easier suiting up process. The suits weigh between 35-40 pounds and every pilot wears long underwear inside the suit. It is important to make sure that the pilot does not overheat during the suiting process so the pilots are usually assisted by a Life Support crew member. Credit: NASA/Katie Stern

The actual suiting-up process looked a bit cumbersome. I could see why it would be easy to overheat if you tried dressing yourself. One foot, after another, Cory stepped into the matte yellow and green suit and then poked his head through a metal collar, which was used to secure his space helmet.

The two men worked silently, adjusting the suit, putting on the torso harness, tightening straps, and going over the checklist in their heads. They’ve both been through this routine hundreds of times, but for me it was fascinating to see the thought and care going into each movement.

ER-2 Pilot Cory Bartholomew being helped into his full pressure suit by Joey Barr from the Life Support Team. Credit: NASA/Katie Stern
ER-2 Pilot Cory Bartholomew being helped into his full pressure suit by Joey Barr from the Life Support Team. Credit: NASA/Katie Stern

After a few adjustments to the velcro reading glasses that went inside the helmet, Cory snapped the visor shut, and Joey put on his headset to begin the suit pressure checks. A small yellow box filled with liquid oxygen was then connected to the front of the suit with a hose. These pressurized suits along with the liquid oxygen (LOX) allow pilots to fly at an altitude of 65,000 feet, so high the pilots can see the curvature of the Earth.

Joey Barr making sure that Cory Bartholomew is happy with his glasses. Once the helmet is shut, the pilot will not open the visor again until after landing. Credit: NASA/Katie Stern
Joey Barr making sure that Cory Bartholomew is happy with his glasses. Once the helmet is shut, the pilot will not open the visor again until after landing. Credit: NASA/Katie Stern

A few moments later the suit began to inflate and Cory motioned for me to tap on his knee to feel the outward force from the pressure check. A few more checks were conducted and within 15 minutes Cory was ready to be escorted to the van that would take him out to the aircraft.

“If the pilot has an 8 hour mission, how does he eat or drink once he’s in his suit?” I asked Joey, knowing that it was probably a common question.

“See this small hole at the bottom of the helmet? We have a whole selection of food that we can give the pilots and they drink it through a straw that goes into that hole. They can have applesauce, beef stew, key lime pie, peaches, chocolate pudding, you name it!” Joey was excited to share the menu with me and I couldn’t help thinking that the key lime pie sounded pretty good. And after actually trying it, I can confirm it does taste exactly like key lime pie, just put through a blender.

The pilots get to choose what type of inflight food options they bring along. Squeezing the Key Lime Pie out of the tube was not very easy. Credit: NASA/Katie Stern
The pilots get to choose what type of inflight food options they bring along. Squeezing the Key Lime Pie out of the tube was not very easy. Credit: NASA/Katie Stern

After answering a few other questions of mine, Joey escorted Cory out to the jet. Witnessing the amount of preparation to get ready for the flight only made me want to learn more about the ER-2 and its history. It also gave me a huge appreciation for all of the expertise that goes into ensuring the success of the IMPACTS mission and other NASA missions.

Pilots Tim Williams and Cory Bartholomew pose in front of the NASA ER-2 with Project Manager Bernie Luna and Deputy Project Manager Katie Stern. Credit: NASA
Pilots Tim Williams and Cory Bartholomew pose in front of the NASA ER-2 with Project Manager Bernie Luna and Deputy Project Manager Katie Stern. Credit: NASA

A Breathtaking View – Literally

Credit: NASA / Jessica Merzdorf
Credit: NASA / Jessica Merzdorf

By Jessica Merzdorf / GRAND MESA LODGE, COLORADO

After visiting with part of the SnowEx 2020 airborne team, we headed up the mountain to rendezvous with the ground team, stationed at Grand Mesa Lodge.

“Does anyone have a headache?” asked Jerry Newlin, SnowEx operations manager, as we left the little town of Delta and the rugged brown foot of the mountain range loomed up in front of us.

“Nope, feeling great” was our answer at the time. We traveled up the winding roads, commenting on the views that became more incredible the higher we went, and arrived at Grand Mesa Lodge in time for dinner and the evening briefing with the team.

But later that evening, at 10,500 feet, both video producer Ryan Fitzgibbons and I started developing symptoms of altitude sickness. Lower oxygen levels at higher elevations can cause headaches, nausea, shortness of breath, dizziness and other symptoms as the body adjusts. Sometimes the symptoms resolve on their own as the body gets used to the conditions; after a long, rough night of intense headaches and nausea, I gratefully accepted an herbal medication from the Grand Mesa Lodge owners. (Severe cases of altitude sickness require quickly moving back down to lower elevations. The ops team kept a close eye on me to make sure I didn’t need medical attention.)

After I took a nap back at my cabin and started to feel better, we checked in with Jerry and were cleared to snowmobile up to the snow pits.

The ground team’s daily “commute” varies depending on where they’re working that day, but it can be as much as 16 miles of hills, curves, bouncy stretches and incredible views of the valley below.

The SnowEx team reached the field sites via daily snowmobile trips. The ride is bumpy and can take 45 minutes to 2 hours, depending on where they’re working on the mesa. They towed their instruments and gear on sleds behind the snowmobiles. Credit: NASA / Jessica Merzdorf
The SnowEx team reached the field sites via daily snowmobile trips. The ride is bumpy and can take 45 minutes to 2 hours, depending on where they’re working on the mesa. They towed their instruments and gear on sleds behind the snowmobiles. Credit: NASA / Jessica Merzdorf

At each of the snow pits in this 3-week phase, the SnowEx ground team digs until they reach the ground, exposing a “wall” of snow where they take their measurements: Depth, density, water content, temperature, reflectance and particle size.

“We can see, and even hear, how the snow’s characteristics change from top to bottom,” said Chris Hiemstra, a researcher with the U.S. Army Corps of Engineers’ Cold Regions Research and Engineering Laboratory (CRREL). “The newest snow at the top is fluffy and loose. Below that, the wind has packed it into dense layers. The snow at the bottom has more water and the particles are sharper. When you dig into it, it sounds different than the other layers at the top.”

When we stopped by deputy project scientist Carrie Vuyovich’s pit, we heard the story of the “strong work mouse,” and saw a snow statue (made from wind-packed snow, incidentally) built in the mouse’s honor.

The SnowEx “mascot” for 2020 was the “strong work mouse,” honoring the small field mice that visited the snow pits during the first two weeks of data collection. Suzanne Craig of the National Snow and Ice Data Center records data next to a snow sculpture of the strong work mouse. Credit: NASA / Jessica Merzdorf
The SnowEx “mascot” for 2020 was the “strong work mouse,” honoring the small field mice that visited the snow pits during the first two weeks of data collection. Suzanne Craig of the National Snow and Ice Data Center records data next to a snow sculpture of the strong work mouse. Credit: NASA / Jessica Merzdorf

“There were these little mice that came to visit us in the first couple of weeks,” she said. “We’d be in pits, and these little mice would come running across the snow – one came down into the pit and hung out with us for a while, another team had a mouse running along beside them, and another member had a mouse come right up next to his boot. So that became our mascot – the ‘strong work mouse.’”

Not all of the research takes place in pits. Team members on skis used snow micro-penetrometers (SMP’s) to measure hardness and microstructure throughout the snow layers with incredibly high precision: The SMP takes 250 measurements every millimeter. Other snowshoe-wearing scientists used MagnaProbes, which have a magnetic probe that goes into the snow and a “basket” that rests on top. The distance between the two parts provides a highly accurate, GPS-tagged measurement of snow depth, and is many times faster than writing depth measurements in a notebook.

SnowEx 2020 project scientist Hans-Peter (HP) Marshall drives his snowmobile in a tight clockwise circle called a “radar Hiemstra spiral”, taking active radar measurements of the snow. The Twin Otter aircraft carrying SWESARR will later fly over this circle and take similar measurements. Credit: NASA / Jessica Merzdorf
SnowEx 2020 project scientist Hans-Peter (HP) Marshall drives his snowmobile in a tight clockwise circle called a “radar Hiemstra spiral”, taking active radar measurements of the snow. The Twin Otter aircraft carrying SWESARR will later fly over this circle and take similar measurements. Credit: NASA / Jessica Merzdorf

SnowEx project scientist Hans-Peter (HP) Marshall and Mike Durand, an associate professor at Ohio State University, used snowmobiles to create tight clockwise circles of radar measurements. This spiral sampling strategy is called a “Hiemstra spiral” after Chris Hiemstra, who developed them using the MagnaProbe, Marshall said. His snowmobile carried an active radar instrument, which generates pulses that bounce off the snow and the layers.  These pulses are timed to nanosecond accuracy, allowing estimates of snow depth, water equivalent and thickness of major layers, 100 times per second. Durand’s had a passive instrument that measured the radiation naturally generated by earth and scattered by snow.

If these measurements sound familiar, that’s because they’re the same types, frequencies, and polarizations as the airborne instrument SWESARR, Marshall said. The Twin Otter aircraft flies over these spirals and takes the same measurements in the same location. Later, the two teams can compare the data and see how well they align with each other and the standard snow pit and depth observations.  Data from both the active radar and passive microwave sensors on SWESARR will be combined to estimate snow properties such as snow water equivalent.

On the last day of data collection, Vuyovich revealed that the team had successfully collected data from 153 snow pits and 6 SWESARR flights in just three weeks — even more than originally planned.

SnowEx 2020 operations manager Jerry Newlin (ATA Aerospace) caught Chris Hiemstra (U.S. Army Corps of Engineers’ Cold Regions Research and Engineering Laboratory) in the reflection of his goggles during one of their daily snowmobile commutes. "It looks like Chris is collecting data on the Moon," Newlin said. Credit: NASA / Jerry Newlin
SnowEx 2020 operations manager Jerry Newlin (ATA Aerospace) caught Chris Hiemstra (U.S. Army Corps of Engineers’ Cold Regions Research and Engineering Laboratory) in the reflection of his goggles during one of their daily snowmobile commutes. “It looks like Chris is collecting data on the Moon,” Newlin said. Credit: NASA / Jerry Newlin

But SnowEx is off to a great start, not wrapping up. SnowEx 2020 has another phase: The time series. Smaller, local ground teams are currently performing weekly snow measurements at sites in Colorado, Utah, Idaho, New Mexico and California through March, and bi-weekly in April and May, at the same time as UAVSAR overflights. UAVSAR is an L-band InSAR (radar) instrument developed by NASA’s Jet Propulsion Laboratory. The time series will give the researchers data on how snow changes over time, especially as it melts in the spring.

When asked about the best memories they will take home from the mesa, each team member’s answer was the same: The team.

“The best part has been the team,” Vuyovich said. “The people that have been out here have been working super hard, and it’s been a lot of fun.”

“These kinds of intensive field campaigns form bonds that last a career,” said Marshall. “Chris Hiemstra and I met during the last big series of field experiments 17 years ago, and we have been working together ever since.  The younger generation in particular really stepped up this campaign – it will be exciting to see where their careers take them.”

Snow Science Two Miles in the Sky

Grand Mesa, Colorado has an elevation of 10,500 feet, and from the Land’s End Observatory, you can see across the valley to Utah. The large, flat surface of the mesa is perfect for SnowEx 2020’s instrument testing and validation activities. Credit: NASA / Jessica Merzdorf
Grand Mesa, Colorado has an elevation of 10,500 feet, and from the Land’s End Observatory, you can see across the valley to Utah. The large, flat surface of the mesa is perfect for SnowEx 2020’s instrument testing and validation activities. Credit: NASA / Jessica Merzdorf

By Jessica Merzdorf / GRAND MESA LODGE, COLORADO

What is it like to do science nearly 2 miles above sea level?

At a majestic 10,500 feet elevation, Grand Mesa is the world’s tallest mesa, or flat-topped mountain. It’s also the site of an intense month of data collection by NASA’s SnowEx 2020, a ground and airborne campaign testing a variety of instruments that measure the water contained in winter snowpack.

Snow is vital for Earth’s ecosystems and humans, from its temperature-regulating reflection of sunlight and insulating properties, to its life-sustaining water as it melts in the springtime. SnowEx is taking coordinated measurements on the ground and in the air to compare how well different instruments work in different conditions. Not only does this help them improve measurement techniques in the future, but eventually, NASA can use this information in developing a future snow satellite mission.

The “golden” measurement they’re after is snow water equivalent, or SWE (pronounced “swee”).

“SWE is our measure of the volume of water held in the snowpack,” said Carrie Vuyovich, a research scientist at NASA’s Goddard Space Flight Center and SnowEx 2020’s deputy project scientist. “It’s such a crucial measurement because the winter snow is a natural reservoir – when it melts in the spring, it feeds the groundwater, lakes and streams.”

To understand SWE, imagine taking a cubic foot of snow, and measuring how much water is left in the container after you melt it. The amount of water depends on how densely packed the snow is and how big its particles are. Measuring these properties for small amounts of snow and calculating SWE is fairly simple – but measuring it spatially for an entire snowpack over a large mountain range? That requires instruments on planes or satellites that can sense snow properties from a distance in bigger swaths.

We met up with SnowEx operations manager Jerry Newlin of ATA Aerospace on Monday. We were invited to stay with the team during their final week of data collection for this phase of the project. Our first stop was with the airborne team, at Montrose Regional Airport in Montrose, Colorado.

When we arrived, the DHC-6 Twin Otter aircraft was grounded due to high winds over the mesa. The Twin Otter carries SWESARR – the Snow Water Equivalent Synthetic Aperture Radar and Radiometer. Developed at NASA Goddard, SWESARR uses active and passive microwave instruments to calculate SWE. Its precise measurements require precise flying, and the 50-knot winds were too strong for the plane to collect good data.

“SWESARR’s active instrument transmits a pulse, which penetrates the snowpack, hitting and interacting with all these little snow particles, and bouncing back to the instrument,” said Batu Osmanoglu, a research scientist at NASA Goddard and the principal investigator of the SWESARR team. “The passive side is more like a thermal camera, collecting the natural radiation coming from the snowpack. These two pieces of information are what we use to infer the SWE for a given area.”

The plane also carries CASIE, the Compact Airborne System for Imaging the Environment. CASIE was developed at the University of Washington and collects data on snow surface temperature, which is important for both validating satellite data and improving models of snow’s surface energy balance – the exchange of energy between the snow, the atmosphere and the ground beneath.

Shortly after we arrived, the team convened for a new weather report: The winds had calmed in time for a late afternoon flight. The airport team prepped the plane for flight while the instrument team got SWESARR ready to go.

The DHC-6 Twin Otter carrying the SWESARR and CASIE instruments was grounded in the morning due to high winds, but took off late in the afternoon for one flight over the mesa. Credit: NASA / Jessica Merzdorf
The DHC-6 Twin Otter carrying the SWESARR and CASIE instruments was grounded in the morning due to high winds, but took off late in the afternoon for one flight over the mesa. The team completed all 6 planned SWESARR flights. Credit: NASA / Jessica Merzdorf

After takeoff, it was time for us to take off too: The trip from Montrose to Grand Mesa is just under two hours, and we wanted to reach the lodge before dark. We were hoping for a good night’s rest – after catching up with the airborne team, our next stop was traveling by snowmobile to spend time with the ground team on the mesa.

A Wintry Flight

The NASA P-3 Orion on the runway ready for IMPACTS’ second science flight on Jan. 25, 2020, at NASA’s Wallops Flight Facility in Virginia. Credit: NASA/Katie Jepson
The NASA P-3 Orion on the runway ready for IMPACTS’ second science flight on Jan. 25, 2020, at NASA’s Wallops Flight Facility in Virginia. Credit: NASA/Katie Jepson

By Ellen Gray /NASA’S WALLOPS FLIGHT FACILITY, VIRGINIA/

After a cloudy and rainy morning, by 1:50 pm the sun had come out and the skies were clear for take-off at NASA’s Wallops Flight Facility in Virginia. The P-3 Orion research aircraft outfitted with eleven instruments to measure conditions inside snow clouds was heading north to a storm system over New York and Vermont for the second science flight of the Investigation of Microphysics and Precipitation for Atlantic Coast Threatening Snowstorms, or IMPACTS field campaign.

NASA’s high-flying ER-2 was already in the air. Based out of Hunter Army Air Field in Savannah, Georgia, it had an extra hour to fly so that the two planes—the ER-2 at 60,000 feet and the P-3 starting at 18,000 feet—would arrive at the same time and fly along the same path to make simultaneous measurements.

Three hours before takeoff at Hunter Army Air Field in Savannah, Georgia, ER-2 pilot Cory Bartholomew was helped into his full-pressure suit and breathed pure oxygen to help remove nitrogen from his bloodstream. This process prevents decompression sickness at high-altitudes. Credit: NASA/Katie Stern
Three hours before takeoff at Hunter Army Air Field in Savannah, Georgia, ER-2 pilot Cory Bartholomew was helped into his full-pressure suit and breathed pure oxygen to help remove nitrogen from his bloodstream. This process prevents decompression sickness at high-altitudes. Credit: NASA/Katie Stern

Since we were flying into bad weather, I was worried about a bumpy ride—and we got it. Our flight path led us out over the ocean first to approach Long Island from the south. At thirty minutes after take-off Claire Robinson from NASA’s Langley Research Center prepped the first of two dropsondes to drop from a tube at the back of the plane into the storm over the ocean. A dropsonde is a small instrument package in what looks like a paper-towel roll. It has a parachute and a radio transmitter that sends data on temperature, humidity and wind speed as it falls, giving a vertical profile of the atmosphere from the plane to the ground.

Dropsonde operator Claire Robinson of NASA’s Langley Research Center hangs on to her seat at the back of the plane through turbulence while she waits for us to fly over the drop point. The dropsonde is inside the black tube in the bottom center of the picture. Credit: NASA/Katie Jepson
Dropsonde operator Claire Robinson of NASA’s Langley Research Center hangs on to her seat at the back of the plane through turbulence while she waits for us to fly over the drop point. The dropsonde is inside the black tube in the bottom center of the picture. Credit: NASA/Katie Jepson

While Claire was watching her monitor for the plane to be over the right spot, we hit turbulence that made it feel like we were going over bumps on a roller-coaster. It got bad enough we needed to return to our seats in the ten minutes between the first and second dropsondes. The turbulence evened out fairly quickly though, especially once we were back over land where the upward movement of air was less severe. Bumps returned periodically throughout the flight, but it ended up being smoother overall than expected.

After the dropsondes were away we continued north over Connecticut and western Massachusetts where we turned left to start the first of three bowtie flight patterns, two over southeastern New York and one over Vermont. Bowties are these large triangular patterns that approach the storm from many different angles.

The P-3 flight path is shown in orange. We started out northbound over the ocean and then did the New York bowtie twice, then the Vermont bowtie once before flying home south over Philadelphia. Credit: NASA
The P-3 flight path is shown in orange. We started out northbound over the ocean and then did the New York bowtie twice, then the Vermont bowtie once before flying home south over Philadelphia. Credit: NASA
The ER-2 flight path is shown in yellow on top of the orange P-3 track. For the majority of the flight the two planes were in a “stacked” formation. Credit: NASA
The ER-2 flight path is shown in yellow on top of the orange P-3 track. For the majority of the flight the two planes were in a “stacked” formation. Credit: NASA

“The atmosphere is not a layer cake,” said atmospheric scientist Sandra Yuter from North Carolina State University, when I spoke with her before the flight. She’s in charge of plotting the flight paths to maximize the science measurements based on the forecasts two-days ahead of time, which she then sends to the pilots and aircraft coordinators who will iterate on it to make the final flight plan.

The atmosphere is instead more like a cake with a marbled interior—swirls and wiggly lines sliced one way, large patches and different swirls when sliced another. “We’re not expecting the same cross-sections in different parts of the storm,” Sandra said. “Bowties give you those multiple angles.”

At the top of the first bowtie over New York, we started out at 18,000 feet, high above the freezing level (0°C). (About half-way through we descended to 16,000 feet at the request of Air Traffic Control.) Mike Poellot of the University of North Dakota and today’s Flight Scientist, sitting in the cockpit to coordinate between the science team and the pilots, asked over the headset, “Cloud probes what are you seeing?”

Snowflakes flashed by at Greg Sova’s station as the multiple cloud probes imaged snowflakes, water droplets, and ice as we flew through the cloud. Credit: NASA/Katie Jepson
Snowflakes flashed by at Greg Sova’s station as the multiple cloud probes imaged snowflakes, water droplets, and ice as we flew through the cloud. Credit: NASA/Katie Jepson

In the main cabin, Greg Sova, a grad student at the University of North Dakota and Starboard Wing Instrument Operator, answered the first of many such check-ins. On his monitor, streams of tiny pictures from his instrument scrolled by. The tiny pictures were of cloud, ice, and snow particles, most less than a millimeter big, that had just been imaged at ~300 mph.

On that first pass of the bowtie, he was seeing from the cloud probes, “Columns and dendrites but a lot of shattering.”

Images from the Hawkeye Cloud Particle Imager throughout the Jan. 25 flight. Left—capped columns. Middle—aggregates. Right—small spheres and dendrites. The cloud probes instruments logged 23,651,553 cloud particles during the 5.8-hour flight. Credit: NASA
Images from the Hawkeye Cloud Particle Imager throughout the Jan. 25 flight. Left—capped columns. Middle—aggregates. Right—small spheres and dendrites. The 2D-S cloud probe instrument logged 23,651,553 cloud particles during the 5.8-hour flight. Credit: NASA

Columns and dendrites are types of snow crystals and were also common in later check-ins as we continued on. So were aggregates, a bunch of snowflakes stuck together in a mass, thin needles, and at lower altitude, spheres that were probably water droplets as we did the second bowtie at lower altitude where the air temperature was warmer. Sometimes it was mix of all three. At times it would switch back and forth as we passed through air with different characteristics—remember that marble cake analogy?

At one point on the northern bowtie over Vermont, Greg reported that we’d passed from seeing more liquid droplet spheres to being back in crystals of snowflake plates, dendrites, with a column or two. Then he added, “And as soon as I said that we’re back into small spheres.”

While the P-3 flew through the clouds, the ER-2 paced us from high above with its suite of remote sensing instruments. The two planes were in sync, for the most part passing over the same legs of the bowties less than 5 minutes apart. Each bowtie took about an hour, and a little after 6:00 pm we dropped to 12,000 feet for the flight home, while the storm system continued east.

The view of Philadelphia at night from the cockpit of the P-3 on our way back to Wallops. Credit: NASA/Katie Jepson
The view of Philadelphia at night from the cockpit of the P-3 on our way back to Wallops. Credit: NASA/Katie Jepson

“I think was good mission,” Mike said when we got back. “The instruments seem to work well, aircraft coordination seemed to go well, and we definitely got into some weather. A lot of precipitation down low that was occurring, and I think it was more along the lines of what we’re looking to do in this project.”

In the days that follow, the instrument teams will begin processing the data they collected, while the forecasters look out for the next storm on the horizon.

Meet IMPACTS’ Student Forecasters

Map of freezing levels - the altitude at which the temperature is 0°C in the atmosphere. This is one of the things forecasters look at to find the snow the fly through and keep the plane safe. Credit: NASA
Map of freezing levels – the altitude at which the temperature is 0°C in the atmosphere. This is one of the things forecasters look at to find the snow the fly through and keep the plane safe. Credit: NASA

By Ellen Gray /NASA’S WALLOPS FLIGHT FACILITY, VIRGINIA/

The IMPACTS team is what makes the field campaign happen. Over 200 people are contributing to the project from aircraft crews and managers, to support and logistics staff, to the scientists running the instruments and asking the big questions. They include veteran pilots and mission managers, university and NASA researchers who’ve done field campaigns before, and graduate students on their first campaign.

Field campaigns provide valuable training and perspective in researchers’ early careers. We caught up with three students who are on the rotating roster for the IMPACTS forecasting team. Their responses have been edited for clarity.

Sebastian Harkema is lead forecaster this week, working in IMPACTS Mission Operations Center just off the P-3 hangar at Wallops Flight Facility. Credit: NASA
Sebastian Harkema is lead forecaster this week, working in IMPACTS Mission Operations Center just off the P-3 hangar at Wallops Flight Facility. Credit: NASA

My name is Sebastian Harkema. I’m a first year PhD candidate at the University of Alabama in Huntsville. This is my first field campaign in general so I’m super excited about this. I’m actually studying snowfall so I’m going to be using the IMPACTS data as part of my PhD for the next three years. Specifically, I’m looking at thundersnow, so I’m hoping to use some of the instrumentation to look at that and to understand how lightning and snowfall can be used in nowcasting—predicting heavy snowfall, where the models really have trouble in that near-term period where forecasters really need that information.

Being a forecaster is different. Going from research to being an actual forecaster is kind of challenging. Because when you’re a researcher you’re staring at a TV screen or a monitor all day. For forecasting you’re doing that but it’s in a completely different environment. As for my schedule, showing up at 5:45 am in the morning, having to put a presentation together by 8:45 am and presenting at 9 am, that’s a challenge unto itself, let alone trying to understand what is going on in the atmosphere. So I definitely give a lot of credit to all the forecasters throughout the United States, and the world—Props to you guys! It’s a lot of hard work and I definitely appreciate it a lot more than I did in the past.

Ben Kiel in the IMPACTS Mission Ops Center at Wallops Flight Facility. Credit: NASA
Ben Kiel in the IMPACTS Mission Ops Center at Wallops Flight Facility. Credit: NASA

I’m Ben Kiel and I’m a Masters student at Stonybrook University in New York. With IMPACTS, I’m helping out with storm forecasts, if there are storms to forecast for. It’s been quite a bit of challenge I would have to say. We were hoping for more storms than what we’ve had so far. It’s kind of funny, most people want good weather, we want bad weather.

This one that we’re looking going after Saturday is one where, if the pattern was more active it’s one we wouldn’t prefer to chase because it’s a messy system. There’s a lot of dry air getting into it. It’s a very warm system. There’s going to be a lot of rain. At least there will be snow aloft. There’s certainly things we can learn from snow aloft, because that’s how this rain is forming as it’s staring out as snow and then falling down and then turning into rain. So we’ll take it.

My main focus will not actually be directly related to IMPACTS. I’m actually working with IMPACTS mission scientist Brian Colle, I’ll be doing a project related to machine learning. It’s a different sort of problem, trying to figure out or explain why our weather models are so variable. We’re trying to find better explanations so that we can pinpoint and improve them. So that’s not necessarily directly related to the IMPACTS project but the data that comes from here will probably certainly get ingested into my work as time goes on. All of these projects end up connected in some way that one acts as a validation for the other. We’ll see what happens there. I’m looking forward to it.

Phillip Yeh and Joe Finlon look at forecasts in the IMPACTS Mission Operations Center, at Wallops Flight Facility, Jan 23.
Phillip Yeh and Joe Finlon look at forecasts in the IMPACTS Mission Operations Center at Wallops Flight Facility, Jan 23. Credit: NASA

My name is Phillip Yeh and I grew up in Parsippany, New Jersey, and I’m currently at Stonybrook University as a PhD student. My focus for my PhD project will likely be using the data that we gather from the IMPACTS project to understand these snow bands associated with these snow storms here in the North East.

I am helping with forecasting for the IMPACTS project. So forecasting involves many things. A lot of it involves looking at the weather models and trying to figure out where the storm is going to be, especially in regard to the timing of the storm, in regard to where the rain/snow line is going to set up, and in regard to where we should be flying the plane. This is my first field campaign. I think the biggest thing I’m looking forward to is the opportunity to fly on the P-3 and the second biggest thing is being able to launch weather balloons, which I’ll do when I leave Wallops and go back to Stonybrook where we’re doing that.

I’ve always loved snow ever since I was young, and often times watched as a snow storm runs too far to the south or to the north and just misses us, or occasionally when the snow hits us perfectly, and also seeing how the forecast models may struggle with getting the location of a storm right.

 

Waiting for Good Snow

NASA's P-3 research aircraft will be flying through clouds during IMPACTS to study snow. Credit: Joe Finlan
NASA’s P-3 research aircraft will be flying through clouds during IMPACTS to study snow. Credit: Joe Finlon

By Ellen Gray / NASA’S WALLOPS FLIGHT FACILITY, VIRGINIA/

Nothing to be done.

When your field campaign depends on chasing winter storms you have to wait for the weather to arrive in its own time. For the science team of the Investigation of Microphysics Precipitation for Atlantic Coast-Threatening Snowstorms, or IMPACTS, campaign that means carefully watching the weather forecasts and then making the most of it when it arrives.

IMPACTS is a field campaign all about snow. This week, we’re with the team at NASA’s Wallops Flight Facility in Virginia, where the P-3 research plane is outfitted with instruments ready to fly into winter storms over the next six weeks in order to learn more about how snowstorms behave. A second plane, NASA’s ER-2 based out of Hunter Army Air Field in Savannah, Georgia, for the campaign, will fly high above the clouds with satellite-simulating instruments aboard to measure the snow clouds from above.

One of the big questions is why do snow clouds organize themselves into bands of heavy and light snow fall? The ultimate goal is to improve forecasts of where and how much snow will fall, especially over the densely populated U.S. East Coast where storms are nicknamed “Snowpocalypse” and “Snowmageddon” because of the disruption they can cause.

IMPACTS' 9am weather briefing on Jan 22 where the team discussed the upcoming snowstorm. Credit: NASA/ Katie Jepson
IMPACTS’ 9am weather briefing on Jan 22 where the team discussed the upcoming snowstorm. Credit: NASA/ Katie Jepson

At the daily 9:00 am weather briefing on Wednesday, the team looked at several different weather models – the same ones used by the National Weather Service, the Weather Channel and other forecasters – to find the next storm they want to target.

“High pressure is finally moving out! Whooo!” said Sebastian Harkema, the lead forecaster, to open the briefing.

If you’re familiar with your local weather news, high pressure usually accompanies sunny skies and clear conditions – the opposite of what the science team is looking for. Instead they’re interested in flying into the bad weather. And there’s a developing storm system that will move across Pennsylvania and up toward Massachusetts, New York and Vermont on Saturday and Sunday.

The big question of the day is, do they schedule one flight through it, or two on back-to-back days?

The advantage of flying twice would be more data collected. However, the human factor of flying two days in a row means that between flights is a 12-hour mandatory crew rest, so the timing of the second flight may not be the best time to sample the second part of the storm – and there’s a chance that the snowing part of the storm may have passed by the time they get out there.

The advantage of doing one flight is that the science team can pick the time and place they think will have the best snow.

The other logistical consideration is the mobile team of researchers from the University of Illinois, Champaign-Urbana, who are driving their vehicles on highways and back roads to be below the storm while the P-3 and ER-2 aircraft fly above it. From the ground they are sending up balloon sondes – instruments to measure the temperature and humidity from the ground to the clouds. They’d likely only be able to make one of two locations, since they’d have to drive through the very snow or cold rain the science team was measuring to get to the second spot three states away.

Forecasting the upcoming weather is a one of the most important jobs for planning flights for IMPACTS. Credit: NASA / Katie Jepson
Forecasting the upcoming weather is one of the most important jobs for planning flights for IMPACTS. Credit: NASA / Katie Jepson

In the end, the team waits for the next run of the models, which come out every 6 hours, before making a decision. At the times and locations that look the most promising – Central Pennsylvania, the tri-corner where Massachusetts, New York and Vermont meet – they look at how wet or dry the air is and the likely temperatures, trying to discern the best spots to sample snow.

“It’s a messy storm,” said IMPACTS Principal Investigator Lynn McMurdie of the University of Washington. The temperatures are on the warm side, and there’s indications of tendrils of dry air throughout, which can stop precipitation. It’s unclear in some spots whether they’d find rain or wet snow.

The verdict: one flight on Saturday to pick the best time and place. Three days out, they’re looking at Vermont, but they won’t make any final decisions until they have a better forecast to help narrow the timing and location down in the next day or so. Still, the flight planners are already working up a preliminary plan so they’ll be ready to refine it when conditions become more clear tomorrow.

IceBridge Takes Flight from Down Under

NASA’s Gulfstream GV aircraft is based in Tasmania, Australia this fall for Operation IceBridge flights to East Antarctica. (Credit: Linette Boisvert/NASA)
NASA’s Gulfstream GV aircraft is based in Tasmania, Australia this fall for Operation IceBridge flights to East Antarctica. Credit: Linette Boisvert/NASA

by Kate Ramsayer

Operation IceBridge took off on the first flight of its final polar campaign Thursday, with a route designed to measure the ice in a region of Antarctica the mission had not yet explored.

IceBridge has been gathering data on Arctic and Antarctic ice sheets, glaciers and sea ice for 10 years. It was designed to ‘bridge the gap’ in between the Ice, Cloud and land Elevation Satellite (ICESat), which stopped collecting data in 2009, and ICESat-2, which launched in September 2018. Over the past decade, IceBridge has been based out of airports in Alaska, Greenland, Chile, Argentina and Antarctica – but for this final polar campaign, it has a new base at Hobart in Tasmania, Australia.

The tongue of Antarctica’s Dibble Glacier, as seen from the first flight of IceBridge’s final polar campaign. (Credit: John Sonntag/NASA)
The tongue of Antarctica’s Dibble Glacier, as seen from the first flight of IceBridge’s final polar campaign. Credit: John Sonntag/NASA

With flights from Australia instead of South America, IceBridge is better poised to measure more of East Antarctica, said Brooke Medley, IceBridge deputy project scientist at NASA’s Goddard Space Flight Center. There, the vast store of ice covers an area about the size of the continental United States – and it’s relatively unexplored, compared to West Antarctica and the Antarctic Peninsula.

On Thursday’s flight (that’s Thursday, Australian time, which is late Wednesday/early Thursday in the U.S.), IceBridge flew over the Dibble Glacier and nearby regions of the ice sheet, taking measurements not only of the ice but of the bedrock below. Onboard NASA’s Gulfstream GV aircraft are multiple instruments, including two versions of the Airborne Topographic Mapper (a laser altimeter to measure ice height), the Multichannel Coherent Radar Depth Sounder (MCoRDS), a gravimeter and several other instruments.

Future flights will take measurements of additional glaciers and sections of the ice sheet, as well as sea ice. With ICESat-2 in orbit, IceBridge will also fly along some of the satellite’s orbital paths, to measure the same stretch of ice and help ensure the year-old satellite’s data is accurate.

The marginal ice zone in the Southern Ocean north of Wilkes Land Credit: John Sonntag/NASA
The marginal ice zone in the Southern Ocean north of Wilkes Land Credit: John Sonntag/NASA

This campaign is adding another element to the mix — in addition to the airborne and satellite measurements, scientists will be out on the ice taking height and density measurements as well. Researchers can then compare the data from the ground, air and space. Medley, who will be on the ice near Casey Station in Antarctica, said she’s looking forward to waving up at IceBridge as it flies over.

“I’m literally getting a new perspective: rather than looking down to the ice from the plane, I’m looking up from the ice to the plane!” she said. “It will be a very special experience.”

 

The New and the Lost World of Hunga Tonga-Hunga Ha’apai

The newly erupted cone (right), and pre-existing Hunga Tonga (to left), with SSV Robert C. Seamans. Credit: NASA
The newly erupted cone (right), and pre-existing Hunga Tonga (to left), with SSV Robert C. Seamans. Credit: NASA/ Dan Slayback

by Dan Slayback, NASA Research Scientist aboard the SSV Robert C. Seamans / KINGDOM OF TONGA /

What a week! Having just finished an expedition to Earth’s newest landmass, Hunga Tonga-Hunga Ha’apai (HTHH) in the Kingdom of Tonga a few days ago, I thought I’d write a few thoughts on this latest expedition to Earth’s newest landmass.

Shortly after the volcanic eruption that constructed this new island began in December 2014, we were alerted at NASA’s Goddard Space Flight Center, in Greenbelt, Maryland, and initiated collection of relevant satellite imagery. Closely following this over the next several months, we observed rapid erosion of the southern coast due to oceanic wave action, at one point breaching the crater wall and opening the crater lake to the sea. Based on observations to this point, we expected a relatively rapid and possibly complete disappearance of the new island, perhaps within months or at most a few years. But instead, the island has held on!

In mid-2018, with the island just over 3 1/2 years old, I was extremely fortunate to be invited to join a leg of the Sea Educational Association’s SEA Semester/SPICE (Sustainability in Polynesian Island Cultures and Ecosystems) program cruise through the southwest Pacific that passes conveniently close to HTHH. That exploratory visit, one year ago, was extremely valuable to let us get our feet wet (figuratively and literally) in understanding the island system from the ground, instead of solely from a satellite vantage point hundreds of miles in space. We made many useful observations, collected some good data, and gained a more practical human-scale understanding of the topography of the place (such as that the adjacent pre-existing islands, and their rocky shorelines, are almost fortress-like in their inaccessibility). We also saw things not accessible from space, such as the hundreds of nesting sooty terns, and details of the emergent vegetation.

My return this year was to extend and improve the observations we made last year, and to lay the groundwork for continued and new observations into the future. A significant advantage of traveling with SEA is the small army of 26 energetic undergraduates on board the ship, willing and able to help accomplish a wide variety of tasks we set for ourselves; without their help, much of what we accomplished would simply not have been feasible.

Sooty tern soaring in front of Hunga Tonga; Hunga. Credit: NASA
Sooty tern soaring in front of Hunga Tonga; Hunga. Credit: NASA/ Dan Slayback

The core goal of these field expeditions is to improve our understanding of the island’s brief evolutionary history and likely future. The island was formed by a surtseyan eruption, which is a relatively modest explosive eruption (compared to say, Mt St Helens or Mt Pinatubo) occurring in shallow waters. They are relatively common along the active Tonga trench (just over the past few days here, a smoke eruption has been reported further north in Tonga, sending plumes over 15,000 feet into the sky, and a magnitude 5.2 earthquake was reported to the east). But it is less common for such eruptions to construct stable landmasses that survive for more than a few months.

Over the past century, only two other surtseyan events have resulted in lasting edifices: Surtsey island in Iceland (erupted in the late 1960s; the type event), and Capelinhos on Faial in the Azores (mid/late 1950s). In Tonga, there are several examples of such eruptions forming short-lived islands over the past century, with the most recent erupting from the same submarine caldera as HTHH in 2009, only 1-2 km from the current cone; it washed away within half a year or so. The current cone may be persisting perhaps due to a larger volume of material ejected (giving it more time to stabilize before the oceanic wave action and pluvial (rain-caused) erosion erode it away), or perhaps its position between the pre-existing islands has provided a level of protection against oceanic wave erosion.

In any case, the appearance of a new landmass (approximately 190 hectacres or 475 acres in size) has presented the unique and rare opportunity to study a rapidly evolving landscape from space, while observable change is occurring over relatively short periods of time (months to years). One key question to understanding its erosional past and future is to better estimate where erosion is occurring, at what rates, and to isolate pluvial-based gully erosion of the flanks from oceanic wave abrasion of sea-cliffs.

Back home at Goddard Space Flight Center in Maryland, we have been using high resolution stereo satellite imagery to provide one estimate of this, but the extreme relief (gullies and canyons with sheer walls up to 30 meters high) is difficult to accurately resolve with standard space-based stereo pair imagery. Thus, we deployed small commercial drones during our field visit to map the entire island at greater than 10-times the resolution of even the best commercial satellites. With more time and cooperative weather, we could have flown lower and achieved even finer resolution, but we did not want to risk flying the drone to a watery grave in questionable weather. The drone imagery will be processed using structure from motion (SfM) techniques that are better able to resolve the high relief topography than we can achieve with simple stereo pairs.  We collected such imagery last year as well, so when processing and analysis is complete, we will have useful estimates for the quantity of erosion occurring in different regions, and from different processes (rainfall vs oceanic wave abrasion). As we also installed a precipitation gauge on this expedition, in the future we will be able to quantitatively model observed erosion as a function of rainfall amounts and rates.

Hunga Tonga from deep gully on new cone. Credit: NASA
Hunga Tonga from deep gully on new cone. Credit: NASA/ Dan Slayback

The other key question about the island’s future is whether a hydrochemical process termed palagonitization is, in the presence of heat and water, cementing the layers of ash into a much more durable substance, termed palagonite. If the core of the cone is slowly cooking into palagonite, it will be much more likely to resist erosional forces for many decades or longer. If this process is not occurring, then the observed erosional forces may reduce the island to little more than a shoal in a couple of decades.

During our visits, we have collected small fragments of palagonite-looking minerals (lab analysis is needed to confirm), and areas exposed along the southern cliffs (where the rate of oceanic wave erosion is significant) visibly resemble exposed palagonitized zones on Capelinhos and Surtsey. A key finding from this expedition included areas of substantial subsurface heat, detected along the shore of the crater lake at depths from the surface to less than a meter. We had hoped to find cracks venting hot gases in places, and brought along an infrared camera to help detect such, but in the end, a student literally stumbled across this sub-surface heat. While handling a small raft (deployed for sonar analysis of the crater lake bottom), her legs plunged through the soft sediment at the edge of the lake to a depth of a few feet, and found unusually warm pockets. We confirmed temperatures of 100-130F in several zones around the lake, simply by pulling up the sediment by hand.  In any case, this suggests residual heat is circulating near the surface, and therefore may well be doing so within the core of the cone, establishing a critical condition for the formation of palagonite.

Along with helping to answer these key questions, our visit facilitated exploration of other important facets of the island’s evolution, including: bathymetric surveys of the crater lake and coastal shallows; surveys of the flora and fauna; and surveys of and collection of accumulated garbage.

Tern soaring near Hunga Tonga. Credit: NASA
Tern soaring near Hunga Tonga. Credit: NASA/ Dan Slayback

One change that I found particularly striking from one year ago was the development of the vegetation establishing itself on the new land.  In 2018, there were three primary patches of vegetation: two in depositional areas to the northwest and southwest of the cone (near the pre-existing Hunga Ha’apai island), and one on the western flank of the cone itself. Last year, the northwest patch was heavily dominated by near mono-culture of beach morning glory, but this year was host to a much more diverse assemblage of plants (including morning glory, but no longer dominated by it). Conversely, the patch on the western flank of the cone appeared less diverse than last year. However, last year it hosted a boisterous colony of nesting sooty terns, while this year there were no birds present.

Which highlights another major change – the distribution of bird life on the island system. Last year we found nesting sooty terns in two large aggregations numbering likely 1000 birds or more in total in the center and west of the system. This year, however, those areas were entirely unused by the terns, while a smaller nesting colony was found far to the east, abutting the pre-existing Hunga Tonga edifice. We also observed rats and owls, and thus suspect there may be more complex ecological interactions at play here (the terns nest on the ground). However, other bird species were more prevalent, including species not seen last year such as red-footed boobies, tropicbirds, and a good number of petrels and shearwaters. We also saw a much larger number of frigate birds (both ‘lesser’ and ‘greater’ species), than the few observed last year. Although we had a dedicated observer to survey birds (and plants) which helped substantially with bird identification (and relieved the pressure to do this myself, personally imposed as an amateur birder), it was still obvious to me that more species, and more individuals of more species (except the sooty terns), were present this year.

Frigatebird soaring over Hunga Tonga. Credit: NASA
Frigatebird soaring over Hunga Tonga. Credit: NASA/Dan Slayback

The bird life was particularly active around Hunga Tonga, which appears cut from an exotic island adventure film: mostly sheer cliffs rise up to over 400 feet, facing the black volcanic cone (which you could readily imagine emitting a column of smoke), and draped in thick tropical greenery. At Hunga Tonga’s flat top, which appears entirely inaccessible without climbing gear, tropical trees and palms sway in the wind, while scores of brown boobies, noddys, frigatebirds, and tropicbirds soar and call. With the overhead avian cacophony providing the soundtrack, the scene of a lost tropical paradise juxtaposed against the new, somber and foreboding cone of the crater suggests a primeval landscape from a different age.

– Dan Slayback, Research Scientist with Science Systems and Applications, Inc., at NASA’s Goddard Space Flight Center