NASA Earth Expeditions – Your planet is changing. We’re on it from land, sea, and air.

Pandemic Delays, But Doesn’t Slow, Ice Melt Research in Greenland

A bit of snow fell before the DC-3 plane took off for another day of dropping probes into the waters around Greenland. Credit: Josh Willis/JPL

By Lara Streiff

Despite racing against impending harsh weather conditions, a red and white World War II aircraft flew slowly and steadily over the icy waters surrounding Greenland in August and September. Three weeks delayed by pandemic restrictions, scientists from NASA’s Jet Propulsion Laboratory inside this retrofitted DC-3 plane started dropping hundreds of probes as part of an annual expedition known as the Oceans Melting Greenland (OMG) Project.

Since 2016, the OMG project has conducted numerous flights over the waters near Greenland’s lengthy and jagged coastline. They drop roughly 250 probes each year (though they managed a record 346 during this extraordinary 2020 expedition) which then relay temperature and salinity data. The team uses this information to help determine how much the surrounding ocean is contributing to Greenland’s ice melt.

“The glaciers are reacting very strongly to the ocean and we ignore that at our peril,” said JPL scientist and principal investigator Josh Willis. “The oceans have the potential to melt the ice very quickly and drive the sea level rise even higher than we expected.”

If it all melted, Greenland’s ice could contribute as much as 25 feet of sea level rise—though Willis assures us that this is not expected within the next year, or even the next 100 years. The big question that his team is trying to help answer is rather the speed at which the ice is melting.

In the northwest of Greenland, where the Upernavik glacier meets the Atlantic. Credit: Josh Willis/JPL

Unlike icebergs—which float in water—glaciers sit atop a land mass, seemingly exposed and vulnerable to the warming atmosphere. While the atmosphere is a significant factor, it is not solely responsible for glacial melt. As the glaciers in Greenland start to ooze off the island in massive rivers of ice, they carve fjords into the landscape until they finally connect with the sea. While surface waters are generally frigid, the warmer ocean waters from below can cause the glacier to melt more quickly and speed up the amount of ice that drains off the land into the ocean.

Though the coronavirus pandemic had sweeping impacts across the globe, it didn’t halt environmental processes like Greenland’s glacial ice melt. It also didn’t impede the resolve of the OMG scientists to continue their work.

Starting in March up until the day they landed in Greenland on August 24, Willis says he wasn’t sure they would be able to collect their data this year. But cooperation between the various stakeholders, including NASA, the State Department, and the governments of Canada and Greenland, was key. Willis also gives credit to a huge amount of hard work by OMG’s Project Manager, Ian McCubbin of JPL, for making it possible. “If it wasn’t for McCubbin,” said Willis, “we’d still be sitting on our couches.”

Coordinating the scientists and equipment necessary for any expedition requires a great deal of planning, and the additional pandemic-related precautions made everything just a little bit more complicated.

“It was like a whole new layer, after you go across the border and go through customs and boarder control, now you also go through coronavirus screening,” Willis said.

Oceans Melting Greenland lead scientist Josh Willis getting tested for COVID-19 while in Greenland. Credit: Josh Willis/JPL

In addition to getting tested a whopping seven times, two of which took place before even stepping foot in Greenland, Willis and the other members of the OMG team were very cautious. There was an initial isolation period after landing on the island during which they could fortunately work on the plane and equipment preparation, wearing masks when traveling to and from the site and no contact with locals. Greenland has had very few cases of COVID, and doesn’t have enough hospitals to handle any outbreaks, so the team was especially conscious of limiting their interactions with people there.

One exception was communicating with the nurses conducting their COVID-19 tests. “It was quite an experience getting tested this many times,” said Willis, “but the most fun was actually with nurses in Greenland, who were very nice and asked about our mission, so we got to tell them about what OMG was doing—and I suspect they followed along the rest of our journey on social media.”

Though some legs of the scientists’ expedition were delayed or more challenging as a result, Willis says it was well worth the extra effort to ensure everyone’s safety.

The outcome turned out to be a banner year for the project, despite the late start. Instead of heading north at the beginning of the month, it was already well into August when Project Manager Ian McCubbin and the three scientists from JPL—Ian Fenty, Mike Wood, and Willis himself—were able to meet with their flight crew from Kenn Borek Air.

The crew after their successful season. In the photo from left to right: Josh Willis, OMG lead scientist; Mike Wood, OMG scientist; Linden Hoover, Kenn Borek co-pilot; Jim Haffey, Kenn Borek pilot; and Ian Fenty, OMG scientist. Not pictured are Gerald Cirtwell, Kenn Borek flight engineer, and Ian McCubbin, OMG project manager. Credit: Josh Willis/JPL

Once they were on the ground in Greenland, their main concern was for the conditions they might encounter once back in the air.

“Weather starts to get pretty rough in September, and very rough in October.” said Willis. Fortunately, they were able wrap up their surveys by mid-September, mostly dodging the snow, sleet and wind that might impede their ability to drop all of the probes. “It was a sprint to the finish line, but we were able to accomplish everything we wanted to do and more.”

In fact, the team encountered unusually good conditions in the north east parts of the island, where ice and fog usually prevent access. As a result, they measured some glaciers that had never been sampled before.

When the project first began in 2016, the scientists also flew a jet with a radar strapped on the bottom to measure big swaths of glaciers from above, but NASA’s ICESat-2, an Earth-observing satellite that measures the mass of ice sheets and glaciers down to the inch that launched in 2018, takes care of that part of the mission now.

More than 45 scientific papers have now been published based on OMG data, with several more in progress. Willis says that every new discovery reminds them that the oceans are more important than they ever thought possible.

This year they noted new observations of Greenland’s largest glacier Jakobshavn, which has been closely monitored since the start of the project in 2016. In the first couple of years, the water near Jakobshavn cooled by 2.7 degrees Fahrenheit (1.5 degrees C)—a whole lot for a block of ice according to Willis. That cooling slowed the melting of the glacier, which then started growing instead. But early this year warm water returned to Jakobshavn and the recent observations suggest it is now thinning once again.

The view of Greenland’s Jakobshavn glacier from the DC-3 plane which carries the Oceans Melting Greenland Project scientists Credit: Josh Willis/JPL — The view of Greenland’s Jakobshavn glacier from the DC-3 plane which carries the Oceans Melting Greenland Project scientists. Credit: Josh Willis/JPL

These continued discoveries from the project are very exciting for the scientists and organizations involved. Because of this, the OMG project has gotten approval to continue its research beyond the original end date, meaning that Willis and his crew will again be making their way back to Greenland next August, and this time hopefully without much delay.

ACTIVATE Makes a Careful Return to Flight

Masks are part of the safety protocol for ACTIVATE scientists. Here, Yonghoon Choi prepares for a science flight on the HU-25 Falcon. Credits: NASA/David C. Bowman

By Joe Atkinson / NASA’s Langley Research Center, Hampton, Virginia/

Four months ago, with COVID-19 disrupting life across the globe, it seemed virtually unthinkable that a major NASA airborne science campaign would fly again anytime soon.

But today, that’s exactly what’s happening.

In August, NASA’s Aerosol Cloud Meteorology Interactions Over the Western Atlantic Experiment (ACTIVATE) eased into its second set of 2020 science flights out of NASA’s Langley Research Center in Hampton, Virginia. Barring any threats to the health or safety of the researchers or crew, flights will continue through the end of September.

Those flights are taking scientists over the western Atlantic Ocean to study how atmospheric aerosols and meteorological processes affect cloud properties. In addition, modelers will use data from these flights to better characterize how the clouds themselves, in turn, affect aerosol particle properties and the amount of time they spend in the atmosphere, as well as the meteorological environment. Coordinated flights between a King Air and an HU-25 Falcon allow researchers to fly above, below and through the clouds with a suite of instruments that can take measurements remotely, or from the air around the aircraft.

The HU-25 Falcon sits on the tarmac just ahead of a flight. Credits: NASA/David C. Bowman

“The data have been really good so far,” Armin Sorooshian, ACTIVATE principal investigator and an atmospheric scientist at the University of Arizona, said of the summer flights. “We’ve seen some interesting features, like smoke from the wildfires on the West Coast.”

That smoke can seed clouds over the Atlantic Ocean.

Sorooshian is leading the campaign remotely from his home in Tucson, Arizona, where he and his wife are juggling work and the care of two children — a two-year-old boy and a baby girl who was born in July.

He admits it’s “a little tough.” But in a world where these flights could have been scrubbed from the calendar completely, Sorooshian isn’t interested in dwelling on the negatives.

“They’re good problems,” he said.

Good Problems

The ACTIVATE team began the first of two planned 2020 flight campaigns in February. They completed most of those flights, but had to pull the plug a little early in mid-March when concerns about the spread of COVID-19 began to sweep across the U.S. At that point, the fate of the second set of flights, originally scheduled for May and June, was — pardon the pun — very much up in the air.

As the COVID situation evolved, though, and as Langley leadership began to admit a limited number of research projects back on center with stringent safety protocols in place, it became clear there might be a glimmer of hope for ACTIVATE.

ACTIVATE is uniquely positioned among other current NASA airborne science missions because it’s based out of a NASA center, and the flight crew and many members of the science team are also based out of that center. John Hair, ACTIVATE project scientist with Langley’s Science Directorate, knew that from a purely logistical perspective, the mission could return to flight without the need for anyone to travel in from out of town.

“We had an opportunity because ACTIVATE has a relatively small crew that can operate the instruments in the aircraft, and do that, we felt, safely — albeit with some changes to the initial plans we set out,” he said.

Besides obvious stuff such as wearing masks and being mindful of social distancing, those changes include conducting the various daily flight planning meetings and pre-flight briefings completely via video conference. Researchers are also doing real-time monitoring of flight data from their homes. For researchers who are flying or need to be on center, the project has found ways to streamline some processes.

“For example, people are learning how to do their calibrations at the end of the flight after the instruments are already warmed up,” said Hair. “And then it only takes an hour to do.”

Compare that to the three or four hours it can take a researcher to warm up and calibrate an instrument before a flight.

The King Air rolls out of the hangar before a science flight. Credits: NASA/David C. Bowman

The entire operation has taken a lot of careful planning and coordination between Langley’s Science Directorate, Research Services Directorate and Center Operations Directorate. Sheer determination has certainly played a role as well.

“We all signed up for supporting research as it comes in. ACTIVATE was in the middle of a major campaign and we wanted to get them back to flying as soon as we could,” said Taylor Thorson, ACTIVATE project pilot with Langley’s Research Services Directorate.

Sorooshian believes this experience could be instructive for the next round of flights, which are currently scheduled to kick off in February 2021 when COVID-19 could still be a significant concern.

It’s not just instructive from a safety perspective. Marine clouds are more scattered and difficult to forecast in the summer.

“Flying this summer also allows the team to hone the flight planning strategies, which can build upon heading into the next two years of flight campaigns,” he said.

For now, he and Hair are just happy to see a study they both care deeply about back in action.

“This is exciting that we’re out doing some flights,” said Hair. “People are excited to get the critical science data that we’re collecting on these flights.”

The ACTIVATE science team includes researchers from NASA, the National Institute of Aerospace, universities, Brookhaven National Laboratory, Pacific Northwest National Laboratory, the National Center for Atmospheric Research and the German Aerospace Center. The current flight campaign is the second of two in 2020, with two more to follow in 2021, and another two in 2022.

ACTIVATE is one of five new NASA Earth Venture campaigns originally scheduled to take to the field in 2020. Three of the five have been postponed due to COVID-19. To learn more about the other campaigns, visit: https://www.nasa.gov/feature/goddard/2019/nasa-embarks-on-us-cross-country-expeditions

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

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

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

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

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

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

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

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: 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.

Operation IceBridge: Glaciers Aren’t Forever

by Emily Fischer

Flying a plane over Alaska’s vast landscape provides a birds-eye view of some incredible sights. Bears run across frigid streams, moose trample through mounds of snow, and golden eagles own the air above ice-capped mountains. Glaciers cut paths through these mountains, leaving lakes and rivers in their wake. These glaciers are especially interesting to scientists who want to learn more about climate change in a region that is changing more than any other.

Johns Hopkins Glacier lies beyond Johns Hopkins Fjord. Credits: University of Alaska Fairbanks/Christopher Larsen

According to Christopher Larsen, project manager of Operation IceBridge (OIB) Alaska, these glaciers are losing on the order of 75 billion tons of ice each year, which contribute to global sea level rise. Learning more about these mysterious, ancient ice formations could give scientists a better understanding about the impacts of global climate change in the Arctic.

Thousands of miles above the surface of these glaciers, satellites collect data on how these gargantuan slabs of ice are changing. Ice, Cloud and land Elevation Satellite-2 (ICESat-2) was launched in 2018, 11 years after its predecessor was decommissioned. In the decade in between, OIB bridged the gap, collecting data and exploring Alaskan glaciers with a whole new perspective.

Now, two years after ICESat-2 made its way into low-Earth orbit, OIB is finishing its final campaign. Having wrapped up its flight season last week, the team plans to do a final set of flights in August. And Larsen, a research professor at the University of Alaska Fairbanks, will finish up his last of eleven summers managing OIB Alaska.

A view from the wing of the Cessna TU206G while mapping a potential landslide in the Barry Arm and approaching the Barry Glacier. Credits: University of Alaska Fairbanks/John W. Holt

Instead of satellites, his team collects data using instruments aboard two small, single-engine aircraft. They shoot a laser from the bottom of each plane that hits the glacier’s surface and bounces back up. By calculating the amount of time it takes the laser pulses to return to the instruments, Larsen and his team can then estimate the surface elevation of the glacier at specific coordinates.

He said that most science projects at the university only last three years, but IceBridge Alaska has studied glaciers for over a decade.

“I’ve been involved in almost all of the flight campaigns myself,” Larsen said. “It’s really wonderful to have something that’s dedicated to monitoring and observing glaciers over a longer time period.”

Alaskan glaciers are temperate, meaning the ice is at or near melting point, and they melt and refreeze as they adjust to changes in the climate to maintain a balance between ice accumulation and melting. As the Arctic is warming at twice the global average, ice loss is accelerating, contributing to global sea level rise.

One problem with studying temperate glaciers is measuring depth. Radar doesn’t permeate water well, so determining ice thickness can be a challenge. To resolve this problem, the team must use a different frequency range, which isn’t always 100% effective. Despite this challenge, Larsen and his team have determined that some of the thickest ice in Alaska is on the order of 4,900 feet (1500 meters) and located in the Bagley Ice Valley. If all of that ice were to melt, the whole valley could turn into a lake or fjord.

But predictions of ice melt are hard to make because of the individual nature of glaciers. Like snowflakes, all are unique and respond differently to changes in the environment. “What we’ve found in general is that there’s a lot of variation from glacier to glacier, and it’s hard to pin that to any [common] characteristic of a glacier,” Larsen summarized.

And these glaciers have lost a lot of ice.

Terminus of the Ellsworth Glacier, showing large ice bergs breaking off from the glacier as it retreats. Credits: University of Alaska Fairbanks/Christopher Larsen

Not only are scientific barriers a challenge – physical limitations affect the flight campaign as well. For instance, the weather plays a huge role in the operation’s success. Larsen and his team check the weather constantly and plan their flights a day or two in advance based on wind and storm patterns. Weather is the true determinant of where and when they can fly. While satellites collect data at set intervals, planes that rely on clear and calm skies don’t always have this luxury.

The greatest challenge, according to Larsen, is collecting measurements of the same glaciers at consistent intervals. “And that’s driven mainly because you’re operating a light aircraft in large mountains with big weather systems,” he explained.

Nevertheless, the IceBridge Alaska campaign has been able to successfully collect data by running a relatively small campaign with a flexible team. Their pilots sometimes have to change survey paths mid-flight due to the weather, and research teams work proactively to prioritize safety and efficiency. Adding a new plane this summer has boosted productivity exponentially.

Besides their successful data collection on Alaskan glaciers, the IceBridge team has combined scientific processes with personal observations, some of which have been peculiar, to say the least.

Case in point: While flying over Yakutat Glacier, on the Gulf of Alaska’s coast, Larsen was surprised to see that the glacier was almost entirely concealed by a dark mass. When the plane flew closer, he realized that the ice was actually covered by many fuzzy moss balls, fondly nicknamed “glacier mice” by researchers. These tumbleweeds of Alaskan glaciers are still a mystery to scientists who track their movements. Larsen has seen Yakutat Glacier break apart into large icebergs and retreat significantly over the past few years. Most of the moss balls have ended up in Harlequin Lake.

Fuzzy moss balls, nicknamed glacier mice, gather in piles on Yakutat Glacier. Scientists have observed these moss balls change position over time, but the nature behind this movement is still largely a mystery. Credits: University of Alaska Fairbanks/Christopher Larsen

Lasers and Bubbles: Solving the Arctic’s Methane Puzzle

Phil Hanke (left) and Katey Walter Anthony determine if an Alaskan lake contains methane by igniting the gas flux. Credits: University of Alaska Fairbanks/Nicholas Hasson

by Emily Fischer

Trudging through snow up to their thighs, researchers Nicholas Hasson and Phil Hanke pull 200 pounds of equipment through boreal terrain near Fairbanks, Alaska. Once they reach their destination – a frozen, collapsing lake — they drill through two feet of ice to access frigid water containing copious amounts of methane.

Hasson lies flat on his stomach and reaches both of his arms into the subzero water. The stench of 40,000-year-old rotting vegetation floats up from the permafrost. He attempts to open the valve on a piece of equipment underneath the water’s surface using his fingers, but his thick protective gloves (water would instantly freeze onto his arms, otherwise) make simple tasks challenging. Finally, he manages to collect his sample, close the valve, and put a stopper in the vial, which is now full of methane gas.

The researchers then trek back to their lab to analyze these samples as part of ongoing field research to fill in a key knowledge gap in climate science: What happens to thawing permafrost in winter?

Hasson, a student researcher with NASA’s Arctic Boreal Vulnerability Experiment, or ABoVE, has been studying Alaskan lakes for three years. His team at the University of Alaska Fairbanks researches how thawing permafrost in Arctic regions contributes to climate change.

Permafrost is ground in mainly polar regions that stays frozen throughout the year, for multiple years. Almost 25% of the Northern Hemisphere contains permafrost. Partially decayed plant matter is trapped within the permafrost, creating a sort of “dirty, dusty, carbon-rich” layer of icy soil, as Hasson described.

Permafrost, he continued in analogy, is like a giant carbon freezer that has been storing organic material for tens of thousands of years. Over the past several decades, as climate change warmed the region, it’s as if someone has left the door open and all the contents of the freezer are thawing. As permafrost thaws, trapped plant matter is broken down by microbes; as a result, carbon dioxide and methane—a greenhouse gas 25 times more potent than the former—are released into the atmosphere.

Thawing permafrost can also collapse, creating depressions that fill with rain and melting snow to form thermokarst lakes, accelerating permafrost thaw and the subsequent release of greenhouse gases.

Methane bubbles freeze in the ice as they leak from thawing permafrost beneath Alaskan lakes. These bubbles are measured by researchers to determine the amount of methane released. Credits: University of Alaska Fairbanks/Nicholas Hasso

As the methane bubbles to the surface of lakes in the winter, it freezes in the ice, forming pockets of varying sizes and shapes. These pockets create unique patterns on top of the frozen lakes. In the summer, visitors can watch little bubbles burst at the water’s surface like a hot spring, releasing methane into the atmosphere. This scene illustrates how much the environment here has changed in a region warming twice as fast as the rest of the planet. Only a few decades ago, Arctic winters were colder, many of these lakes didn’t exist and the permafrost was rock solid.

How permafrost behaves in winter has largely been a mystery, but basic physics tells us there’s a lot to learn about its behavior during those darker months. For instance, heat travels slowly through water, so the water in Alaskan lakes holds heat and thaws permafrost partway into the cold season. It’s like lying on the beach in the sun and then walking into an air-conditioned building: your skin still feels warm for a while. Scientists can’t get the whole picture on methane emissions unless they take consistent measurements year-round.

Methane bubbles freeze in the ice as they leak from thawing permafrost beneath Alaskan lakes. Credits: University of Alaska Fairbanks/Nicholas Hasson

Because planes can only take airborne methane measurements in the summer when there isn’t much snow coverage and because field researchers don’t usually take mid-winter measurements, there is an eight-month gap in the data set – eight months that could completely change how scientists model methane emissions, which have nearly tripled in the past 200 years. These models are crucial in understanding methane’s role in climate change. And that’s why Hasson and his colleagues are in the middle of the Alaskan wilderness: to study methane emissions year-round and provide data for developing climate models.

Hasson and Finke’s university lab will age the gas samples they collect in the field using carbon isotopes to better understand how ancient carbon is being transported into the atmosphere. Even now, in the summertime when airborne measurements are possible, the field team still collects samples at thermokarst lakes and takes them to the lab for analysis.

Hasson said a combination of many different types of measurements and methods is vital to their success. The ABoVE team uses absorption spectrometry to measure methane emissions by shooting lasers through large chambers placed in the water. They also use an insulated sled nicknamed “the coffin” to protect their delicate equipment from the cold while traveling in the field. The team even carries around a giant magnet that can image the ground layers below them, mapping thawing regions of the permafrost. All these methods are the pieces to understanding the puzzle of Arctic permafrost.

Field researchers make observations and collect data so that others can put the pieces in computer models and see the greater picture. “I don’t actually make the predictions,” Hasson said. “I’m just gathering the evidence so that people can put the puzzle together and try to figure out what’s going to happen.”

ABoVE field researchers must navigate rough boreal terrain on foot or by dog sled to access remote permafrost lakes, pulling 200 pounds of scientific equipment behind them. Credits: University of Alaska Fairbanks/Nicholas Hasson

But “just” gathering the evidence underestimates the task at hand. Even in the cold, Hasson must walk hours to each remote Alaskan lake, pulling his equipment along, following densely forested trails that are too narrow for snow machines.

To save time in a season when daylight is limited and the cold unbearable, Hasson and Hanke, an ABoVE research technician, had the idea to use Hanke’s sled dogs for field travel. The dogs are used to running through winding trails and rough terrain while pulling heavy cargo. And this way, the two researchers get a much-needed break from hauling equipment.

“What’s unique is that [dog mushing’s] original intent was to supply healthcare to remote places in Alaska,” Hasson said. “And now, a century later, we’re staying true to that philosophy and collecting long-term data to know the health of our ecosystems.”

Phil Hanke (left) and Nicholas Hasson measure methane seeps from a permafrost lake near Fairbanks, Alaska, using equipment hauled on an insulated sled, nicknamed “the coffin.” Credits: University of Alaska Fairbanks/Nicholas Hasson

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

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

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

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

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

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

A Breathtaking View – Literally

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

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

“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 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

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

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

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

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 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

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

“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.