Notes from the Field

May 25, 2024

Some 25 of us were up before 6 a.m. to head out on the bus from the hotel to Burlington International Airport to catch the C-130 aircraft, a military transport plane repurposed for NASA fieldwork, to begin our 7-hour flight to Pituffik.

Several mountains of baggage, including scientific instruments and personal luggage, separate us from the less-well-heated economy cabin, which was probably reserved for graduate students, though we are far too collegial a group to check seat assignments. As we head north and east, the landscape out the window is vast, entirely gray-scale, and unforgiving: sea ice with streaks and patches of open water as far as one can see in every direction.

About halfway through the flight, we cross the Arctic Circle. Here the scene is often reduced to pure gray, and one cannot tell what is sea ice, snow, or cloud. This is the challenge we have long faced when attempting to interpret our remote sensing imagery; now, as an early gift of the expedition, I experience it directly.

May 26, 2024

The site is halfway between Washington and Moscow. Most or all of the buildings were prefabricated, brought here by ship in the summer, and mounted on stilts due to the permafrost. Some rough grasses are the only apparent vegetation.

In some ways, the base is well appointed. There is a sports center with an abundance of every conceivable exercise machine, also a tanning machine and a perpetual pool, a huge gym, and a yoga room. There is a recreation center with a movie theater, a lounge area with free apples, tea, and coffee, a game room that is more like an arcade with multiple video machines, and a craft center that has sewing machines (including a state-of-the-art Serger), rock cutting and polishing machines, computer graphics, and printers.

This is a remote place. The site is protected by a thousand kilometers of ice in nearly all directions, and the only ways to get here are by air or by boat for a couple of months of the year, when the sea is not frozen. With full daylight all day and “night,” the times-of-day are marked only by artificial clocks; the natural ones are essentially absent.

May 27, 2024

This was mostly a flight-planning day, getting ready for the first science flight of the campaign. It turned cold, windy, and snow fell today. This was more like what I expected but didn’t experience during the first two days. But now it is sunny again, around 6 p.m., and near-freezing, so there is still standing water on the roadways, and we are past the season when it is safe to walk on the ice-bound bay. The severe environment calls for some specific adaptations.

For example, the outer doors have latches that seal upward, so a bear pushing down on the handle will be unable to open the door. The walkways are made of open steel grids, so snow and mud will drip through. Boots are to be brushed before entering buildings, and plastic boot covers are provided in an effort to limit the amount of dirt that is tracked in.

I took a late-night walk. It’s daylight anyway, though overcast, windy, cold, and flurrying. Pretty much what I expected here. 

The power went out twice today. Everything goes down, including the internet. I’m trying to keep everything charged, in case it happens again. Today’s weather represents “Condition Alpha” for storm warnings. That means just be on alert, in case things change. Condition Bravo means you cannot go outdoors without a buddy, or drive alone without a radio. Condition Charlie means you can’t walk out at all; there is a base taxi for urgent movement. Condition Delta: shelter in place. 

The pipes are all above-ground because of the freeze-thaw cycle that would destroy the pipes. I guess they must be heated and insulated. They cross the road by going overhead. 

Car and truck engines must be heated to avoid freezing and cracking. So, many of the buildings have power cords hanging out in front to run electric engine-block heaters. I didn’t take the last picture quite at midnight, but the scene doesn’t change much during the night.

I think I mentioned that it is mud season here. This is no joke. The place has a very industrial feel, and the only place to walk is on the mud roads. I’ve heard it will get worse as the mud deepens, and mosquitoes come out. Something to look forward to…

May 28, 2024

We had our first flight with the P3 today, and it was far better than I had expected. There was a rare case of cloud-free atmosphere over sea ice in one area north of Greenland where some buoys had been deployed, which allowed for both surface ice and aerosol characterization. Also, a nearly 3-hour run at ~500 feet captured aerosol properties over open water along the northern part of Baffin Bay. Among our objectives are learning the sources and properties of aerosols in the Arctic, their evolution as they age, and their impact on clouds. Others are especially interested in the properties of sea ice as it melts. So, this gives us a start on those objectives.

May 29, 2024

The wind is a force of nature. Today it has been blowing at something like 40 miles per hour, with gusts considerably higher. It literally takes your breath away—and this is just Condition Alpha. 

Gusts create the sensation of blowing you away. All this under a relatively clear sky, bright sun, just a few clouds. It is somewhat other-worldly to one who has lived a life at lower latitudes. The temperature is only a few degrees below freezing, but the weather today gives new meaning to the term “wind chill.” 

June 1, 2024

Today was an official day off, and in particular, a mental health day for the forecasters. Several of the military folks on the base arranged to take a group of us on a hike over the Greenland Ice Cap. There were 15 of us in five trucks. The trip involved a fair amount of driving on gravel roads in trucks—about half the time driving, half hiking – 5 hours total. The hike itself was about 5 or 6 miles, and we walked around and then on the glacier, though we never did find the Starbucks.

 

In addition to the stark beauty of the rock fields and ice, the sky is unlike anything we normally see at lower latitudes. The surface is cold, and the atmosphere is no colder (and sometimes is even warmer) than the surface, i.e., it is stably stratified—the “warm” air is already up, so there is not a lot of warm air rising and mixing that typically happens when the surface is heated directly by the Sun.

The glaciers have brought an enormous diversity of stones that litter the ground, and every piece of wood here was carried in from somewhere else. There are little clumps of vegetation, just enough to satisfy the appetites of musk oxen. 

So far, I’ve seen Arctic fox (no pictures—they disappeared too quickly), musk ox in the distance, Arctic hare, and snow goose. No polar bears—and no complaints about that. 

June 7, 2024

This evening I took a long walk out to the ice-bound pier… AND I SAW AN OTTER!!!

June 4, 2024

The Arctic foxes are molting. They were very cute when their coats were all white. Now they are losing their winter coats and turning brown. I did see a couple of full white coats, but was too slow to get a photo. 

June 8, 2024

The project rented a van, and ten of us went off to climb the Dundas, that imposing rock feature not far from the base, though to get there without walking on thin ice (here the term is not merely a metaphor), one has to drive about 30 minutes over rocky and sometimes quite steep roads around the frozen bay.

The angle of repose is the angle a pile of dry sand (or salt) will make if you dump a bucket of it on the ground. It is generally steep (depends in part on the grain size and shape of the sand particles). Dundas is about 725 feet high; it appears to be the remnant of a glacial moraine—rock pushed here by an advancing ice sheet at least that high, that remained after the ice melted away. It is loose sand and rock, mostly gravel and cobble-sized. The climb up was, frankly, arduous, as there are not a lot of footholds. 

The first part was steep enough that going on all fours was necessary in places, and the sand and small rocks would slip easily down the slope as one persevered upward. The final part was up a sheer rock wall that was graced, mercifully, with a sturdy rope. My pictures are lacking for the entire traverse, as all my effort went into the climb itself. I did stop part way up the rock wall to check my life insurance policy.

 The view from the top was spectacular, but truthfully, there are so many great vistas in this rugged place that the main reward was accomplishing the ascent itself. 

The way down was similarly fraught, except that below the rock wall, I had pretty much no choice but to slide down bit by bit—the loose surface material would give way at every step. So, on my back, lift up my rear, slide a few feet using my boots to stop, and repeat. There was some interesting vegetation on the slope—tiny plants and lichen, which I did photograph. I’m told that some of these plants can be hundreds of years old. 

In the distance, we saw some dark spots that the binoculars suggested were seals. (Oh, yes—someone here said that my otter from last night was actually a ring seal; not sure that is authoritative, but…).

June 9, 2024

I agreed to join this afternoon’s walk up the edge of the Greenland Ice Sheet. 

The slope is moderate by Dundas standards, and the path is completely snow-covered. The walk up is of course uphill, and a steady wind of 30–40 mph (the katabatic wind), with significantly higher gusts, blows off the ice. This guaranteed that however far we got up the ice sheet, we would certainly be able to make it down, either on foot or airborne.

There were pools of water within ice basins at the base. They look a beautiful shade of blue. We saw this in Alaska as well. I think it must be that ice either absorbs all the longer wavelengths, or it preferentially scatters blue, or both. The optics here are stunning, at least to me. Probably because they are unfamiliar. 

One way painters provide a sense of distance in a painting is with “atmospherics,” that is, they increasingly blur the edges of more distant objects to account for light scattering by atmospheric gas and aerosols. Mountain climbers experience the opposite, in the thinner atmosphere, remote objects are sharper than they would in everyday experience, so more distant objects appear closer than they actually are. This is true here in Greenland as well, though we are not at a very high elevation along the coast. I expect the phenomenon in this case is due to a very clean atmosphere. 

June 11, 2024

Today I got to fly on the P-3. Every satellite scientist should be required to take at least one such flight to see what the Earth is really like. We flew across northern Greenland and over sea ice. In the two weeks since the campaign deployment began, the depth of the sea ice, and the snow upon it, both decreased at those buoys (where it was measured), and, of course, most everywhere else as well.

A field campaign is a layered operation. Aircraft flight scientists build, run, and maintain the twenty or so instruments that measure particle composition, gas concentration, cloud properties, surface reflectivity, and upwelling and downwelling energy. They are awake by 4 a.m. to prepare their instruments for flight, worry about power supplies and calibration, then sit on the plane for six or seven hours, noting what they see from their measurements and out the window.

The number of leads (i.e., openings in the ice) has increased in places. We flew at high elevation to survey the area, measure the overall surface topography and reflectance, and sample aerosol layers aloft, then descended to 300 feet above the ice to capture aerosols emanating from the surface. The photos tell an accessible part of the story. The rest must be teased out of the data in the coming months and years. But my ride is over for now—there is an aerosol forecast due tomorrow.

June 12, 2024

It was flurrying this evening, and my walk carried me down toward the pier. But you might be pleased to know, I did not go all the way; several seals have now been seen on the ice at the pier. My otter or seal in the water was the first anyone saw, and although they say it is relatively rare for bears to go near the base, seals are their primary food. I figured, after a long winter hibernation, a bear might not count me as even a light snack, but in consideration that I had already booked my flight home, I turned around before getting very near the water’s edge. 

June 14, 2024

I should say that the food here is okay. Better than I expected. Of course, in such circumstances, it pays to begin with low expectations: hardtack, pemmican, and beef jerky. The cafeteria serves a lot of beef and pork, but there is also chicken, a reasonable salad bar, excellent, fresh bread (the highlight in my opinion), always two of THE three kinds of fruit (apples, oranges, and bananas—so yes, they mix apples and oranges), and of course, Danish, at least in the morning. 

In the evening I took a walk, as usual, and ended up in one of the dozens of prefab buildings on the base, with the suggestive label “Heritage Hall.” The door was not locked, and the lights turned on as you entered each room. The place is a sort of museum, a repository for things discarded from the 1950s and 60s.

They have a computer punch-card machine, a vacuum-tube TV set, and a radar scope you will recognize from science-fiction movies. Also some notebooks with photos of the army’s Camp Tuto (now abandoned—only remnants of the airfield remain) and the presumptive city “Camp Century” they built into the ice in the 1950s. The walls flowed at glacial speed but ultimately collapsed.

Thule base was established in 1951, succeeding three waves of Inuit who inhabited the area, apparently beginning 4,500 years ago. The most recent came around 900 CE, met the Norse about 100 years later, and were moved to a new village 60 miles to the north in 1953. There is even a Life Magazine cover showing ships delivering material to the base in September 1952. 

Ralph Kahn, an emeritus research scientist at NASA’s Goddard Space Flight Center now at the Laboratory for Atmospheric and Space Physics at the University of Colorado Boulder, spent three weeks at Pituffik Space Base in northern Greenland in the summer of 2024. He was one of dozens of scientists who participated in ARCSIX (Arctic Radiation-Cloud Aerosol-Surface Interaction Experiment), a NASA-sponsored field campaign that made detailed observations of clouds and atmospheric particles to better understand the processes that affect the seasonal melting of Arctic sea ice. These excerpts from his emails home to family provide a glimpse of what life was like on one of the world’s most northern scientific outposts in the world. Photos were taken by Kahn or Gary Banzinger, a NASA videographer who also participated in the campaign. Kahn, an atmospheric scientist, worked with colleagues to provide daily aerosol forecasts that were used to help plan flights.

Under the Ash: Glacier Science at a Volcano

August 22nd, 2024 by Caela Barry, NASA's Goddard Space Flight Center

Hello from the Goddard Instrument Field Team! Earlier this summer, we visited Katmai National Park as guest researchers. These are some of our photos and notes from the field.

In June 1912, the largest volcanic eruption of the 20th century blanketed glaciers with ash in what’s now known as the Valley of Ten Thousand Smokes. Our 2024 expedition took us deep into the valley, seeking answers about icy volcanic landscapes on Earth, Mars, and beyond. The data and samples we gathered here will help us understand how these buried glaciers and the volcanic deposits on top are evolving over time.

Into the Valley of Ten Thousand Smokes

How do you pack for nine days of hiking and camping in bear territory? Carefully! We secured food and scented items in bear-proof canisters, mapped out tent placements to fit within the perimeter of a portable bear fence, and worked closely with Katmai National Park to minimize our impact while in the backcountry.

Patrick Whelley and Cherie Achilles prepare to hike into the Valley of Ten Thousand Smokes; Aditi Pandey and Alexandra Matiella Novak discuss bear safety with a Katmai National Park Ranger; Whelley walks away from a rendezvous with a helicopter; Alice Baldridge, Pandey, Whelley, David Hollibaugh Baker, Emileigh Shoemaker, Heather Graham, and Andrew Johnson work on setting up base camp.

The journey from Anchorage to our base camp near Knife Creek included flights on tiny aircraft, “Bear School,” a school bus equipped to ford rivers, and a sixteen-mile hike complete with more water crossings and high winds. On day two in the field, a helicopter carrying large items, such as heavy science gear and a group water filter, reached the valley. In case weather prevented the airdrop, we were ready to complete some key tasks using just what we carried on our backs, but we were glad to see the equipment arrive.

Studying Buried Glaciers

In the field, we worked on and around glaciers covered in huge piles of ashy debris. Some team members used ground penetrating radar (GPR) to scan subsurface structures from above. Together with drill coring, hand-dug pits, and a soil moisture probe, GPR gives us insight into what’s going on underground.

Emileigh Shoemaker sets up a ground penetrating radar system; Andrew Johnson measures the distance to a glacier cliff with a laser range finder; Patrick Whelley captures a 3D scan of the ice cliff face with LiDAR (Light Detection And Ranging).

Other scientists studied the insulated glaciers from a different perspective: edge-on. They used laser ranging techniques to find out how the face of an ash-coated ice cliff morphed and receded throughout our week of work. We’ll compare these on-the-ground measurements with orbital images of the same area captured over longer periods of time. Combining field data and satellite imagery helps us better understand how the glaciers are evolving.

Planetary Science, Close to Home

We’re a team of planetary scientists, so our science questions on this trip applied to both Earth and other worlds. How does a blanket of ash affect the way glaciers are preserved? What chemical and mineral signatures can we find in the debris from a huge volcano like this one, and how are those signatures changing? What can the patterns we see today tell us about how microbial life has interacted with rock in this extreme environment?

Alexandra Matiella Novak, Patrick Whelley, and Cherie Achilles collect samples of volcanic debris from areas with different chemical and mineral compositions.

Studying fumaroles (openings in the ground where volcanic gases escape) for signs of mineral alteration and movement. Left to right: Heather Graham takes notes; Aditi Pandey and Justin Hayles decide where to collect samples; Tabb Prissel holds up a bag of steaming debris scooped from inside of a fumarole.

Many planets and moons have volcanic pasts, and we’re still trying to learn exactly what kinds of volcanism have shaped their surfaces. Ice is common throughout our solar system, too. Ground-truth data from field sites like this one can help us interpret evidence found on faraway worlds, where it’s harder to collect and examine samples.

Learn More

Into the Field with NASA: Valley of Ten Thousand Smokes

Comparing Earth and Other Worlds: NASA Planetary Analogs

Katmai National Park: The 1912 Novarupta-Katmai Eruption

Second Stop: The 2019 Arctic Tundra Fire in Greenland

July 29th, 2024 by Sonja Granqvist/University of Helsinki

A combined team from the University of Helsinki (Environmental Change Research Unit), the Finnish Meteorological Institute (Atmospheric Composition Unit), and the Vrije Universiteit Amsterdam (Climate & Ecosystems Change) was on its way again to gather groundbreaking data on carbon and aerosol emissions from increasing fires in the northern high latitudes. Our journey began in boreal Quebec and now continues to Arctic Greenland.

Meet the team: Elmiina Pilkama, Meri Ruppel, Sonja Granqvist, Sander Veraverbeke, and Lucas Diaz (from left to right).

Climate change is warming the Arctic with partly unexpected consequences. In recent years, unprecedented wildfires have raged through Arctic permafrost terrain burning in 2019 and 2020 alone, an area equal to half of what burned in the previous 40 years. In Greenland, a land known for its icy expanse, fires are rare. However, in July and August 2019, the second-largest wildfire recorded on the island occurred at the Kangerluarsuk Tulleq, northeast of Sisimiut. To our knowledge, fire effects in Greenland have never been studied—until now, as we begin our investigation.

The Kangerluarsuk Tulleq fire: A differenced Normalized Burn Ratio (dNBR), a proxy of fire severity, map created by using Sentinel 2-data by Lucas Diaz; landscape image of the fire scar taken from a southwest-facing perspective, looking downhill. Five years after the fire, the previously burned area is now dominated by red mosses (photo by Lucas Diaz).

To estimate the carbon burned and greenhouse gases and aerosols released during tundra fires, we assess post-fire ecosystem effects. We measure the dominant ecosystem types within the fire scar and compare them with unburned areas. We evaluate fire severity, and we conduct various aboveground and belowground measurements to calculate and date carbon stores.

Our campaign aimed to efficiently use 29 hours at the destination by collecting samples from all major ecosystems within the fire scar. We arrived by boat (hiking from Sisimiut is also possible but would take 2 days) and spent the day sampling. We camped near the shore, with some of us taking a daring dip in the sea. We continued sampling the next day before returning to Sisimiut in the evening. The study area exemplified the Arctic steppe ecoregion, featuring fragmented ecosystems ranging from barren rocky slopes and drier fields dominated by moss and lichen to moderately wet peatlands. We successfully collected a diverse set of samples from various ecosystems for detailed lab experiments and analysis to be performed back in Finland.           

Field measurements: Sonja Granqvist and Lucas Diaz measuring Betula nana shrubs. In the background, Sander Veraverbeke conducting a fire severity analysis; Elmiina Pilkama wrapping a soil core and Sonja Granqvist preparing the permafrost probe (photos by Lucas Diaz).

As we were preparing to head home from Greenland, we encountered unexpected foggy weather, which led to flight cancellations for several days. This gave us a well-appreciated few extra days of adventure. Three of us packed our hiking gear and embarked on an overnight hike. The summit of the two mountains we climbed was unforgettable. A key lesson for traveling in Greenland: keep your schedule flexible—it’s worth it!

Overall, the field campaign was a unique, once-in-a-lifetime experience. But that’s not all—can you guess where the fiery journey of Granqvist and Diaz will take them next? Stay tuned!

Mountain hiking memories: The summit of Nasaasaq Peak; a camp with a view (photos by Lucas Diaz and Elmiina Pilkama).

The Greenland fire expedition was organized within the Research Council of Finland Academy Research Fellow project “Fire in the Arctic,” led by Meri Ruppel, and the Kone Foundation project FLARE. The fieldwork was also part of FireIce (Fire in the land of ice: climatic drivers & feedbacks), a Consolidator project funded by the European Research Council. FireIce is affiliated with NASA’s Arctic-Boreal Vulnerability Experiment (ABoVE). This blog post was written by Sonja Granqvist, a Ph.D. student at the University of Helsinki, studying Arctic-boreal fires in collaboration with the Climate & Ecosystems Change research group from the Vrije Universiteit Amsterdam.

First Stop: Sampling the 2023 Fires in Quebec

June 25th, 2024 by Lucas Ribeiro Diaz, Vrije Universiteit Amsterdam

This blog post is the first in a series to come. Our team, the Climate & Ecosystems Change research group from the Vrije Universiteit Amsterdam, is working in collaboration with the Environmental Change Research Unit from the University of Helsinki for a summer with lots of fire field work, science, and adventure. On this journey, our first stop was the Quebec province in Canada. I’m writing this post after our last day of fieldwork here.

The 2023 wildfire season was the largest on record in Canada, with more than double the burned area as the second largest year. In Quebec, an estimated 4.5 million hectares were burned, an area slightly larger than the size of the Netherlands. This record-breaking fire season in Quebec was due to extreme warm and dry conditions. The dense smoke plumes from the 2023 Quebec blazes shocked the world when the smoke reached several cities on the US East Coast, including New York City.

Fellow scientists have been digging deep to understand and explain the phenomena involved in this Quebec fire season. However, as far as we know, estimates of carbon combustion, or the amount of carbon per area burned that is released during a fire, have never been made in Quebec. That’s why we are on it! In loco, since field measurements are a prime way to quantify carbon emissions from fires.

Meet the team: Thomas Janssen, Yuquan Qu, Lucas Diaz, Max van Gerrevink, Sonja Granqvist, and Sander Veraverbeke (from left to right).

We assess post-fire ecosystem effects to calculate carbon pools below and above ground. In other words, this is the carbon stored in the soil and vegetation. After collecting soil samples and inventorying the vegetation, we can compare burned and unburned (control) locations to estimate how much of this carbon was emitted to the atmosphere due to fire. We do this comparison based on what is called the adventitious root method. On black spruce trees, adventitious roots grow above the initial root collar into the upper soil layers and provide a reference for the pre-fire soil height, as they remain clearly visible many years after fire.

Work in progress: Lucas Diaz scouting for a plot location; Sonja Granqvist coring a tree for stand age estimation; Max van Gerrevink measuring adventitious root height; Yuquan Qu collecting a soil sample; Sander Veraverbeke giving an interview for a documentary; Thomas Janssen carrying out the tree inventory (from top/left to bottom/right).

During our expedition, we covered more than 4,000 kilometers on the road. We started by traveling north from Montreal along the James Bay Road and began our sampling at two fires near the locality of Radisson, where the remote Trans-Taiga road was our daily route. We then headed to Waskaganish, on the southeast shore of James Bay, where we sampled another fire. Finally, we ended our campaign at a large fire in the commercial forest near the town of Lebel-sur-Quévillon. All these trips allowed us to make a scientifically interesting transect from North to South in the Quebec province. We also got to know some incredible places, and we are grateful to the people living there who welcomed us.

We were able to observe two different types of intermixed ecosystems in the fires we visited. We found forests dominated by black spruce in peaty lowlands. In drier and often rocky uplands, Jack pine trees dominated. I’m curious to see how these differences will be reflected in practice when we analyze the carbon combustion in these systems.

Two different ecosystems: Black spruce-dominated forests in peaty lowlands (left) and Jack pine dominated forests in dry uplands (right).

Our team in the campaign was Lucas Diaz, Max van Gerrevink, Thomas Janssen, Yuquan Qu, and Sander Veraverbeke from VU Amsterdam, and Sonja Granqvist from the University of Helsinki. The success of this expedition is also thanks to our collaborators here in Quebec who helped us during our preparation: Dominique Arseneault (Université du Québec à Rimouski), Jonathan Boucher and Yan Boulanger (Canadian Forest Service), and Fabio Gennaretti (Université du Québec en Abitibi-Témiscamingue).

This fieldwork is part of my PhD project, so I was responsible for leading and organizing the entire expedition. As hard as it was, the whole process was also a lot of fun. Several times during the campaign, I felt like I was on a holiday road trip with a group of friends. In the end, that’s not entirely wrong. This kind of experience brings us closer to people. It strengthens existing bonds and creates new ones. This great adventure gave me moments that I will remember forever.

Time passes quickly here in the boreal forest. Soon, it will be time to pack our bags and embark on the next stage of this fiery journey. Curious about the destination? Stay tuned!

Building memories (from left to right): our campsite near the Trans-Taiga Road; sunset in the boreal forest; the joy of a mission accomplished.

The Quebec fires expedition is part of FireIce (Fire in the land of ice: climatic drivers & feedbacks). FireIce is a Consolidator project funded by the European Research Council. FireIce is affiliated with NASA’s Arctic-Boreal Vulnerability Experiment (ABoVE). This blog post was written by Lucas Ribeiro Diaz, a Ph.D. student at Vrije Universiteit Amsterdam, studying Arctic-boreal fires by combining field and remote sensing approaches.

Springtime in the Deciduous Forest

May 6th, 2024 by Fred Huemmrich, Petya Campbell, Greg Cain, Zoe Gentes

The view from the top of the tower shows leaves emerging across the deciduous forest.

On a blustery March morning, Petya Campbell stood atop a 204-foot-tall tower and looked across the waving canopy of the leafless deciduous forest at the Smithsonian Environmental Research Center in Edgewater, Maryland. This forest is predominately tulip poplar (Liriodendron tulipifera), and the tower extends over trees that are over 120 feet tall.

Petya, from the University of Maryland Baltimore County and NASA Goddard Space Flight Center, is working with Greg Cain, a master technician from the Battelle-managed National Ecology Observatory Network (NEON)—the U.S. National Science Foundation-funded program that runs the tower at the Smithsonian site (SERC). Petya and Greg were on the tower that day to install a new type of instrument, an automated spectrometer called a NoX (Near Infrared Box). The NoX measures the light reflectance off the forest canopy in hundreds of narrow spectral bands through the visible wavelengths we can see and into the near-infrared bands beyond our vision. The instrument will make these measurements every few minutes throughout the entire growing season.

This photo shows the SERC flux tower, looking up from its base. The thin line coming off of the right side of the tower’s top is the pole that supports the fiber-optic cable for the NoX.

Petya and Greg stand on top of the tower.

In addition, NEON runs instruments on this tower that take measurements of the movement of carbon dioxide (CO2) into and out of the forest. CO2 is absorbed from the atmosphere into the trees through photosynthesis, so measuring the amount of CO2 taken up by the plants is a measure of forest productivity. These CO2 flux measurements are collected continuously and reported every half hour.

The time series of spectral reflectance measured by the NoX can provide information about leaf characteristics. For instance, it can tell scientists about the amount of green biomass and chlorophyll in the leaves, which determines the potential productivity of the forest; the amount of other leaf pigments that are used to protect the leaves from damage, which indicate when the trees are under stress; and the amount of water in the leaves, which can be used to detect drought stress.

Researchers will use data from the NoX to gain insight into the functioning of this deciduous forest as it responds to environmental conditions such as hot or cold spells, droughts or rainy periods, and sunny or cloudy days. They will observe seasonal changes from the time the leaves emerge in the spring, through the green of the summer, the changing colors of the autumn, and finally the loss of the leaves at the end of the growing season. Others can watch the forest change through the seasons using the phenocam, a web camera mounted on the tower that regularly takes photographs to monitor the changes in the forest.

The upward viewing fiber-optic from the NoX views the sunlight shining down on the forest (left). The downward looking fiber-optic from the NoX is extended out on a pole from the tower to view the forest below (right).

Installing the NoX on the SERC tower is just the most recent deployment by Petya Campbell and Fred Huemmrich. Over the past couple of yeavrs, they have installed similar instruments on flux towers in the arctic tundra and boreal forest.

The NoX data will be compared with the tower flux data to develop and test relationships between spectral reflectance and forest productivity and the detection of stress responses under adverse conditions. Understanding these types of relationships and how they may differ between vegetation types and season will aid the development of future NASA missions such as the Surface Biology and Geology (SBG) study, and the Geosynchronous Littoral Imaging and Monitoring Radiometer (GLIMR), which will collect spectral information similar to the NoX over large areas of the Earth.

The flux tower sits in the middle of the Smithsonian Forest Global Earth Observatory (ForestGEO) site. ForestGEO is a global network of forest sites where every tree whose trunk is larger than 1 centimeter in diameter is measured and tagged to track biodiversity and the growth and mortality of trees.

The early blooming spring beauties (Claytonia virginica) show that the growing season for the forest is starting and that it is a good time to get the NoX up and running.