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The Marshall Star for July 24, 2024


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The Marshall Star for July 24, 2024

An artist’s illustration depicting NASA’s Chandra X-ray Observatory in flight, with a vivid star field behind it. Chandra’s solar panels are deployed and its camera “eye” open on the cosmos.

25 Years On, Chandra Highlights Legacy of NASA Engineering Ingenuity

By Rick Smith

“The art of aerospace engineering is a matter of seeing around corners,” said NASA thermal analyst Jodi Turk. In the case of NASA’s Chandra X-ray Observatory, marking its 25th anniversary in space this year, some of those corners proved to be as far as 80,000 miles away and a quarter-century in the future.

Turk is part of a dedicated team of engineers, designers, test technicians, and analysts at NASA’s Marshall Space Flight Center. Together with partners outside and across the agency, including the Chandra Operations Control Center in Burlington, Massachusetts, they keep the spacecraft flying, enabling Chandra’s ongoing studies of black holes, supernovae, dark matter, and more – and deepening our understanding of the origin and evolution of the cosmos.

Engineers in the X-ray Calibration Facility – now the world-class X-ray & Cryogenic Facility – at NASA’s Marshall Space Flight Center in Huntsville, Alabama, integrate the Chandra X-ray Observatory’s High Resolution Camera with the mirror assembly inside a 24-foot-diameter vacuum chamber, in this photo taken March 16, 1997. Chandra was launched July 23, 1999, aboard space shuttle Columbia. (NASA) Engineers in head-to-toe cleanroom suits conduct final integration of the Chandra X-ray Observatory’s sensitive camera equipment and high-powered mirror assembly, working inside a mammoth, tube-like vacuum chamber at NASA’s Marshall Space Flight Center.
Engineers in the X-ray Calibration Facility – now the world-class X-ray & Cryogenic Facility – at NASA’s Marshall Space Flight Center integrate the Chandra X-ray Observatory’s High Resolution Camera with the mirror assembly inside a 24-foot-diameter vacuum chamber, in this photo taken March 16, 1997. Chandra was launched July 23, 1999, aboard space shuttle Columbia.
NASA

“Everything Chandra has shown us over the last 25 years – the formation of galaxies and super star clusters, the behavior and evolution of supermassive black holes, proof of dark matter and gravitational wave events, the viability of habitable exoplanets – has been fascinating,” said retired NASA astrophysicist Martin Weisskopf, who led Chandra scientific development at Marshall beginning in the late 1970s. “Chandra has opened new windows in astrophysics that we’d hardly begun to imagine in the years prior to launch.”

Following extensive development and testing by a contract team managed and led by Marshall, Chandra was lifted to space aboard the space shuttle Columbia on July 23, 1999. Marshall has continued to manage the program for NASA ever since.

“How much technology from 1999 is still in use today?” said Chandra researcher Douglas Swartz. “We don’t use the same camera equipment, computers, or phones from that era. But one technological success – Chandra – is still going strong, and still so powerful that it can read a stop sign from 12 miles away.”

That lasting value is no accident. During early concept development, Chandra – known prior to launch as the Advanced X-ray Astrophysics Facility – was intended to be a 15-year, serviceable mission like that of NASA’s Hubble Space Telescope, enabling periodic upgrades by visiting astronauts.

sts093-705-020~large.jpg?w=1920&h=1920&f
The Chandra X-Ray Observatory, the longest cargo ever carried to space aboard the space shuttle, seen in Columbia’s payload bay prior to being tilted upward for release and deployment on July 23, 1999.
NASA

But in the early 1990s, as NASA laid plans to build the International Space Station in orbit, the new X-ray observatory’s budget was revised. A new, elliptical orbit would carry Chandra a third of the way to the Moon, or roughly 80,000 miles from Earth at apogee. That meant a shorter mission life – five years – and no periodic servicing.

The engineering design team at Marshall, its contractors, and the mission support team at the Smithsonian Astrophysical Observatory revised their plan, minimizing the impact to Chandra’s science. In doing so, they enabled a long-running science mission so successful that it would capture the imagination of the nation and lead NASA to extend its duration past that initial five-year period.

“There was a lot of excitement and a lot of challenges – but we met them and conquered them,” said Marshall project engineer David Hood, who joined the Chandra development effort in 1988.

“The field of high-powered X-ray astronomy was still so relatively young, it wasn’t just a matter of building a revolutionary observatory,” Weisskopf said. “First, we had to build the tools necessary to test, analyze, and refine the hardware.”

sts093-706-035~large.jpg?w=1911&h=1919&f
On July 23, 1999, the Chandra X-Ray Observatory is released from space shuttle Columbia’s payload bay. Twenty-five years later, Chandra continues to make valuable discoveries about high-energy sources and phenomena across the universe.
NASA

Marshall renovated and expanded its X-ray Calibration Facility – now known as the X-ray & Cryogenic Facility – to calibrate Chandra’s instruments and conduct space-like environment testing of sensitive hardware. That work would, years later, pave the way for Marshall testing of advanced mirror optics for NASA’s James Webb Space Telescope.

“Marshall has a proven history of designing for long-term excellence and extending our lifespan margins,” Turk said. “Our missions often tend to last well past their end date.”

Chandra is a case in point. The team has automated some of Chandra’s operations for efficiency. They also closely monitor key elements of the spacecraft, such as its thermal protection system, which have degraded as anticipated over time, due to the punishing effects of the space environment.

“Chandra’s still a workhorse, but one that needs gentler handling,” Turk said. The team met that challenge by meticulously modeling and tracking Chandra’s position and behavior in orbit and paying close attention to radiation, changes in momentum, and other obstacles. They have also employed creative approaches, making use of data from sensors on the spacecraft in new ways.

An artist’s illustration depicting NASA’s Chandra X-ray Observatory in flight, with a vivid star field behind it. Chandra’s solar panels are deployed and its camera “eye” open on the cosmos.
An artist’s illustration depicting NASA’s Chandra X-ray Observatory in flight, with a vivid star field behind it. Chandra’s solar panels are deployed and its camera “eye” open on the cosmos.
NASA

Acting project manager Andrew Schnell, who leads the Chandra team at Marshall, said the mission’s length means the spacecraft is now overseen by numerous “third-generation engineers” such as Turk. He said they’re just as dedicated and driven as their senior counterparts, who helped deliver Chandra to launch 25 years ago.

The work also provides a one-of-a-kind teaching opportunity, Turk said. “Troubleshooting Chandra has taught us how to find alternate solutions for everything from an interrupted sensor reading to aging thermocouples, helping us more accurately diagnose issues with other flight hardware and informing design and planning for future missions,” she said.

Well-informed, practically trained engineers and scientists are foundational to productive teams, Hood said – a fact so crucial to Chandra’s success that its project leads and support engineers documented the experience in a paper titled, “Lessons We Learned Designing and Building the Chandra Telescope.”

“Former program manager Fred Wojtalik said it best: ‘Teams win,’” Hood said. “The most important person on any team is the person doing their work to the best of their ability, with enthusiasm and pride. That’s why I’m confident Chandra’s still got some good years ahead of her. Because that foundation has never changed.”

As Chandra turns the corner on its silver anniversary, the team on the ground is ready for whatever fresh challenge comes next.

Learn more about the Chandra X-ray Observatory and its mission.

Smith, an Aeyon/MTS employee, supports the Marshall Office of Communications.

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NASA Sounding Rocket Launches, Studies Heating of Sun’s Active Regions

By Wayne Smith

Investigators at NASA’s Marshall Space Flight Center will use observations from a recently launched sounding rocket mission to provide a clearer image of how and why the Sun’s corona grows so much hotter than the visible surface of Earth’s parent star. The MaGIXS-2 mission – short for the second flight of the Marshall Grazing Incidence X-ray Spectrometer – launched from White Sands Missile Range in New Mexico on July 16.

The mission’s goal is to determine the heating mechanisms in active regions on the Sun by making critical observations using X-ray spectroscopy.

A sounding rocket launches into a bright blue sky leaving a plume of smoke behind.
NASA’s MaGIXS-2 sounding rocket mission successfully launches from White Sands Missile Range in New Mexico on July 16.
United States Navy

The Sun’s surface temperature is around 10,000 degrees Fahrenheit – but the corona routinely measures more than 1.8 million degrees, with active regions measuring up to 5 million degrees.

Amy Winebarger, Marshall heliophysicist and principal investigator for the MaGIXS missions, said studying the X-rays from the Sun sheds light on what’s happening in the solar atmosphere – which, in turn, directly impacts Earth and the entire solar system.

X-ray spectroscopy provides unique capabilities for answering fundamental questions in solar physics and for potentially predicting the onset of energetic eruptions on the Sun like solar flares or coronal mass ejections. These violent outbursts can interfere with communications satellites and electronic systems, even causing physical drag on satellites as Earth’s atmosphere expands to absorb the added solar energy.

“Learning more about these solar events and being able to predict them are the kind of things we need to do to better live in this solar system with our Sun,” Winebarger said.

The NASA team retrieved the payload immediately after the flight and has begun processing datasets.

“We have these active regions on the Sun, and these areas are very hot, much hotter than even the rest of the corona,” said Patrick Champey, deputy principal investigator at Marshall for the mission. “There’s been a big question – how are these regions heated? We previously determined it could relate to how often energy is released. The X-rays are particularly sensitive to this frequency number, and so we built an instrument to look at the X-ray spectra and disentangle the data.”

A group of around 30 individuals stand in front of a sounding rocket on a launch pad at a facility in White Sands, New Mexico.
The MaGIXS-2 sounding rocket team stand on the launchpad in White Sands, New Mexico, prior to launch July 16.
United States Navy

Following a successful July 2021 launch of the first MaGIXS mission, Marshall and its partners refined instrumentation for MaGIXS-2 to provide a broader view for observing the Sun’s X-rays. Marshall engineers developed and fabricated the telescope and spectrometer mirrors, and the camera. The integrated instrument was exhaustively tested in Marshall’s state-of-the-art X-ray & Cryogenic Facility. For MaGIXS-2, the team refined the same mirrors used on the first flight, with a much larger aperture and completed the testing at Marshall’s Stray Light Test Facility.

A Marshall project from inception, technology developments for MaGIXS include the low-noise CCD camera, high-resolution X-ray optics, calibration methods, and more.

Winebarger and Champey said MaGIXS many of the team members started their NASA careers with the project, learning to take on lead roles and benefitting from mentorship.

“I think that’s probably the most critical thing, aside from the technology, for being successful,” Winebarger said. “It’s very rare that you get from concept to flight in a few years. A young engineer can go all the way to flight, come to White Sands to watch it launch, and retrieve it.”

NASA routinely uses sounding rockets for brief, focused science missions. They’re often smaller, more affordable, and faster to design and build than large-scale satellite missions, Winebarger said. Sounding rockets carry scientific instruments into space along a parabolic trajectory. Their overall time in space is brief, typically five minutes, and at lower vehicle speeds for a well-placed scientific experiment.

The MaGIXS mission was developed at Marshall in partnership with the Smithsonian Astrophysical Observatory in Cambridge, Massachusetts. The Sounding Rockets Program Office, located at NASA Goddard Space Flight Center’s Wallops Flight Facility, provides suborbital launch vehicles, payload development, and field operations support to NASA and other government agencies. 

Smith, a Media Fusion employee and the Marshall Star editor, supports the Marshall Office of Communications.

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From 1 Crew to Another: Artemis II Astronauts Meet NASA Barge Crew

Members of the Artemis II crew met with the crew of NASA’s Pegasus barge prior to their departure to deliver the core stage of NASA’s SLS (Space Launch System) rocket to the Space Coast.

NASA astronaut and pilot of the Artemis II mission Victor Glover met the crew July 15. NASA astronaut Reid Wiseman, commander, and CSA (Canadian Space Agency) astronaut Jeremy Hansen, mission specialist, visited the barge July 16 shortly before the flight hardware was loaded onto it.

From left to right: Ashley Marlar, Jamie Crews, Nick Owen, Jeffery Whitehead, Scott Ledet, Jason Dickerson, John Campbell, NASA astronaut Victor Glover, Farid Sayah, Kelton Hutchinson, Terry Fitzgerald, Bryan Jones, and Joe Robinson.
Crew members of NASA’s Pegasus barge meet with NASA astronaut Victor Glover at NASA’s Michoud Assembly Facility prior to their departure to deliver the core stage of NASA’s SLS (Space Launch System) rocket to the Space Coast. From left are Ashley Marlar, Jamie Crews, Nick Owen, Jefferey Whitehead, Scott Ledet, Jason Dickerson, John Campbell, Glover, Farid Sayah, Kelton Hutchinson, Terry Fitzgerald, Bryan Jones, and Joe Robinson.
NASA/Brandon Hancock

Pegasus is currently transporting the SLS core stage from NASA’s Michoud Assembly Facility to NASA’s Kennedy Space Center, where it will be integrated and prepared for launch. During the Artemis II test flight, the core stage with its four RS-25 engines will provide more than 2 million pounds of thrust to help send the Artemis II crew around the Moon.

The Pegasus crew and team, from left, includes Kelton Hutchinson, Jeffery Whitehead, Jason Dickerson, Arlan Cochran, John Brunson, NASA astronaut Reid Wiseman of the Artemis II crew, Marc Verhage, Terry Fitzgerald, Scott Ledet, CSA astronaut Jeremy Hansen of the Artemis II crew, Wil Daly, Ashley Marlar, Farid Sayah, Jamie Crews, Joe Robinson, and Nick Owen.
The Pegasus crew and team, from left, includes Kelton Hutchinson, Jeffery Whitehead, Jason Dickerson, Arlan Cochran, John Brunson, NASA astronaut Reid Wiseman, Marc Verhage, Terry Fitzgerald, Scott Ledet, CSA astronaut Jeremy Hansen, Wil Daly, Ashley Marlar, Farid Sayah, Jamie Crews, Joe Robinson, and Nick Owen.
NASA/Sam Lott

Pegasus, which was previously used to ferry space shuttle tanks, was modified and refurbished to ferry the SLS rocket’s massive core stage. At 212 feet in length and 27.6 feet in diameter, the Moon rocket stage is more than 50 feet longer than the space shuttle external tank.

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I am Artemis: John Campbell

How do you move NASA’s SLS (Space Launch System) rocket’s massive 212-foot-long core stage across the country? You do it with a 300-foot-long barge. However, NASA’s Pegasus barge isn’t just any barge. It’s a vessel with a history, and John Campbell, a logistics engineer for the agency based at NASA’s Marshall Space Flight Center, is one of the few people who get to be a part of its legacy.

John Campbell, a logistics engineer at NASA’s Marshall Space Flight Center, stands on NASA's Pegasus barge July 15 for the Artemis II core stage rollout.
John Campbell, a logistics engineer at NASA’s Marshall Space Flight Center, stands on NASA’s Pegasus barge July 15.
NASA

For Campbell, this journey is more than just a job – it’s a lifelong passion realized. “Ever since I was a boy, I’ve been fascinated by engineering,” he said. “But to be entrusted with managing NASA’s Pegasus barge, transporting history-making hardware for human spaceflight across state lines and waterways – is something I never imagined.”

NASA has used barges to ferry the large and heavy hardware elements of its rockets since the Apollo Program. Replacing the agency’s Poseidon and Orion barges, Pegasus was originally crafted for the Space Shuttle Program and updated in recent years to help usher in the Artemis Generation and accommodate the mammoth dimensions of the SLS core stage. The barge plays a big role in NASA’s logistical operations, navigating rivers and coastal waters across the Southeast, and has transported key structural test hardware for SLS in recent years.

Campbell grew up in Muscle Shoals, Alabama. After graduating from the University of Alabama with a degree in mechanical engineering, he ventured south to Panama City, Florida, where he spent a few years with a heating, ventilation, and air conditioning consulting team. Looking for an opportunity to move home, he applied for and landed a contractor position with NASA and soon moved to his current civil service role.

With 17 years under his belt, Campbell has many fond memories during his time with the agency. One standout moment was witnessing the space shuttle stacked in the Vehicle Assembly Building at NASA’s Kennedy Space Center. But it’s not all about rockets and launch pads for Campbell. When he isn’t in his office making sure Pegasus has everything it needs for its next trip out, he is on the water accompanying important pieces of hardware to their next destinations. With eight trips on Pegasus under his belt, the journey never gets old.

“There is something peaceful when you look out and it’s just you, the water, one or two other boats, and wildlife,” Campbell said. “On one trip we had a pod of at least 20 dolphins surrounding us. You get to see all kinds of cool wildlife and scenery.”

From cherishing special moments like this to ensuring the success of each journey, Campbell recognizes the vital role he plays in the agency’s goals to travel back to the Moon and beyond and does not take his responsibility lightly.

“To be a part of the Artemis campaign and the future of space is just cool. I was there when the barge underwent its transformation to accommodate the colossal core stage, and in that moment, I realized I was witnessing history unfold. Though I couldn’t be present at the launch of Artemis I, watching it on TV was an emotional experience. To see something you’ve been a part of, something you’ve watched evolve from mere components to a giant spacecraft hurtling into space – it’s a feeling beyond words.”

NASA is working to land the first woman, first person of color, and its first international partner astronaut on the Moon under Artemis. SLS is part of NASA’s backbone for deep space exploration, along with the Orion spacecraft, supporting ground systems, advanced spacesuits and rovers, the Gateway in orbit around the Moon, and commercial human landing systems. SLS is the only rocket that can send Orion, astronauts, and supplies to the Moon in a single launch.

Marshall manages the SLS Program.

Read other I am Artemis features.

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Icelandic Graduate Student Brings High-Performance Computing Knowledge to IMPACT

By Derek Koehl

For the last six months, NASA’s Interagency Implementation and Advanced Concepts Team (IMPACT) foundation model development team at NASA’s Marshall Space Flight Center, has been joined by Þorsteinn Elí Gíslason, a visiting graduate student at the University of Alabama in Huntsville from the University of Iceland.

His participation on the Prithvi geospatial foundation model, an open-source geospatial artificial intelligence (AI) foundation model for Earth observation data, was part of a collaboration partnership between NASA, the University of Alabama in Huntsville (UAH), the University of Iceland, and the Jülich Supercomputing Centre in Forschungszentrum Jülich, Germany. 

Þorsteinn Elí Gíslason, a graduate student from the University of Iceland, is supported by NASA’s Interagency Implementation and Advanced Concepts Team (IMPACT) at NASA’s Marshall Space Flight Center.
Þorsteinn Elí Gíslason, a graduate student from the University of Iceland, is supported by NASA’s Interagency Implementation and Advanced Concepts Team (IMPACT) at NASA’s Marshall Space Flight Center.
NASA

The goal of the collaboration was to share expertise and knowledge across institutions in an open and synergetic way. This partnership serves as a pathfinder for students to work on an international collaborative project and provides extensive research opportunities to graduate students like Elí in fields such as AI foundation models and high-performance computing (HPC). 

“Elí demonstrated exceptional support in running experiments on the geospatial foundation model, showcasing his expertise and dedication,” said Sujit Roy, Gíslason’s mentor and IMPACT FM team lead from UAH. “I loved one specific quality of Elí, that he asks a lot of questions and puts effort into understanding the problem statement.”

Gíslason was instrumental in helping the team overcome the hoops and hurdles involved when pre-training a foundation model on a high-performance computing system. His ability to understand models and scale them to multiple graphics processing units (GPUs) was an instrumental skill for the project. He facilitated scripts and simulations to run seamlessly over multiple nodes and GPUs, optimizing resources and accelerating research outcomes. Additionally, Elí’s adeptness in running these models on high-performance computing systems significantly enhanced the team’s computational efficiency. Gíslason also contributed his knowledge of the Jülich Supercomputing Centre’s HPC systems and served an important role with respect to the Centre’s operations. 

By helping the team overcome the challenges of pre-training, Gíslason’s interest in AI models expanded.

“For as long as I can remember, I’ve been interested in programming and computers. I’ve always found it fun to apply programming to a problem I’m facing, especially if it has the opportunity to reduce the overall work required,” said Gíslason. “AI, machine learning, and deep learning are just advanced forms of this interest. These models capture my interest in that they are able to solve problems by capturing patterns that don’t have to be explicitly defined beforehand.”

Gíslason’s work with IMPACT supports his master’s thesis in computational engineering at the University of Iceland. His graduate work builds on his Bachelor of Science in physics. 

This collaboration was facilitated by Gabriele Cavallaro from Jülich Supercomputing Center and Manil Maskey, IMPACT deputy project manager and research scientist at Marshall. 

“Open science thrives on sharing expertise, and artificial intelligence encompasses a vast field requiring knowledge across many areas,” Maskey said. “Elí provided one of the key expertise areas crucial to our project. This collaboration was mutually beneficial- our foundation model project gained from his specialized knowledge, while Elí gained valuable technical skills and experience as part of a major NASA project.”

IMPACT is managed by Marshall and is part of the center’s Earth Science branch. The collaboration was conducted through the IEEE Geoscience and Remote Sensing Society Earth Science Informatics Technical Committee. Along with IMPACT and Marshall, development of the Prithvi geospatial foundation model featured significant contributions from NASA’s Office of the Chief Science Data Officer, IBM Research, Oak Ridge National Laboratory, and the University of Alabama in Huntsville.

Koehl is a research associate at the University of Alabama in Huntsville supporting IMPACT.

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Delta Aquariid Meteor Shower Best Seen in Southern Hemisphere in Late July

Most casual skywatchers know the bright, busy Perseids meteor shower arrives in late July and peaks in mid-August. Fewer are likely to name-drop the Southern delta Aquariids, which overlap with the Perseids each summer and are typically outshone by their brighter counterparts, especially when the Moon washes out the Southern delta Aquariids.

Perseids meteors – which coincide with the Southern Delta Aquariids at the tail end of July – streak over Sequoia National Forest in this 2023 NASA file photo.
Perseids meteors – which coincide with the Southern Delta Aquariids at the tail end of July – streak over Sequoia National Forest in this 2023 NASA file photo.
NASA/Preston Dyches)

This year, with the Southern delta Aquariids set to peak on the night of July 28, the underdog shower isn’t likely to deliver any surprises. Unless you’re below the equator, it’ll take a keen eye to spot one.

“The Southern delta Aquariids have a very strong presence on meteor radars which can last for weeks,” said NASA astronomer Bill Cooke, who leads the Meteoroid Environment Office at NASA’s Marshall Space Flight Center. “Sadly, for most observers in the Northern Hemisphere, they’re difficult to spot with the naked eye, requiring the darkest possible skies.”

Meteor watchers – particularly those in the southern United States and points south – will be best served to check out the night sky July 28-29 before moonrise at 2 a.m.

During peak shower activity, under ideal viewing conditions with no Moon in the sky, casual watchers may see 2-5 meteors per hour, flashing into view at speeds of 25 miles per second. A small percentage of these may leave glowing, ionized gas trails that linger visibly for a second or two after the meteor has passed. But most of the noticeable activity for the Southern delta Aquariids occurs over a couple of days around its peak, so don’t expect to see any past the end of July.

You can distinguish Southern delta Aquariids meteors from the Perseids by identifying their radiant, or the point in the sky from which a meteor appears to originate. Southern delta Aquariids appear to come from the direction of the constellation of Aquarius, hence the name. The Perseids’ radiant is in the constellation of Perseus in the northern sky.

Most astronomers agree the Southern delta Aquariids originate from Comet 96P/Machholz, which orbits the Sun every 5.3 years. Discovered by Donald Machholz in 1986, the comet’s nucleus is roughly 4 miles across – about half the size of the object suspected to have wiped out the dinosaurs. Researchers think debris causing the Southern delta Aquariid meteor shower was generated about 20,000 years ago.

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Juno Mission Captures Colorful, Chaotic Clouds of Jupiter

During its 61st close flyby of Jupiter on May 12, NASA’s Juno spacecraft captured a color-enhanced view of the giant planet’s northern hemisphere. It provides a detailed view of chaotic clouds and cyclonic storms in an area known to scientists as a folded filamentary region. In these regions, the zonal jets that create the familiar banded patterns in Jupiter’s clouds break down, leading to turbulent patterns and cloud structures that rapidly evolve over the course of only a few days.

Jupiter
During its 61st close flyby of Jupiter on May 12, NASA’s Juno spacecraft captured a color-enhanced view of the giant planet’s northern hemisphere.
Image data: NASA/JPL-Caltech/SwRI/MSSS. Image processing by Gary Eason © CC BY

Citizen scientist Gary Eason made this image using raw data from the JunoCam instrument, applying digital processing techniques to enhance color and clarity.

At the time the raw image was taken, the Juno spacecraft was about 18,000 miles above Jupiter’s cloud tops, at a latitude of about 68 degrees north of the equator.

JunoCam’s raw images are available for the public to peruse and process into image products at https://missionjuno.swri.edu/junocam/processing. More information about NASA citizen science can be found at https://science.nasa.gov/citizenscience.

NASA’s Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, manages the Juno mission for the principal investigator, Scott Bolton, of the Southwest Research Institute in San Antonio. Juno is part of NASA’s New Frontiers Program, which is managed at NASA’s Marshall Space Flight Center for the agency’s Science Mission Directorate. The Italian Space Agency (ASI) funded the Jovian InfraRed Auroral Mapper. Lockheed Martin Space in Denver built and operates the spacecraft.

Learn more about Juno.

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      California’s giant kelp forests serve as a major foundation for the region’s rich marine biodiversity and provide recreational and economic value to the State of California. With the rising frequency of marine heatwaves and extreme weather onset by climate change, it has become increasingly important to study these vital ecosystems. Kelp forests are highly dynamic, changing across several timescales; seasonally due to nutrient concentrations, waves, and predator populations, weekly with typical growth and decay, and hourly with the tides and currents. Previous remote sensing of kelp canopies has relied on Landsat imagery taken with a eight-day interval, limiting the ability to quantify more rapid changes. This project aims to address uncertainty in kelp canopy detection using the Harmonized Landsat and Sentinel-2 (HLS) dataset’s zero to five-day revisit period. A random forest classifier was used to identify pixels that contain kelp, on which Multiple Endmember Spectral Mixture Analysis (MESMA) was then run to quantify intrapixel kelp density. Processed multispectral satellite images taken within 3 days of one another were paired for comparison. The relationship between fluctuations in kelp canopy density with tides and currents was assessed using in situ data from an acoustic doppler current profiler (ADCP) at the Santa Barbara Long Term Ecological Research site (LTER) and a NOAA tidal buoy. Preliminary results show that current and tidal trends cannot be accurately correlated with canopy detection due to other sources of error. We found that under cloud-free conditions, canopy detection between paired images varied on average by 42%. Standardized image processing suggests that this uncertainty is not created within the image processing step, but likely arises due to exterior factors such as sensor signal noise, atmospheric conditions, and sea state. Ultimately, these errors could lead to misinterpretation of remotely sensed kelp ecosystems, highlighting the need for further research to identify and account for uncertainties in remote sensing of kelp canopies.

      Jasmine Sirvent
      Kelp Us!: A Methods Analysis for Predicting Kelp Pigment Concentrations from Hyperspectral Reflectance
      Jasmine Sirvent
      Ocean color remote sensing enables researchers to assess the quantity and physiology of life in the ocean, which is imperative to understanding ecosystem health and formulating accurate predictions. However, without proper methods to analyze hyperspectral data, correlations between spectral reflectance and physiological traits cannot be accurately derived. In this study, I explored different methods—single variable regression, partial least squares regressions (PLSR), and derivatives—in analyzing in situ Macrocystis pyrifera (giant kelp) off the coast of Santa Barbara, California in order to predict pigment concentrations from AVIRIS hyperspectral reflectance. With derivatives as a spectral diagnostic tool, there is evidence suggesting high versus low pigment concentrations could be diagnosed; however, the fluctuations were within 10 nm of resolution, thus AVIRIS would be unable to reliably detect them. Exploring a different method, I plotted in situ pigment measurements — chlorophyll a, fucoxanthin, and the ratio of fucoxanthin to chlorophyll a—against hyperspectral reflectance that was resampled to AVIRIS bands. PLSR proved to be a more successful model because of its hyperdimensional analysis capabilities in accounting for multiple wavelength bands, reaching R2 values of 0.67. Using this information, I constructed a model that predicts kelp pigments from simulated AVIRIS reflectance using a spatial time series of laboratory spectral measurements and photosynthetic pigment concentrations. These results have implications, not only for kelp, but many other photosynthetic organisms detectable by hyperspectral airborne or satellite sensors. With these findings, airborne optical data could possibly predict a plethora of other biogeochemical traits. Potentially, this research would permit scientists to acquire data analogous to in situ measurements about floating matters that cannot financially and pragmatically be accessed by anything other than a remote sensor.

      Isabelle Cobb
      Correlations Between SSHa and Chl-a Concentrations in the Northern South China Sea
      Isabelle Cobb
      Sea surface height anomalies (SSHa)–variations in sea surface height from climatological averages–occur on seasonal timescales due to coastal upwelling and El Niño-Southern Oscillation (ENSO) cycles. These anomalies are heightened when upwelling plumes bring cold, nutrient-rich water to the surface, and are particularly strong along continental shelves in the Northern South China Sea (NSCS). This linkage between SSHa and nutrient availability has interesting implications for changing chlorophyll-a (chl-a) concentrations, a prominent indicator of phytoplankton biomass that is essential to the health of marine ecosystems. Here, we evaluate the long-term (15 years) relationship between SSHa and chl-a, in both satellite remote sensing data and in situ measurements. Level 3 SSHa data from Jason 1/2/3 satellites and chl-a data from MODIS Aqua were acquired and binned to monthly resolution. We found a significant inverse correlation between SSHa and chl-a during upwelling months in both the remote sensing (Spearman’s R=-0.57) and in situ data, with higher resolution in situ data from ORAS4 (an assimilation of buoy observations from 2003-2017) showing stronger correlations (Spearman’s R=-0.75). In addition, the data reveal that the magnitude of SSH increases with time during instances of high correlation, possibly indicating a trend of increased SSH associated with reduced seasonal chl-a concentrations. Thus, this relationship may inform future work predicting nutrient availability and threats to marine ecosystems as climate change continues to affect coastal sea surface heights.

      Alyssa Tou
      Exploring Coastal Sea Surface Temperature Anomalies and their effect on Coastal Fog through analyzing Plant Phenology
      Alyssa Tou
      Marine heat waves (MHW) have been increasing in frequency, duration and intensity, giving them substantial potential to influence ecosystems. Do these MHWs sufficiently enhance coastal precipitation such that plant growth is impacted? Recently, the Northeast Pacific experienced a long, intense MHW in 2014/2015, and another short, less intense MHW in 2019/2020. Here we investigate how the intensity and duration of MHWs influence the intensity and seasonal cycle of three different land cover types (‘grass’, ‘trees’, and a combination of both ‘combined’’) to analyze plant phenology trends in Big Sur, California. We hypothesize that longer intense MHWs decrease the ocean’s evaporative capacity, decreasing fog, thus lowering plant productivity, as measured by Normalized Difference Vegetation Index (NDVI). Sea surface temperature (SST) and NDVI data were collected from the NOAA Coral Reef Watch, and NASA MODIS/Terra Vegetation Indices 16-Day L3 Global 250m products respectively. Preliminary results show no correlation (R2=0.02) between SSTa and combined NDVI values and no correlation (R2=0.01) between SST and NDVI. This suggests that years with anomalously high SST do not significantly impact plant phenology. During the intense and long 2014/2015 MHW, peak NDVI values for ‘grass’ and ‘combined’ pixels were 2.0 and 1.7 standard deviations above the climatological average, while the shorter 2019/2020 MHW saw higher peaks of 3.2 and 2.4 standard deviations. However, the ‘grass’, ‘tree’ and ‘combined’ NDVI anomalies were statistically insignificant during both MHWs, showing that although NDVI appeared to increase during the shorter and less intense MHW, these values may be attributed to other factors. The data qualitatively suggest that MHW’s don’t impact the peak NDVI date, but more data at higher temporal resolution are necessary. Further research will involve analyzing fog indices and exploring confounding variables impacting NDVI, such as plant physiology, anthropogenic disturbance, and wildfires. In addition, it’s important to understand to what extent changes in NDVI are attributed to the driving factors of MHWs or the MHWs themselves. Ultimately, mechanistically understanding the impacts MHW intensity and duration have on terrestrial ecosystems will better inform coastal community resilience.


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      Last Updated Nov 22, 2024 Related Terms
      General Explore More
      10 min read SARP East 2024 Atmospheric Science Group
      Article 21 mins ago 10 min read SARP East 2024 Hydroecology Group
      Article 21 mins ago 11 min read SARP East 2024 Terrestrial Fluxes Group
      Article 22 mins ago View the full article
    • By NASA
      10 min read
      Preparations for Next Moonwalk Simulations Underway (and Underwater)
      Return to 2024 SARP Closeout Faculty Advisors:
      Dr. Guanyu Huang, Stony Brook University
      Graduate Mentor:
      Ryan Schmedding, McGill University

      Ryan Schmedding, Graduate Mentor
      Ryan Schmedding, graduate mentor for the 2024 SARP Atmospheric Science group, provides an introduction for each of the group members and shares behind-the scenes moments from the internship.
      Danielle Jones
      Remote sensing of poor air quality in mountains: A case study in Kathmandu, Nepal
      Danielle Jones
      Urban activity produces particulate matter in the atmosphere known as aerosol particles. These aerosols can negatively affect human health and cause changes to the climate system. Measures for aerosols include surface level PM2.5 concentration and aerosol optical depth (AOD). Kathmandu, Nepal is an urban area that rests in a valley on the edge of the Himalayas and is home to over three million people. Despite the prevailing easterly winds, local aerosols are mostly concentrated in the valley from the residential burning of coal followed by industry. Exposure to PM2.5 has caused an estimated ≥8.6% of deaths annually in Nepal. We paired NASA satellite AOD and elevation data, model  meteorological data, and local AirNow PM2.5 and air quality index (AQI) data to determine causes of variation in pollutant measurement during 2023, with increased emphasis on the post-monsoon season (Oct. 1 – Dec. 31). We see the seasonality of meteorological data related to PM2.5 and AQI. During periods of low temperature, low wind speed, and high pressure, PM2.5 and AQI data slightly diverge. This may indicate that temperature inversions increase surface level concentrations of aerosols but have little effect on the total air column. The individual measurements of surface pressure, surface temperature, and wind speed had no observable correlation to AOD (which was less variable than PM2.5 and AQI over the entire year). Elevation was found to have no observable effect on AOD during the period of study. Future research should focus on the relative contributions of different pollutants to the AQI to test if little atmospheric mixing causes the formation of low-altitude secondary pollutants in addition to PM2.5 leading to the observed divergence in AQI and PM2.5.

      Madison Holland
      Analyzing the Transport and Impact of June 2023 Canadian Wildfire Smoke on Surface PM2.5 Levels in Allentown, Pennsylvania
      Madison Holland
      The 2023 wildfire season in Canada was unparalleled in its severity. Over 17 million hectares burned, the largest area ever burned in a single season. The smoke from these wildfires spread thousands of kilometers, causing a large population to be exposed to air pollution. Wildfires can release a variety of air pollutants, including fine particulate matter (PM2.5). PM2.5 directly affects human health – exposure to wildfire-related PM2.5 has been associated with respiratory issues such as the exacerbation of asthma and chronic obstructive pulmonary disease. In June 2023, smoke from the Canadian wildfires drifted southward into the United States. The northeastern United States reported unhealthy levels of air quality due to the transportation of the smoke. In particular, Pennsylvania reported that Canadian wildfires caused portions of the state to have “Hazardous” air quality. Our research focused on how Allentown, PA experienced hazardous levels of air quality from this event. To analyze the concentrations of PM2.5 at the surface level, NASA’s Hazardous Air Quality Ensemble System (HAQES) and the EPA’s Air Quality System (AQS) ground-based site data were utilized. By comparing HAQES’s forecast of hazardous air quality events with recorded daily average PM2.5 with the EPA’s AQS, we were able to compare how well the ensemble system was at predicting total PM2.5 during unhealthy air quality days. NOAA’s Hybrid Single-Particle Lagrangian Integrated Trajectory model, pyrsig, and the Canadian National Fire Database were used. These datasets revealed the trajectory of aerosols from the wildfires to Allentown, Pennsylvania, identified the densest regions of the smoke plumes, and provided a map of wildfire locations in southeastern Canada. By integrating these datasets, we traced how wildfire smoke transported aerosols from the source at the ground level.

      Michele Iraci
      Trends and Transport of Tropospheric Ozone From New York City to Connecticut in the Summer of 2023
      Michele Iraci
      Tropospheric Ozone, or O₃, is a criteria pollutant contributing to most of Connecticut and New York City’s poor air quality days. It has adverse effects on human health, particularly for high-risk individuals. Ozone is produced by nitrogen oxides and volatile organic compounds from fuel combustion reacting with sunlight. The Ozone Transport Region (OTR) is a collection of states in the Northeast and Mid-Atlantic United States that experience cross-state pollution of O₃. Connecticut has multiple days a year where O₃ values exceed the National Ambient Air Quality Standards requiring the implementation of additional monitoring and standards because it falls in the OTR. Partially due to upstream transport from New York City, Connecticut experiences increases in O₃ concentrations in the summer months. Connecticut has seen declines in poor air quality days from O₃ every year due to the regulations on ozone and its precursors. We use ground-based Lidar, Air Quality System data, and a back-trajectory model to examine a case of ozone enhancement in Connecticut caused by air pollutants from New York between June and August 2023. In this time period, Connecticut’s ozone enhancement was caused by air pollutants from New York City. As a result, New York City and Connecticut saw similar O₃ spikes and decline trends. High-temperature days increase O₃ in both places, and wind out of the southwest may transport O₃ to Connecticut. Production and transport of O₃ from New York City help contribute to Connecticut’s poor air quality days, resulting in the need for interstate agreements on pollution management.

      Stefan Sundin
      Correlations Between the Planetary Boundary Layer Height and the Lifting Condensation Level
      Stefan Sundin
      The Planetary Boundary Layer (PBL) characterizes the lowest layer in the atmosphere that is coupled with diurnal heating at the surface. The PBL grows during the day as solar heating causes pockets of air near the surface to rise and mix with cooler air above. Depending on the type of terrain and surface albedo that receives solar heating, the depth of the PBL can vary to a great extent. This makes PBL height (PBLH) a difficult variable to quantify spatially and temporally. While several methods have been used to obtain the PBLH such as wind profilers and lidar techniques, there is still a level of uncertainty associated with PBLH. One method of predicting seasonal PBLH fluctuation and potentially lessening uncertainty that will be discussed in this study is recognizing a correlation in PBLH with the lifting condensation level (LCL). Like the PBL, the LCL is used as a convective parameter when analyzing upper air data, and classifies the height in the atmosphere at which a parcel becomes saturated when lifted by a forcing mechanism, such as a frontal boundary, localized convergence, or orographic lifting. A reason to believe that PBLH and LCL are interconnected is their dependency on both the amount of surface heating and moisture that is present in the environment. These thermodynamic properties are of interest in heavily populated metropolitan areas within the Great Plains, as they are more susceptible to severe weather outbreaks and associated economic losses. Correlations between PBLH and LCL over the Minneapolis-St. Paul metropolitan statistical area during the summer months of 2019-2023 will be discussed.

      Angelica Kusen
      Coupling of Chlorophyll-a Concentrations and Aerosol Optical Depth in the Subantarctic Southern Ocean and South China Sea (2019-2021)
      Angelica Kusen
      Air-sea interactions form a complex feedback mechanism, whereby aerosols impact physical and biogeochemical processes in marine environments, which, in turn, alter aerosol properties. One key indicator of these interactions is chlorophyll-a (Chl-a), a pigment common to all phytoplankton and a widely used proxy for primary productivity in marine ecosystems. Phytoplankton require soluble nutrients and trace metals for growth, which typically come from oceanic processes such as upwelling. These nutrients can also be supplied via wet and dry deposition, where atmospheric aerosols are removed from the atmosphere and deposited into the ocean. To explore this interaction, we analyze the spatial and temporal variations of satellite-derived chl-a and AOD, their correlations, and their relationship with wind patterns in the Subantarctic Southern Ocean and the South China Sea from 2019 to 2021, two regions with contrasting environmental conditions.
      In the Subantarctic Southern Ocean, a positive correlation (r²= 0.26) between AOD and Chl-a was found, likely due to dust storms following Austrian wildfires. Winds deposit dust aerosols rich in nutrients, such as iron, to the iron-limited ocean, enhancing phytoplankton photosynthesis and increasing chl-a. In contrast, the South China Sea showed no notable correlation (r² = -0.02) between AOD and chl-a. Decreased emissions due to COVID-19 and stricter pollution controls likely reduced the total AOD load and shifted the composition of aerosols from anthropogenic to more natural sources.
      These findings highlight the complex interrelationship between oceanic biological activity and the chemical composition of the atmosphere, emphasizing that atmospheric delivery of essential nutrients, such as iron and phosphorus, promotes phytoplankton growth. Finally, NASA’s recently launched PACE mission will contribute observations of phytoplankton community composition at unprecedented scale, possibly enabling attribution of AOD levels to particular groups of phytoplankton.

      Chris Hautman
      Estimating CO₂ Emission from Rocket Plumes Using in Situ Data from Low Earth Atmosphere
      Chris Hautman
      Rocket emissions in the lower atmosphere are becoming an increasing environmental concern as space exploration and commercial satellite launches have increased exponentially in recent years. Rocket plumes are one of the few known sources of anthropogenic emissions directly into the upper atmosphere. Emissions in the lower atmosphere may also be of interest due to their impacts on human health and the environment, in particular, ground level pollutants transported over wildlife protected zones, such as the Everglades, or population centers near launch sites. While rockets are a known source of atmospheric pollution, the study of rocket exhaust is an ongoing task. Rocket exhaust can have a variety of compositions depending on the type of engine, the propellants used, including fuels, oxidizers, and monopropellants, the stoichiometry of the combustion itself also plays a role. In addition, there has been increasing research into compounds being vaporized in atmospheric reentry. These emissions, while relatively minimal compared to other methods of travel, pose an increasing threat to atmospheric stability and environmental health with the increase in human space activity. This study attempts to create a method for estimating the total amount of carbon dioxide released by the first stage of a rocket launch relative to the mass flow of RP-1, a highly refined kerosene (C₁₂H₂₆)), and liquid oxygen (LOX) propellants. Particularly, this study will focus on relating in situ CO₂ emission data from a Delta II rocket launch from Vandenberg Air Force Base on April 15, 1999, to CO₂ emissions from popular modern rockets, such as the Falcon 9 (SpaceX) and Soyuz variants (Russia). The findings indicate that the CO₂ density of any RP-1/LOX rocket is 6.9E-7 times the mass flow of the sum of all engines on the first stage. The total mass of CO₂ emitted can be further estimated by modeling the volume of the plume as cylindrical. Therefore, the total mass can be calculated as a function of mass flow and first stage main engine cutoff. Future CO₂ emissions on an annual basis are calculated based on these estimations and anticipated increases in launch frequency.


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      Last Updated Nov 22, 2024 Related Terms
      General Explore More
      8 min read SARP East 2024 Ocean Remote Sensing Group
      Article 21 mins ago 10 min read SARP East 2024 Hydroecology Group
      Article 21 mins ago 11 min read SARP East 2024 Terrestrial Fluxes Group
      Article 22 mins ago View the full article
    • By NASA
      10 min read
      Preparations for Next Moonwalk Simulations Underway (and Underwater)
      Return to 2024 SARP Closeout Faculty Advisors:
      Dr. Dom Ciruzzi, College of William & Mary
      Graduate Mentor:
      Marley Majetic, Pennsylvania State University

      Marley Majetic, Graduate Mentor
      Marley Majetic, graduate mentor for the 2024 SARP Hydroecology group, provides an introduction for each of the group members and shares behind-the scenes moments from the internship.
      Jordan DiPrima
      How are different land cover types affected by land subsidence on the U.S. Atlantic Coast?
      Jordan DiPrima
      Land subsidence is a frequently overlooked geologic hazard that is caused by natural processes and, more recently, anthropogenic stressors. The goal of this study is to observe subsidence trends and hotspots among land cover types on Virginia’s Eastern Shore and Long Island, New York. This study utilizes interferometric synthetic aperture radar, or InSAR, satellite data from Sentinel-1 to map vertical land motion from 2017 to 2023. Land cover data were sourced from Landsat 8 satellite imagery. Subsidence was mapped within the following land cover types on the Eastern Shore: urban, wetland, cropland, temperate or sub-polar grassland, temperate or sub-polar shrubland, mixed forest, and temperate or subpolar needleleaf forest. These land cover types have mean vertical velocities ranging from -0.2 mm/yr to -5.2 mm/yr. Results suggest that land subsidence is most severe in cropland areas on the Eastern Shore, with a mean vertical velocity of -5.2 mm/yr. In contrast, wetlands display the most subsidence on Long Island with a mean vertical velocity of -2.1 mm/yr. Long Island lacked distinct trends among land cover types and instead showed evidence of subsidence hotspots. These hotspots exist in the following land cover types: temperate or sub-polar grassland, barren lands, wetland, cropland, and temperate or sub-polar broadleaf deciduous forest. Overall, Eastern Shore croplands and Long Island wetlands were determined to be the most susceptible land cover types. These findings highlight regions at risk of sea level rise, flooding, and coastal erosion as a result of subsidence. With further research, we can map subsiding landscapes on a global scale to improve resource allocation and mitigation techniques.

      Isabelle Peterson
      Total Thermokarst Lake Changes on the Seward Peninsula, Alaska: 2016 to 2024
      Isabelle Peterson
      Thermokarst landscapes have and will continue to change as the arctic landscape warms due to climate change. Permafrost underlies much of these arctic landscapes, and as it melts, thermokarst landscapes are left behind. The Seward Peninsula in Alaska has an abundance of these landscapes, and thermokarst lakes are present in the northernmost portion. Several lakes have come and gone, but with increasing climate instability and warming of the area, there is a possibility of more permafrost melting, creating more of these lakes. To capture these changes, Harmonized Landsat Sentinel-2 (HLS) imagery were used to create annual lake maps of the northern portion of the Seward Peninsula from 2016 to 2024. Much of the methodology was informed from Jones et al. (2011); however, their study used eCognition, while the present study used ArcGIS Pro. This caused some differences in results likely due to the differences in software, satellite imagery, and the proposed study area. Lake number changes were observed annually. From this annual change, several 10 to 40 ha lakes disappeared and reappeared within the study period, along with smaller lakes filling in where larger lakes once were. Thermokarst lake drainage is a process described by Jones and Arp (2015) which has devastating geomorphological impacts on the surrounding area, creating large drainage troughs which diminish surrounding permafrost in a quick time frame. To capture these events and overall changes, satellite imagery is essential. This is especially true in remote regions which are hard to reach by foot and require flight missions to be scheduled over the area for aerial photography. However, LVIS and other higher resolution aerial instruments would provide higher accuracy when identifying smaller lakes, as satellite imagery does not accurately capture lakes below 1 ha in the study area. This assertion is made due to conflicting results compared to Jones et al (2011). While the methodologies of this study have been executed manually, Qin, Zhang, and Lu (2023) have proposed the idea of using Sentinel-2 imagery to map thermokarst lakes through automatic methods. While automatization has not yet been perfected, the potential is there and can be used to analyze thermokarst areas effectively. With more satellite imagery, annual, monthly, and potentially daily changes can be captured in favorable months to monitor changing landscapes in arctic regions. Thermokarst lakes have been changing, and monitoring them can help in the process of understanding the changing climate in arctic areas, especially through the lens melting permafrost.

      Emmanelle Cuasay
      Finding Refuge in Climate Crisis: Analyzing the Differences between Refugia and Non-Refugia in the Northern Philippines Using Remote Sensing
      Emmanelle Cuasay
      Refugia are areas that are characterized by stable environmental conditions that can act as a refuge for species as Earth’s climate warms. In this study, fourteen Harmonized Landsat Sentinel-2 images from February 2014 – March 2024 of the northern Philippines region were used. The region of interest is the terrestrial biome by Lake Taal. Normalized Difference Vegetation Index (NDVI) maps were created from all fourteen images to determine the NDVI 25th highest quartiles of the long-term average NDVI images and of a dry and wet year NDVI image. These values were then used to create refugia and non-refugia maps using ArcGIS Pro. Land cover data from Sentinel-2 and a digital elevation model (DEM), using the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), were plotted in ArcGIS Pro to determine the slope and aspect of the area. Global Ecosystems Dynamics Investigation (GEDI) data were used to look at forest height of the study area, and the distribution of forest height, slope, aspect, and elevation were plotted to determine their probability densities in refugia and non-refugia areas. Results of this study show increased biomass in refugia areas. This suggests that conservation practices are crucial to aid in the preservation of biodiversity and biomass within these refugia areas.

      Jayce Crayne
      Site-Based Observations of a Saharan Dust Storm’s Impacts on Evapotranspiration in North-Central Florida
      Jayce Crayne
      Saharan dust storms serve an important role in the western Atlantic’s climate in their contribution to Earth’s radiation budget, modulating sea surface temperatures (SSTs), fertilizing ecosystems, and suppressing cloud and precipitation patterns (Yuan et al., 2020). However, Saharan dust storms are expected to become less frequent in this region as SSTs continue to rise (Yuan et al., 2020). Predicting the climate response to this change requires a keen understanding of how the presence of these storms affect evapotranspiration (ET) and its indicators. This study utilizes site-based observational data from an AmeriFlux tower near Gainesville, FL recorded during a large dust storm in late June 2020. The storm’s progression was documented using satellite imagery from Aqua and Terra and aerosol optical depth (AOD) measurements from an Aerosol Robotic Network (AERONET) station co-located with the AmeriFlux tower. Indicators of ET such as surface air temperature, vapor pressure deficit, photosynthetic photon flux density, and net radiation were analyzed. Findings were compared to modeled ET and latent energy flux reanalysis data provided by the Global Land Data Assimilation System (GLDAS). Both model simulations and on-site observations support that ET decreased during the days dust concentrations were heaviest and for a short time thereafter. Cloud cover data adopted from meteorological aerodrome reports (METARs) provided by an automated surface observing system (ASOS) located in Gainesville showed that clouds were not a major contributor in decreasing ET during the days of heaviest dust. The results of this study show a considerable decrease in ET as a result of dust aerosols. Further research is necessary to determine whether changes in ET due to Saharan dust storms are significant enough to alter climates in the western Atlantic and, if so, what the climate response will be if the frequency of storms decreases.

      Brandon Wilson
      Predicting 2025 and 2028 dNBR and dNDIV for Csarf Smith River Complex / Evaluating the Effects of 2019 California Wildfire Fund
      Brandon Wilson
      Biodiverse regions across California remain vulnerable to harmful wildfires year round. Quantifying and measuring these regions’ wildfire resilience is necessary for understanding where/how to allocate environmental resources. Several ecological wildfire studies have been conducted utilizing artificial intelligence and remote sensing to analyze and predict biodiversity damage across wildfire prone regions, including Northern Algeria and Arkansas, USA. The current case study aims to analyze biodiversity damage from the 2023 Csarf Smith River Complex Fire in Six Rivers National Forest, California and predict the difference in Normalized Burn Ratio (dNBR) and difference in Normalized Difference Vegetation Index (dNDVI) for 2025 and 2028 using remote-sensing-based random forest (RF) regression. Furthermore, to observe, holistically, a practical method California has implemented to address state-wide wildfire damage, the 2019 California Wildfire Fund (AB 1054 and AB 111) was evaluated using the synthetic control method (SCM). For this case study, remote sensing data from the United States Geological Survey (USGS) and NASA (Landsat 9 Satellite C2 L2, TerraClimate and the Land Data Assimilation System) were utilized for processing relevant spectral indexes for the RF. Data from NOAA, Energy Information Agency, International Monetary Fund and Bureau of Economic Analysis were utilized as synthetic control datasets to evaluate the effects of the 2019 California Wildfire Fund. Elevated topography in this study area is susceptible to high severity burn effects, while less elevated topography burns less. This result affected dNBR and dNDVI predictions as elevated areas seemingly did not have strong resilience to rampant burns. This demonstrates a direct correlation to potential lower transpiration rates for elevated areas, warranting further analysis. Results of low variance, post-treatment, between the treated unit and the synthetic control unit, poses concern for the positive effect of the 2019 Wildfire Fund.

      Carrie Hashimoto
      Describing changes in evapotranspiration following the 2020 Creek Fire in the southern Sierra Nevada
      Carrie Hashimoto
      Climatic warming and high tree density have caused larger and more severe wildfires to occur in western United States forests over time. Wildfires affect both the hydrology and ecology of forests via alterations to the water balance (e.g., evapotranspiration, streamflow, infiltration, and more) and could shift vegetation communities and subsequent ecosystem structure and function. This project explores ecological characteristics of a landscape that predict the extent to which the Creek Fire in the southern Sierra Nevada has affected evapotranspiration. Strides in understanding of consequential evapotranspiration changes can create pathways to address emerging forest health challenges posed by similar western fires. For analysis, various remote sensing and modeled data were collected from OpenET, the North American Land Data Assimilation System, TerraClimate, Harmonized LandSat Sentinel-2 data, and the Shuttle Radar Topography Mission. Multiple linear regression and generalized additive models were constructed. Relative change in evapotranspiration served as the response variable. Model covariates included average temperature, total precipitation in the preceding months, average soil moisture, elevation, slope, aspect, northness, latitude, pre-fire normalized difference vegetation index (NDVI), and post-fire change in normalized burn ratio (dNBR). Best subset selection with cross validation demonstrated minimization of cross-validation error with a 7-covariate model. This reduced model yields lower complexity and more interpretability while sustaining an adjusted R2 of 0.626, compared to the full model’s adjusted R2 of 0.663. A reduced generalized additive model (GAM) with interaction terms drawn from the linear model variable selection demonstrated an adjusted R2 of 0.695, indicating a better fit that comes at the cost of reduced interpretability and higher computational requirements than the linear models. The goal of this work is to disentangle environmental indicators of post-fire evapotranspiration change, such that predictive modeling of future wildfire impacts on evapotranspiration can be achieved.


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      Last Updated Nov 22, 2024 Related Terms
      General Explore More
      8 min read SARP East 2024 Ocean Remote Sensing Group
      Article 21 mins ago 10 min read SARP East 2024 Atmospheric Science Group
      Article 21 mins ago 11 min read SARP East 2024 Terrestrial Fluxes Group
      Article 22 mins ago View the full article
    • By NASA
      11 min read
      Preparations for Next Moonwalk Simulations Underway (and Underwater)
      Return to 2024 SARP Closeout Faculty Advisors:
      Dr. Lisa Haber, Virginia Commonwealth University
      Dr. Brandon Alveshere, Virginia Commonwealth University
      Dr. Chris Gough, Virginia Commonwealth University
      Graduate Mentor:
      Mindy Priddy, Virginia Commonwealth University

      Mindy Priddy, Graduate Mentor
      Mindy Priddy, graduate mentor for the 2024 SARP Terrestrial Fluxes group, provides an introduction for each of the group members and shares behind-the scenes moments from the internship.

      Angelina De La Torre
      Using NDVI as a Proxy for GPP to Predict Carbon Dioxide Fluxes
      Angelina De La Torre
      Climate change, driven primarily by greenhouse gases, poses a threat to the future of our planet. Among these gases is carbon dioxide (CO₂), which has a much longer atmospheric residence time compared to other greenhouse gases. One potential factor in reducing atmospheric CO₂ enrichment is plant productivity. Gross Primary Productivity (GPP) estimates the amount of CO₂ fixed during photosynthesis. The Normalized Difference Vegetation Index (NDVI) provides insight into the health of an ecosystem by measuring the density and greenness of vegetation. Therefore, it can be inferred that there is a relationship between NDVI and GPP, as greener plants are likely more productive. In this study, we used NDVI as a proxy for GPP and analyzed the effect NDVI had on CO₂ fluxes during California’s wet season between January and March 2023 in a restored tidal freshwater wetland. GPP and CO₂ flux data were obtained from the Dutch Slough AmeriFlux tower in Oakley, California. Landsat data were used to calculate the average NDVI. The influence of NDVI on GPP was assessed using linear regression. A second linear regression was then performed using NDVI and CO₂ flux, of which GPP is one component. We anticipate that wetlands with greater vegetation density will have lower CO₂ emissions.

      Because Landsat data scans in 16-day intervals, daily variation in NDVI could not be observed. This translates to a frequency discrepancy between the Landsat and AmeriFlux data, as AmeriFlux towers measure in half-hour intervals. Additionally, the wet season represented was limited by data availability, as the data before 2023 were unavailable. Despite data limitations in this study, the outlined process could be repeated in various wetland and climate classifications for further analysis of a larger sample size. This study could assist in developing strategies to increase CO₂ sequestration in an attempt to slow the effects of climate change.

      Samarth Jayadev
      Using Machine Learning to Assess Relationships between NDVI and Net Carbon Exchange During the COVID-19 Pandemic
      Samarth Jayadev
      Understanding the movement of carbon between Earth’s land surface and atmosphere is essential for ecosystem monitoring, creating climate change mitigation strategies, and assessing the carbon budget on national to global scales. Measures of greenness serve as indicators of processes such as photosynthesis that control carbon exchange and are vital in modeling of carbon fluxes. NASA’s Orbiting Carbon Observatory (OCO-2) provides high quality measurements of column-averaged CO₂ concentrations that can be used to derive net carbon exchange (NCE), a measure of CO₂ flux between terrestrial ecosystems and the atmosphere.
      From OCO-2, NCE data collected at the land nadir, land glint satellite position combined with in situ sampling can provide accurate measurements on a 1°x1° scale suitable for carbon flux characterization across the contiguous United States (CONUS). Normalized difference vegetation index (NDVI), which ranges from -1 to +1, measures the greenness of vegetation, serving as an indicator of plant density and health. This can help to understand ecosystem to carbon-cycle interactions and be leveraged for determining patterns with NCE. We examined the relationship between NDVI and NCE across CONUS during 2020 using Gradient Boosting Decision Trees (GBDT) which specialize in classifying and predicting non-linear relationships. This algorithm takes multiple weak learners (decision trees) and combines their predictions in an iterative ensemble method to improve prediction accuracy. Feature and permutation importance tests found that January and August (trough and peak NDVI, respectively) were the highest weighted predictor variables related to NCE. The dataset was split in a 90% training 10% test ratio across latitude/longitude grid cells to assess and verify model performance. Using the mean squared error loss function and hyperparameters with optimal estimators, tree depth, sample split, and learning rate the algorithm was able to converge the test predictions to match the deviance of the training data. The gradient boosting model can be applied to different months and years of NDVI/NCE to further explore these relationships or a multitude of research questions. Further studies should consider integrating land use and land cover change variables such as bare land and urbanization to improve predictions of NCE.

      Makai Ogoshi
      Deep-learning Derived Spaceborne Canopy Structural Metrics Predict Forest Carbon Fluxes
      Makai Ogoshi
      Terrestrial and airborne lidar data products describing canopy structure are potent predictors of forest carbon fluxes, but whether satellite data products produce similarly robust indicators of canopy structure is not known. The assessment of contemporary spaceborne lidar and other remote sensing data products as predictors of carbon fluxes is crucial to next generation instrument and data product design and large-spatial scale modeling. We investigated relationships between deciduous broadleaf forest canopy structure, derived from deep-learning models created with lidar data from GEDI and optical imagery from Sentinel-2, and forest carbon exchange. These included comparisons to in-situ continuous net ecosystem exchange (NEE), gross primary production (GPP), and net primary production (NPP). We find that the mean  canopy height from the gridded spaceborne product has a strong correlation with forest NPP, similar to prior analysis with ground-based lidar (portable canopy lidar; PCL). For comparison to NPP, heights taken from the gridded spaceborne product were compared by overlapping the product with nine terrestrial forest sites from the National Ecological Observatory Network (NEON). We used standard deviation of canopy height as a measure of canopy structural complexity. Complexity derived from the gridded spaceborne product does not show the same strong correlation with NPP as found when using PCL. Mean annual GPP and NEE across five years were compared to the gridded spaceborne product at six Fluxnet2015-tower sites with continuous, gap-filled carbon flux data. When compared to in-situ flux tower data, neither mean canopy height nor structural complexity strongly correlate to annual NEE or GPP. Primarily, the finding that derived spaceborne products exhibit a strong correlation between forest canopy height and NPP will advance global-scale application of forest-carbon flux predictions. Secondarily, a variety of limitations highlight shortcomings in the current terrestrial flux data network. A small number of available study sites, both spatially and temporally, and lack of resolution in vertical complexity of canopy structure both contribute to uncertainty in assessing the relationships to NEE and GPP.

      Sebastian Reed
      Porewater Methane Concentrations Vary Significantly Across A Freshwater Tidal Wetland
      Sebastian Reed
      Methane is a potent greenhouse gas that is over 80 times more powerful than CO₂ at trapping heat and accounts for an estimated 30% of global temperature rise associated with climate change. The largest natural source of methane worldwide is wetlands. Despite the role of methane in driving climate change, the magnitude of global annual wetland methane flux remains highly uncertain. This study analyzes the effects of greenness (assessed using Normalized Difference Vegetation Index; NDVI), plant species composition, rooting depth, atmospheric methane concentration, and plant longevity on porewater methane concentration at the Kimages Rice Rivers Center tidal freshwater wetland. Samples for atmospheric and porewater concentrations were conducted in situ in June 2024. For each sampling location (n = 23) we collected whole air samples (WAS) 2m above the marsh surface and porewater samples 5cm below the marsh surface. We visually assessed species composition at each sample location, with 12 species of wetland plants present overall. We used the TRY plant database to find the rooting depth, leaf nitrogen content, and lifespan of each species. Drone multispectral data from 2023 was used to estimate NDVI values. These variables were compared to the pore water methane concentration via stepwise linear regression. Leaf N content, NDVI, plant species, and WAS sampling did not show statistically significant correlation to porewater methane concentration. Rooting depth showed a slight positive correlation with porewater methane (alpha = 0.1, p = 0.08, R^2 = 0.1). Samples with only perennial plants (as opposed to annual plants) had a higher mean value of porewater methane (p = 0.1). Analyzing porewater methane provides insight as to what wetland components affect methanogenesis and methane release, which aids in assessing which plant functional traits are most responsible for driving or mitigating climate change. Results from this study and future research in this area has the potential to more accurately assess how methane cycles through wetlands to the atmosphere.

      Nohemi Rodarte
      Understanding the vertical profile of CO₂ concentration: How carbon dioxide levels change with altitude
      Nohemi Rodarte
      Carbon dioxide (CO₂) is one of the main greenhouse gasses that contribute to global warming.While the relationship between CO₂ concentrations and land cover types, such as forests and urban areas, is well documented, there is limited knowledge of how CO₂ concentrations vary with altitude at fine spatial scales. Guided by our hypothesis that CO₂ levels vary with altitude and increase with elevation, we used airborne data collected from the B200 aircraft, which flew at different altitudes (400 to 1200 feet) above the urban area of Hopewell, Virginia, between 9:40 AM and 10:40 AM. We analyzed the CO₂ concentrations recorded by the flight to obtain the median and range for each 100 feet of altitude. Our results reveal that carbon dioxide concentrations varied significantly across the range of altitudes investigated. Within the area studied, CO₂ concentrations were found to range between 410 and 470 ppm. The distribution of these concentrations along the altitude gradient shows a bimodal pattern, with notable peaks at altitudes of 700 to 800 feet and 1100 to 1200 feet. Although CO₂ levels were present at all measured altitudes, there was a noticeable drop in the mean concentration at 800 feet,which then stabilized until reaching 1,000 feet before rising again. This pattern indicates that the concentrations of this greenhouse gas are not uniformly distributed with altitude, but rather vary significantly, showing higher concentrations at certain elevations and lower concentrations at others. The CO₂ distribution fluctuates with altitude, showing higher or lower levels at specific heights rather than a smooth gradient, indicating that altitude impacts CO₂ concentrations. While we did not identify the drivers of this change, future studies could evaluate how factors such as surface emissions, atmospheric mixing, and local conditions may contribute to vertical CO₂ profiles, since the altitudes we considered in this research are within the troposphere.

      Camille Shaw
      Linking NDVI with CO₂ and CH₄ Fluxes: Insights into Vegetation and Urban Source-Sink Dynamics in the Great Dismal Swamp
      Camille Shaw
      In recent years, carbon dioxide, methane, and other greenhouse gases have gained attention because of their contribution to the rise in Earth’s global mean temperature. Methane and carbon dioxide have various sources and sinks, but an expanding array of sources have created a need to assess ongoing change in carbon balance. This study aims to quantify the relationship between Normalized Difference Vegetation Index, or NDVI, and methane and carbon dioxide fluxes. We measured carbon dioxide and methane concentrations within the boundary layer using the PICARRO instrument, focusing on the Great Dismal Swamp, a forested wetland, and surrounding areas in the Eastern Mid-Atlantic Region. Data collection occurred at various times of day and along different flight paths in 2016, 2017, and 2024, with each year representing data from a single season, either spring or fall, for temporal analysis. We calculated methane and carbon dioxide fluxes along the flight paths using airborne eddy covariance, a method for capturing accurate flux measurements while accounting for the mixing of gases in the boundary layer caused by heat. Additionally, we calculated NDVI for this area using NASA’s Landsat 8 and 9 satellite imagery. Analysis of the afternoon flight data revealed a negative linear correlation between NDVI and carbon dioxide flux. Urban areas, characterized by low NDVI, exhibit a positive carbon dioxide flux as a consequence of emissions from vehicles, while forested areas, with high NDVI, show a negative carbon dioxide flux because of photosynthesis. In contrast, methane flux shows minimal correlation with NDVI. The lack of correlation arises because forested wetlands, with high NDVI, emit substantial amounts of methane, while urban areas, despite having low NDVI, still produce significant methane emissions from landfills and industrial activities. Future research could further investigate how seasonal and diurnal variations influence the correlations between NDVI and greenhouse gases by collecting comprehensive data across all seasons within a given year and at various times of the day.

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