Members Can Post Anonymously On This Site
-
Similar Topics
-
By European Space Agency
A new European Space Agency-backed study shows that the extreme heatwaves of 2023, which fuelled huge wildfires and severe droughts, also undermined the land’s capacity to soak up atmospheric carbon. This diminished carbon uptake drove atmospheric carbon dioxide levels to new highs, intensifying concerns about accelerating climate change.
View the full article
-
By NASA
Earth Observer Earth Home Earth Observer Home Editor’s Corner Feature Articles Meeting Summaries News Science in the News Calendars In Memoriam More Archives 22 min read
NASA’s BlueFlux Campaign Supports Blue Carbon Management in South Florida
Photo 1. A Mangrove stand lines the bank of Shark River, an Everglades distributary that carries water into the Gulf of Mexico’s Ponce De Leon Bay. Photo credit: Nathan Marder/NASA’s Goddard Space Flight Center (GSFC) Introduction
Along the southernmost rim of the Florida Peninsula, the arching prop roots or “knees” of red mangroves (Rhizophora mangle) line the coast – see Photo 1. Where they dip below the water’s surface, fish lay their eggs, enjoying the protection from predators that the trees provide. Among their branches, wading birds, such as the great blue heron and the roseate spoonbill establish rookeries to rear their young. The tangled matrix of roots collects organic matter and ocean-bound sediments, adding little-by-little to the coastline and shielding inland biology from the erosive force of the sea. In these ways, mangroves are equal parts products and engineers of their environment, but their ecological value extends far beyond this local sphere of influence.
Mangroves are an important carbon dioxide (CO2) sink – responsible for removing CO2 from the atmosphere with impressive efficiency. Current estimates suggest mangroves sequester CO2 10 times faster and store up to 5 times more carbon than rainforests and old-growth forests. But as part of the ever-changing line between land and sea, they’re exceptionally vulnerable to climate disturbances such as sea level rise, hurricanes, and changes in ocean salinity. As these threats intensify, Florida’s sub-tropical wetlands – and their role as a critical sink of CO2 – face an uncertain future.
NASA’s BlueFlux Campaign, a three-year (2021–2024), $1.5-million project operating under the agency’s Carbon Monitoring System, used field, aircraft, and satellite data to study the impact of both natural and anthropogenic pressures on South Florida’s coastal ecology. BlueFlux consists of a series of ground-based and airborne fieldwork campaigns, providing a framework for the development of a satellite-based data product that will estimate daily rates of surface-atmosphere gas transfer or gaseous flux across coastal ecosystems in Florida and the Caribbean. “The goal is to enhance our understanding of how blue-carbon ecosystems fit into the global carbon market,” said Ben Poulter [NASA’s Goddard Space Flight Center (GSFC)—Project Lead]. “BlueFlux will ultimately answer scientific questions and provide policy-related solutions on the role that coastal wetlands play in reducing atmospheric greenhouse gas (GHG) concentrations.”
This article provides an overview of BlueFlux fieldwork operations – see Figure 1 – and outlines how the project might help refine global GHG budgets and support the restoration of Florida’s wetland ecology.
Figure 1. A map of South Florida overlaying a true-color image captured by the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on board NASA’s Terra satellite. Red triangles mark locations of primary ground-based fieldwork operations described in this article. Figure Credit: NASA’s Goddard Space Flight Center (GSFC) BlueFlux Ground-based Fieldwork
Across the street from the Flamingo Visitors center, at the base of the Everglades National Park, there was once a thriving mangrove population. Now, the skeletal remains of the trees form one of the Everglades’ largest ghost forests – see Photo 2. When Hurricane Irma made landfall in September 2017, violent winds battered the shore and a storm surge swept across the coast, decimating large swaths of the mangrove forest. Most of Florida’s mangroves recovered swiftly. But seven years later, this site and others like it have seen little to no growth.
“At this point, I doubt they’ll ever recover,” said David Lagomasino [East Carolina University].
Photo 2. A mangrove ghost forest is all that remains of a once-thriving mangrove stand, preserving an image of Hurricane Irma’s lasting impact on South Florida’s wetland ecology. Most of the ghost forests in the region are a product of natural depressions in the landscape that collect saltwater following severe storms. Photo credit: Nathan Marder/NASA’s Goddard Space Flight Center (GSFC) Lagomasino was in the Everglades this summer conducting research as part of the fifth leg of BlueFlux fieldwork – see Photo 3. His team focused on measuring how changes in wetland ecology affect the sequestration and emission rates of both CO2 and methane (CH4). In areas where vegetative health is severely degraded, like in ghost forests, a general decline in CO2 uptake is accompanied by an increase in CH4 production, the net effect of which could dramatically amplify the atmosphere’s ability to trap heat. Ghost forests offer an example at one end of an extreme, but defining the way more subtle gradients among wetland variables – such as changes in water level, tree height, canopy coverage, ocean salinity, or mangrove species distribution – might influence flux is harder to tease out of the limited data available.
Photo 3. Assistant professor David Lagomasino and Ph.D. candidate Daystar Babanawo [both from East Carolina University] explore the lower Everglades by boat. Due to the relative inaccessibility of the region, measurements of flux in wetland ecosystems are limited. The plant life here consists almost entirely of Florida’s three Mangrove species (red, black, and white), which are among the only vegetation that can withstand the brackish waters characteristic of coastal wetlands. Photo credit: Nathan Marder/NASA’s Goddard Space Flight Center (GSFC) In the Everglades, flux measurements are confined to a handful of eddy covariance towers – or flux towers – constructed as part of the National Science Foundation’s (NSF) Long-Term Ecological Research (LTER) Network.
The first flux tower in this network, erected in June 2003, stands near the edge of Shark River at a research site called SRS-6, short for Shark River Slough site 6. A short walk from the riverbank, across a snaking path of rain-weathered, wooden planks, sits a small platform where the flux tower is anchored to the forest floor – see Photo 4. About 20 m (65 feet) above the platform, the tower breaches the canopy, where a suite of instruments continuously measures wind velocity, temperature, humidity, and the vertical movement of trace atmospheric gases, such as water vapor (H2Ov), CO2, and CH4. It’s these measurements collectively that are used to calculate flux.
Photo 4. At SRS-6, an eddy covariance tower measures C02 and CH4 flux among a dense grove of red, black, and white mangroves. The term eddy covariance refers to the statistical technique used to calculate gaseous flux based on the meteorological and scalar atmospheric data collected by the flux towers. Photo credit: Nathan Marder/NASA’s Goddard Space Flight Center (GSFC) “Hundreds of research papers have come from this site,” said Lagomasino. The abundance of research generated from the data captured at SRS-6 speaks in part to the value of the measurements that the tower makes. It also points to the gaps that exist just beyond each tower’s reach. A significant goal of the BlueFlux campaign is to explain flux on a scale that isn’t covered by existing data – to fill in the gaps between the towers.
One way to do that is by gathering data by hand.
On Lagomasino’s boat is a broad, black case carrying a tool called a Russian peat auger. The instrument is designed to extract core samples from soft soils – see Photo 5.
Everglades peat, which is made almost entirely of the partially decomposed roots, stems, and leaves of the surrounding mangroves, offers a perfect study subject. Each thin, half-cylinder sample gets sealed and shipped back to the lab, where it will be sliced into flat discs. The discs will be analyzed for their age and carbon content by Lagomasino’s team and partners at Yale University. These cores are like biomass time capsules. In Florida’s mangrove forests, a 1-m (3-ft) core might represent more than 300 years of carbon accumulation. On average, a 1 to 3 mm (0.04 to 0.12 in) layer of matter is added to the forest floor each year, building up over time like sand filling an hourglass.
Photo 5. David Lagomasino holds a Russian peat auger containing a sample of Everglades peat. The primary source of the soil’s elevated carbon content – evident from its coarse, fibrous texture – is the partially decayed plant tissue of the surrounding mangroves. Photo credit: Nathan Marder/NASA’s Goddard Space Flight Center (GSFC) Although coastal wetlands account for less than 2% of the planet’s land-surface area, they house a disproportionate amount of blue carbon – carbon stored in marine and coastal environments. In the Everglades, the source of this immense accumulation of organic material is the quick-growing vegetation – see Photo 6.
When a CO2 molecule finds its way through one of the many small, porous openings on a mangrove leaf – called stomata – its next step is one of creation, where it plays a part in the miraculous transformation of inorganic matter into living tissue. Inside the leaf’s chloroplasts, energy from stored sunlight kickstarts a long chain of chemical reactions that will ultimately divide CO2 into its constituent parts. Oxygen atoms are returned to the atmosphere as the byproduct of photosynthesis, but the carbon stays behind to help build the sugar molecules that will fuel new plant growth. In short, the same carbon that once flowed through the atmosphere defines the molecular structure of all wetland vegetation. When a plant dies or a gust of wind pulls a leaf to the forest floor, this carbon-based matter finds its way into the soil, where it can stay locked in place for thousands of years thanks to a critical wetland ingredient: water.
The inundated, anoxic – an environment deficient or absent of oxygen – peat soils characteristic of wetlands host microbial populations that are uniquely adapted to their environment. In these low- to no-oxygen conditions, the prevailing microbiota consumes organic material slowly, leading to an accumulation of carbon in the soil. As wetland conditions change, the soil’s microbial balance shifts. For example, a decline in water level, which can increase the oxygen-content of the soil, produces conditions favorable to aerobic bacteria. These oxygen-breathing lifeforms consume organic matter far more rapidly than their anaerobic counterparts – and release more CO2 into the atmosphere as a result.
Water level isn’t the only environmental condition that influences rates of carbon sequestration. The soil cores collected during the campaign will be analyzed alongside records of interrelated variables such as water salinity, sea surface height, and temperature to understand not just the timescales associated with blue carbon development in mangrove forests but how and why rates of soil deposition change in response to specific environmental pressures. In many parts of the Everglades, accumulated peat can reach depths of up to 3 m (9.8 feet) – holding thousands of years’ worth of insights that would otherwise be lost to time.
Photo 6. Mangroves are viviparous plants. Their propagules – or seedlings – germinate while still attached to their parent tree. Propagules that fall to the forest floor are primed to begin life as soon as they hit the ground. But even those that fall into bodies of water and are carried out to sea can float for months before finding a suitable place to lay their roots. The high growth rate of mangroves contributes to the efficiency with which mangrove forests remove CO2 from the atmosphere. Photo credit: Nathan Marder/NASA’s Goddard Space Flight Center (GSFC) Lola Fatoyinbo [NASA’s Goddard Space Flight Center (GSFC), Biospheric Sciences Lab] and Peter Raymond [Yale University’s School of the Environment] led additional fieldwork teams tasked with collecting forest inventory data in locations where vegetation was dead, regenerating, or recently disturbed by severe weather events. A terrestrial laser system was used to obtain three-dimensional (3D) images of mangrove forest structure, which provided maps of stem density, vertical distributions of biomass, and stand volume surface area. Spectroradiometers were also used to acquire visible, near infrared, and shortwave infrared spectra, delivering detailed information about species composition, vegetative health, water levels, and soil properties.
To tie these variables to flux, the researchers made measurements using chambers – see Figure 2 – designed to adhere neatly to points where significant rates of gas exchange occur, (i.e., mangrove lenticels—cell-sized breathing pores found on tree bark and root systems— and the forest floor). As an example, black mangroves (Avicennia germinans) possess unique aerial roots called pneumatophores that, similar to the prop roots of red mangroves, provide them with access to atmospheric oxygen. Pneumatophores sprout vertically from the forest floor and line up like matchsticks around the base of each tree. The team used cylindrical chambers to measure the transfer of gas between a single pneumatophore and the atmosphere – see Figure 2a.
These observations are archived in NASA’s Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC) and publicly available to researchers who wish to monitor and identify trends in the data. After nearly three years of field work, these data have already given scientists a more detailed picture of how Florida’s wetlands are responding to environmental pressures.
Research based on data from early BlueFlux fieldwork deployments confirms that aerobic, methanogenic microbes living in flooded, wetland soils naturally release a significant amount of CH4 as a byproduct of the process by which they create their own energy.
“We’re especially interested in this methane part,” said Fatoyinbo. “It’s the least understood, and there’s a lot more of it than we previously thought.” Fatoyinbo also noted a “significant difference in CO2 and CH4 fluxes between healthy mangroves and degraded ones.” In areas where mangrove health is in decline, due to reduced freshwater levels or as the result of damage sustained during severe weather events, “you can end up with more ‘bad’ gases in the atmosphere,” she said. Since CH4 is roughly 80 times more potent than CO2 over 100-year period, these emissions can undermine some of the net benefits that blue carbon ecosystems provide as a sink of atmospheric carbon.
Figure 2. To directly measure the emission and sequestration rates of CO2 and CH4 in mangrove forests, chambers were designed to adhere to specific targets where gas exchange occurs (i.e. mangrove lenticles, root systems, and the forest floor). Credit: GSFC Airborne Research Teams Measure GHG Flux from Above
Florida’s mangrove forests blanket roughly 966 km2 (600 mi2) of coastal terrain. Even with over 20 years of tower data and the extensive measurements from ground-based fieldwork operations, making comprehensive inferences about the entire ecosystem is tenuous work. To provide flux data at scale – and help quantify the atmospheric influence that Florida’s coastal wetlands carry as a whole – NASA’s BlueFlux campaign relies on a relatively new, airborne technique for measuring flux – see Photo 7.
Photo 7. At the Miami Executive Airfield, members of NASA’s BlueFlux airborne science team stand in front of the Beechcraft 200 King Air before the final flight of the fieldwork campaign. Photo credit: Nathan Marder/NASA’s Goddard Space Flight Center (GSFC) Between 2022 and 2024, over 5 deployments, the team conducted more than 34 carefully planned flights – see Figure 3 – collecting flux data over Florida’s wetlands by plane. Each flight is equipped with a payload known colloquially as “CARAFE,” short for the CARbon Airborne Flux Experiment, which is the airborne campaign’s primary means of data collection. “This is one of the first times an instrument like this has flown over a mangrove forest anywhere in the world,” said Fatoyinbo. “So, it’s really just kind of groundbreaking.”
Figure 3. An example of flight paths from eight BlueFlux airborne deployments flown in April 2023. The flight paths are highlighted in blue. The legs of each flight where flux measurements were taken are highlighted in green. Accurate flux calculations rely on stable measurements of the aircraft’s speed and orientation, which is why the flux legs of each flight are flown in straight lines. Credit: GSFC In the air, GHG concentrations are measured using a well-established technique called cavity ringdown spectroscopy, which involves firing a laser into a small cavity where it will ping back and forth between two highly reflective mirrors. Most gas-phase molecules absorb light at specific wavelengths, depending on their atomic makeup. Since the target molecules in this case are CO2 and CH4, the laser is configured to emit light at a wavelength that only these molecules will absorb. As the laser bounces between the mirrors, a fraction of the light is absorbed by any molecules present in the chamber. The rate of the light’s decay is used to estimate CO2 and CH4 concentrations, generating a time series with continuous readings of gas concentrations, measured in parts per million – see Photo 8. This information is combined with measurements of vertical wind velocity to calculate a corresponding time series of fluxes along the flight track. While these measurements are important on their own, a priority for the airborne team is understanding GHG fluxes in relation to what’s happening on the ground.
Photo 8. The CARAFE payload is responsible for taking readings of atmospheric CO2, CH4, and H2Ov levels using a wind probe and two optical spectroscopy instruments manufactured by Picarro: the G2401m Gas Concentration Analyzer and the G2311f Gas Concentration Analyzer. The readings pictured above were made by the G2311f, which measures gas concentrations at a faster rate than the G2401m. The G2401m makes slower but more stable measurements, which are necessary for verifying the accuracy of measurements made by the G2311f. Photo credit: Nathan Marder/NASA’s Goddard Space Flight Center (GSFC) Unlike flux towers, which only collect data within a 100 m2 (328 ft2) “footprint,” airborne readings have a footprint that can stretch up to 1 km (0.6 mi) in upwind directions. The plane’s speed, position, and orientation are used to help link flux data to fixed points along the flight’s path – so the team can make comparisons between aerial measurements and those made by the ground-based towers – see Photo 9.
“One challenge with that is the flux towers are much lower to the ground, and their footprint is much smaller,” said Glenn Wolfe [GSFC—BlueFlux Flight Lead]. “So, we have to be really careful with our airborne observations, to make sure they closely resemble our ground-based measurements.”
Part of decoding the airborne data involves overlaying each footprint with detailed maps of different surface properties, such as vegetation cover, soil water depth, or leaf-area index, so the team can constrain the measurements and assign fluxes to specific sources – whether its mangroves, sawgrass, or even water.
Photo 9. The BlueFlux airborne science team collects flux measurements from 90m (300ft) above Florida’s mangrove forests. Photo credit: Nathan Marder/NASA’s Goddard Space Flight Center (GSFC) Data Upscaling – Making Daily Flux Predictions from Space
The coupling of BlueFlux’s ground-based and airborne data provides the framework for the production of a broader, regional image of GHG flux.
“The eddy flux towers give us information about the temporal variability,” said Cheryl Doughty [GSFC]. “And the airborne campaign gives us this great intermediate dataset that allows us to go from individual trees to a much larger area.”
Doughty is now using BlueFlux data to train a remote-sensing data product, the prototype of which is called Daily Flux Predictions for South Florida. The product’s underlying model relies on machine learning algorithms and an ensemble modeling technique called random forest regression. It will make flux predictions based on surface reflectance data captured by the Moderate Resolution Imaging Spectroradiometer (MODIS), an instrument that flies on NASA’s polar-orbiting Aqua and Terra satellites – see Figure 4.
“We’re really at the mercy of the data that’s out there,” said Doughty. “One of the things we’re trying to produce as part of this project is a daily archive of fluxes, so MODIS is an amazing resource, because it has over 20 years of data at a daily temporal resolution.”
This archival flux data will help researchers explain how fluxes change in relation to processes that are directly described by MODIS surface reflectance data, including sea-level rise, land use, water management, and disturbances from hurricanes and fires.
Figure 4. Sample of methane flux upscaling, in which MODIS surface reflectance retrievals are used to predict CH4 flux for South Florida at a regional scale [bottom row, left]. The model inputs rely on a composite of MODIS Nadir Bidirectional Reflectance Distribution Function (BRDF)-Adjusted Radiance (NBAR) measurements from all available MODIS land bands: [top row, left to right]: red (620–670 nm), green (545–565 nm), blue (459–479 nm); [middle row, left to right] near infrared 1, or NIR1 (841–876 nm), NIR2 (1230–1250 nm), shortwave IR 1, or SWIR1 (1628–1652 nm), and SWIR 2 (2105–2155 nm). The Everglades National Park boundary is indicated on each image with a white line. Output of the model is shown [bottom row, left] as well as a comparison between modeled fluxes of MODIS NBAR with Terra and Aqua [bottom row, right]. Credit: GSFC To help validate the model, researchers must reformat flux measurements from the airborne campaign to match the daily temporal resolution and 500m2 (0.3mi2) spatial resolution of MODIS reflectance retrievals.
“It’s best practice to meet the data at the coarsest resolution,” said Doughty. “So, we have to take an average of the hourly estimates to match MODIS’ daily scale.”
The matching process is slightly more complicated for spatial datasets. BlueFlux’s airborne flux measurements produce roughly 20 data points for each 500 m2 (0.3 mi2) area, the same resolution as a single MODIS pixel.
“We’re essentially taking an average of all those CARAFE points to get an estimate that corresponds to one pixel,” said Doughty.
This symmetry is critical, allowing the team to test, train, and tune the model using measurements that capture what’s really happening on the ground – ensuring the accuracy of flux measurements generated from satellite data alone.
Researchers don’t expect the model to serve as a perfect reconstruction of reality. The heterogenous nature of Florida’s wetland terrain – which consists of a patchwork of sawgrass marshland, mangrove forests, hardwood hammocks, and freshwater swamps – contributes to high degree of variability in CO2 removal rates within and across its distinct regions. The daily flux product accounts for some of this complexity by making hundreds of calculations at a time, each with slightly different parameters based on in-situ measurements.
“The goal isn’t to just give people one flux measurement but an estimate of the uncertainty that is so inherent to these wetlands,” explained Doughty.
The prototype of the product will be operational by early 2025 and accessible to the public through NASA’s ORNL DAAC. Doughty hopes it will help stakeholders and decision makers evaluate policies related to water management, land use, and conservation that might impact critical stocks of blue carbon.
From Drainage to Restoration in the Florida Everglades
In the late 19th century, land developers were drawn to South Florida, where they hoped the fertile soil and tropical climate could support year-round cultivation of commodities such as exotic fruits, vegetables, and sugar cane. There was just one thing standing in the way – the water. If they could find a way to tame Florida’s wilderness, to drain the wetland of its excess water, Florida would offer Americans a new agricultural frontier.
Progress was made incrementally, but the Everglades drainage project idled for more than 50 years as its organizers wrestled with the literal and political morass surrounding South Florida’s wetland topography. It was mother nature’s hand that ultimately accelerated the drainage project. In 1926 and 1928, two large hurricanes tore through the barrier along Lake Okeechobee’s southern shore built to prevent water from spilling onto the newly settled, small-scale farmland just south of the lake. The second of the two storms – 1928’s Okeechobee Hurricane – made landfall in early September and resulted in nearly 3,000 recorded fatalities. In some areas, the torrent of flood water was deep enough that even those who sought refuge from the flood on the roofs of their homes were swept away by the current. The federal government was forced to step in.
By 1938, the U.S. Army Corps of Engineers had completed construction of the Hoover Dike, adding to a collection of four canals responsible for siphoning water away from Lake Okeechobee’s floodplain and into the Atlantic Ocean. Seasonal flooding was brought under control, but the complete reclamation of South Florida’s wetlands proved more challenging than anticipated. As water levels fell and freshly cleared lands dried out, the high organic content of the soil fueled tremendous peat and muck fires that could burn for days, spreading through underground seams where water once flowed. In some areas, fires consumed the entire topsoil layer – exposing the limestone substrata to the atmosphere for the first time in thousands of years. The engineers in charge of Florida’s early wetland reclamation projects underestimated the value of the state’s hydrological system and overestimated its capacity to withstand human interference.
“Those initial four canals were enough to drain the everglades three times over,” said Fred Sklar [South Florida Water Management District—Everglades System Sciences Director]. “And they still exist, but now there are more than seven million people who rely on them for drinking water and flood control.”
Today, much of the Water Management District’s work involves unwinding the damage wrought by earlier drainage efforts.
“One thing we’re trying to do is make sure these peat fires never happen again,” said Sklar.
But restoring natural water flow to the Everglades – which is critical to the region’s ecological health – isn’t an option. Even if drainage could be reversed, it would subject Florida’s residents to the same flood risks that made drainage a priority. Some residents, including members of the Miccosukee and Seminole tribes, live directly alongside or within Everglades wilderness areas, where the risk of flooding is even greater than it is in the state’s highly populated coastal communities. These areas are also out of reach of the Water Management District’s existing infrastructure. It’s not as simple as turning the tap on and off.
Photo 10. The Tamiami Trail Canal runs across the Florida Peninsula from west to east, towards a saltwater treatment facility near the Miami River. Construction was completed in 1928, shortly after the first four drainage canals opened. It quickly became apparent that the canal and its adjacent roadway dramatically impede water flow to the Everglades wilderness areas to their south, cutting off the region’s vegetation and wildlife from a critical source of freshwater. New modifications to the canal are currently underway, which aim to introduce a hydrological regime that more closely resembles the pre-drainage system. Photo credit: U.S. National Park Service Florida’s Water Management District works with federal agencies, including the U.S. Army Corps of Engineers, to monitor and govern the flow of Florida’s freshwater. The District has overseen the construction and management of dozens of canals, dikes, levees, dredges, and pumps over the last half-century that offer a higher degree of control over Florida’s complex hydrological network – see Photo 10.
“The goal is to restore as much acreage as we can, but we also need to restore it functionally, without degrading the whole system or putting residents at risk,” summarized Sklar. “To do this effectively, we need a detailed understanding of how the hydrology functions and how it influences all of these other systems, such as carbon sequestration.”
Since the 1920s, more than half of Florida’s original wetland coverage has been lost. The present system also carries 65% less peat coverage and 77% less stored carbon than it did prior to drainage. As atmospheric CO2 concentrations climb at unprecedented rates, an accompanying rise in sea levels, severe weather, and ocean salinity all present serious threats to Florida’s wetland ecology – see Figure 5.
“We’re worried about losing that stored carbon,” said Poulter. “But blue carbon also offers tremendous opportunities for climate mitigation if conservation and restoration are properly supported by science.”
Figure 5. A map of the BlueFlux study region, showing mangrove extent (green) and the paths of tropical storms and hurricanes from 2011 to 2021 (red). These storms drive losses in mangrove forest coverage – the result of erosion and wind damage. The inset regions at the top of the image highlight proposed targets for the airborne component of NASA’s BlueFlux Campaign. Figure credit: GSFC Conclusion – The Future of Flux
Every few years, the Intergovernmental Panel on Climate Change (IPCC) releases emissions data and budget reports that have important policy implications related to the Paris Agreement’s goal of limiting global warming to between 1.5°C (2.7°F) and 2°C (3.6°F) compared to pre-industrial levels. Refining the accuracy of global carbon budgets is paramount to reaching that goal, and wetland ecosystems – which have been historically under-represented in climate research – are an important part of the equation.
Early estimates based on BlueFlux fieldwork deployments and upscaled using MODIS surface reflectance data suggest that wetland CH4 emissions in South Florida offset CO2 removal in the region by about 5% based on a 100-year CH4 warming potential, resulting in a net annual CO2 removal of 31.8 Tg (3.18 million metric tons) per year. This is a small fraction of total CO2 emissions in the U.S. and an even smaller fraction of global emissions. In 2023, an estimated 34,800 Tg (34.8 billion metric tons) of CO2 were released into the atmosphere. But relative to their size, the CO2 removal services provided by tropical wetlands are hardly dismissible.
“We’re finding that massive amounts of CO2 are removed and substantial amounts of CH4 are produced, but overall, these ecosystems provide a net climate benefit by removing more greenhouse gases than they produce,” Poulter said.
Access to a daily satellite data product also provides researchers with the means to make more regular adjustments to budgets based on how Florida’s mutable landscape is responding to climate disturbances and restoration efforts in real time.
With the right resources in hand, the scientists who dedicate their careers to understanding and restoring South Florida’s ecology share a hopeful outlook.
“Nature and people can absolutely coexist,” said Meenakshi Chabba [The Everglades Foundation—Ecologist and Resilience Scientist]. “But what we need is good science and good management to reach that goal.”
The Everglades Foundation provides scientific evaluation and guidance to the elected officials and governmental institutions responsible for the implementation of the Comprehensive Everglades Restoration Plan (CERP), a federal program approved by Congress in 2000 that outlines a 30-year plan to restore Florida’s wetland ecology. The Foundation sees NASA’s BlueFlux campaign as an important accompaniment to that goal.
“The [Daily Flux Predictions for South Florida] data product is incredibly valuable, because it provides us with an indicator of the health of the whole system,” said Steve Davis [The Everglades Foundation—Chief Science Officer]. “We know how valuable the wetlands are, but we need this reliable science from NASA and the BlueFlux Campaign to help translate those benefits into something we can use to reach people as well as policymakers.”
Researchers hope the product can inform decisions about the management of Florida’s wetlands, the preservation of which is not only a necessity but – to many – a responsibility.
“These impacts are of our own doing,” added Chabba. “So, now it’s incumbent upon us to make these changes and correct the mistakes of the past.”
Next, the BlueFlux team is shifting their focus to what they call BlueFlux 2. This stage of the project centers around further analysis of the data collected during fieldwork campaigns and outlines the deployment of the beta version of Daily BlueFlux Predictions for South Florida, which will help generate a more accurate evaluation of flux for the many wetland ecosystems that exist beyond Florida’s borders.
“We’re trying to contribute to a better understanding of global carbon markets and inspire further and more ambitious investments in these critical stocks of blue carbon,” said Poulter. “First, we want to scale this work to the Caribbean, where we have these great maps of mangrove distribution but limited data on flux.”
An additional BlueFlux fieldwork deployment is slated for 2026, with plans to make flux measurements above sites targeted by the state for upcoming restoration initiatives, such as the Everglades Agricultural Area Environmental Protection District. In the Agricultural Area, construction is underway on a series of reservoirs that will store excess water during wet seasons and provide a reserve source of water for wildlife and residents during dry seasons. As the landscape evolves, BlueFlux will help local officials evaluate how Florida’s wetlands are responding to efforts designed to protect the state’s most precious natural resource – and all those who depend on it.
Nathan Marder
NASA’s Goddard Space Flight Center/Global Science and Technology Inc.
nathan.marder@nasa.gov
Share
Details
Last Updated Nov 12, 2024 Related Terms
Earth Science View the full article
-
By NASA
Earth Observer Earth Home Earth Observer Home Editor’s Corner Feature Articles Meeting Summaries News Science in the News Calendars In Memoriam More Archives 22 min read
Summary of the Second OMI–TROPOMI Science Team Meeting
Introduction
The second joint Ozone Monitoring Instrument (OMI)–TROPOspheric Monitoring Instrument (TROPOMI) Science Team (ST) meeting was held June 3–6, 2024. The meeting used a hybrid format, with the in-person meeting hosted at the National Center for Atmospheric Research (NCAR) in Boulder, CO. This was the first OMI meeting to offer virtual participation since the COVID-19 travel restrictions. Combining the onsite and virtual attendees, the meeting drew 125 participants – see Photo.
OMI flies on NASA’s Earth Observing System (EOS) Aura platform, launched July 15, 2004. TROPOMI flies on the European Space Agency’s (ESA)–Copernicus Sentinel-5 Precursor platform. OMI has collected nearly 20 years of data and TROPOMI now has amassed 5 years of data.
Meeting content was organized around the following four objectives:
discussion of the final reprocessing of OMI data (called Collection 4) and of data preservation; discussion of OMI data continuity and enhancements using TROPOMI measurements; development of unique TROPOMI products [e.g., methane (CH4)], applications (e.g., tracking emissions – and using them as indicators of socioeconomic and military activities), and new focus regions (e.g., Africa); and leverage synergies between atmospheric composition (AC) and greenhouse gas (GHG) missions, which form the international constellation of low Earth orbit (LEO) and geostationary orbit (GEO) satellites. The remainder of this article summarizes the highlights from each day of the meeting.
Photo. Group photo of the in-person participants at the OMI–TROPOMI Science Team meeting. Photo credit: Shaun Bush/NCAR’s Atmospheric Chemistry Observations & Modeling DAY ONE
The topics covered on the first day of the meeting included OMI instrument performance, calibration, final Collection 4 reprocessing, and plans for data preservation.
OMI and Data Products Update
Pieternel Levelt [Royal Netherlands Meteorological Institute (KNMI)—OMI Principal Investigator (PI) and NCAR’s Atmospheric Chemistry Observations & Modeling (ACOM) Laboratory—Director] began her presentation by dedicating the meeting to the memory of Johan de Vries, whose untimely death came as a shock to the OMI and TROPOMI teams – see In Memoriam: Johan de Vries for a celebration of his accomplishments and contributions to the OMI-TROPOMI team. She then went on to give a status update on OMI, which is one of two currently operating instruments on EOS Aura [the other being the Microwave Limb Sounder (MLS)]. OMI is the longest operating and stable ultraviolet–visible (UV-VIS) spectrometer. It continues to “age gracefully” thanks to its design, contamination control measures undertaken after the launch, and stable optical bench temperature. Lessons learned during integration of OMI on the Aura spacecraft (e.g., provide additional charged couple device shielding) and operations (i.e., monitor partial Earth-view port blockages) guided the development and operations of the follow-on TROPOMI mission.
Continued monitoring of OMI performance is crucial for extending science- and trend-quality OMI records to the end of the Aura mission (currently expected in 2026). Antje Ludewig [KNMI] described the new OMI Level-1B (L1B) processor (Collection 4), which is based on TROPOMI data flow and optimized calibrations. The processor has been transferred to the U.S. OMI ST, led by Joanna Joiner [NASA’s Goddard Space Flight Center (GSFC)]. Matthew Bandel [Science Systems and Applications, Inc. (SSAI)] described NASA’s new OMI monitoring tools.
Sergey Marchenko [SSAI] discussed OMI daily spectral solar irradiance (SSI) data, which are used for monitoring solar activity and can be compared with the dedicated Total and Spectral Solar Irradiance Sensor (TSIS-1) on the International Space Station. Continuation of OMI measurements will allow comparisons with the upcoming NASA TSIS-2 mission. Antje Inness [European Centre for Medium-range Weather Forecasts (ECMWF)] described operational assimilation of OMI and TROPOMI near-real time data into the European Copernicus Atmosphere Monitoring Service (CAMS) daily analysis/forecast and re-analysis – see Figure 1.
In Memoriam: Johan de Vries
Johan de Vries
June 10, 1956 – May 8, 2024 Johan de Vries [Airbus Netherlands—Senior Specialist Remote Sensing] passed away suddenly on May 8, 2024, after a distinguished career. As a member of the Ozone Monitoring Instrument (OMI)–TROPOspheric Monitoring Instrument (TROPOMI) program, Johan conceptualized the idea of using a two-dimensional (2D) charged couple detector (CCD) for the OMI imaging spectrometer. This “push-broom” design led to high-spatial resolution spectra combined with high-spatial resolution and daily global coverage capability. His pioneering design for OMI has now been repeated on several other U.S. and international atmospheric composition measuring instruments – in both low and geostationary orbits – that are either in orbit or planned for launch soon. This achievement ensures that Johan’s legacy will live on for many years to come as these push-broom Earth observing spectrometers result in unprecedented data for environmental research and applications. The OMI and TROPOMI teams express their deepest condolences to de Vries family and colleagues over this loss.
Figure 1. An example of TROPOMI pixel nitrogen dioxide (NO2) observations over Europe on September 8, 2018 [top] and the corresponding super observations [bottom] for a model grid of 0.5 x 0.5o. Cloudy locations are colored grey. TROPOMI super observations are tested for use in the European Centre for Medium Range Weather Forecasting (ECMWF) Copernicus Atmosphere Monitoring Service (CAMS) data assimilation framework and will also be used for combined OMI–TROPOMI gridded datasets. Figure credit: reprinted from a 2024 paper posted on EGUSphere. Updates on OMI and TROPOMI Level-2 Data Products
The U.S. and Netherlands OMI STs continue to collaborate closely on reprocessing and improving OMI and TROPOMI L2 science products. During the meeting, one or more presenters reported on each product, which are described in the paragraphs that follow.
Serena Di Pede [KNMI] discussed the latest algorithm updates to the Collection 4 OMI Total Column Ozone (O3) product, which is derived using differential absorption spectroscopy (DOAS). She compared results from the new algorithm with the previous Collection 3 and with both the TROPOMI and OMI NASA O3 total column (Collection 3) algorithms. Collection 4 improved on previous versions by reducing the retrieval fit error and the along-track stripes of the product.
Juseon “Sunny” Bak and Xiong Liu [both from Smithsonian Astrophysical Observatory (SAO)] gave updates on the status of the Collection 4 O3 profile products.
Lok Lamsal [GSFC/University of Maryland, Baltimore County (UMBC)] and Henk Eskes [KNMI] compared Collection 3 and Collection 4 of the nitrogen dioxide (NO2) products.
Zolal Ayzpour [SAO] discussed the status of the OMI Collection 4 formaldehyde (HCHO) product.
Hyeong-Ahn Kwon [SAO] presented a poster that updated the Glyoxal product.
Omar Torres [GSFC] and Changwoo Ahn [GSFC/SSAI] presented regional trend analyses using the re-processed OMI Collection 4 absorbing aerosol product – see Figure 2.
Figure 2. Reprocessed OMI records (from Collection 4) of monthly average aerosol optical depth (AOD) at 388 nm derived from the OMI aerosol algorithm (OMAERUV) over Western North America (WNA): 30°N–50°N, 110°W–128°W) [top] and over Eastern China (EC): 25°N–43°N, 112°E–124°E) [bottom]. A repeatable annual cycle over WNA occurred with autumn minimum at around 0.1 and a spring maximum in the vicinity of 0.4 during the 2005–2016 period. After 2017 much larger AOD maxima in the late summer are associated with wildfire smoke occurrence. Over EC (bottom) the 2005–2014 AOD record depicts a large spring maxima (0.7 and larger) due to long-range transport of dust and secondary pollution aerosols followed by late autumn minima (around 0.3). A significant AOD decrease is observed starting in 2015 with reduced minimum and maximum values to about 0.2 and 0.5 respectively. The drastic change in AOD load over this region is associated with pollution control measures enacted over the last decade. Figure credit: Changwoo Ahn/GSFC/SSAI and Omar Torres/GSFC Updates on EOS Synergy Products
Several presenters and posters during the meeting gave updates on EOS synergy products, where OMI data are combined with data from another instrument on one of the EOS flagships. These are described below.
Brad Fisher [SSAI] presented a poster on the Joint OMI–Moderate Resolution Imaging Spectroradiometer (MODIS) cloud products.
Wenhan Qin [GSFC/SSAI] presented a poster on the MODIS–OMI Geometry Dependent Lambertian Equivalent Surface Reflectivity (GLER) product.
Jerry Ziemke [GSFC and Morgan State University (MSU)] presented on the OMI–MLS Tropospheric Ozone product that showed post-COVID tropospheric O3 levels measured using this product, which are consistent with similar measurements obtained using other satellite O3 data – see Figure 3.
Figure 3. Anomaly maps of merged tropospheric column O3 (TCO) satellite data (Dobson Units) for spring–summer 2020–2023. In this context, an anomaly is defined as deseasonalized O3 data. The anomaly maps are derived by first calculating seasonal climatology maps for 2016–2019 (i.e., pre-COVID pandemic) and then subtracting these climatology maps from the entire data record.
Note: The sensors used in this analysis include: the Ozone Mapping and Profiler Suite (OMPS)/ Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) and Cross-track Infrared Sounder (CrIS) on the Joint Polar Satellite System (JPSS) missions, which currently include the joint NASA–NOAA Suomi National Polar-orbiting Partnership (Suomi NPP), NOAA-20, and NOAA-21; the Earth Polychromatic Imaging Camera (EPIC)/MERRA-2 on the Deep Space Climate Observatory (DSCOVR); the Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS), both on EOS Aura; the Infrared Atmospheric Sounding Interferometer (IASI)/ Fast Optimal Retrievals on Layers (FORLI), IASI/SOftware for Fast Retrievals of IASI Data (SOFRID), and IASI/Global Ozone Monitoring Experiment–2 (GOME2). IASI flies on the European MetOp-A, -B, and -C missions. The OMPS/MERRA-2 and EPIC/MERRA-2 products subtract coincident MERRA-2 stratospheric column O3 from total O3 to derive tropospheric column O3. Figure credit: Jerry Ziemke/GSFC and Morgan State University (MSU) Updates on Multisatellite Climate Data Records
The OMI ST also discussed refining and analyzing multisatellite climate data records (CDRs) that have been processed with consistent algorithms. Several presenters reported on this work, who are mentioned below.
Jenny Stavrakou [Koninklijk Belgisch Instituut voor Ruimte-Aeronomie, Royal Belgian Institute for Space Aeronomy (BIRA–IASB)], reported on work focusing on the OMI and TROPOMI HCHO CDR and Huan Yu [BIRA–IASB)] reported harmonized OMI and TROPOMI cloud height datasets based on improved O2-O2 absorption retrieval algorithm.
Lok Lamsal [GSFC/UMBC, Goddard Earth Sciences Technology and Research (GESTAR) II], Henk Eskes, and Pepijn Veefkind [KNMI] reported on the OMI and TROPOMI NO2 CDRs – see Figure 4.
Si-Wan Kim [Yonsei University, South Korea] reported on OMI and TROPOMI long-term NO2 trends.
Figure 4. OMI nitrogen dioxide (NO2) time series bridging the first GOME mission (which flew on the European Remote Sensing Satellite–2 (ERS–2) from 1995–2011 with limited coverage after 2003) and measurements from the two currently operating missions – OMI (2004–present) and TROPOMI (2017–present) – offer consistent climate data records that allow for studying long-term changes. This example shows tropospheric NO2 column time series from three instruments over Phoenix, AZ. The overlap between the OMI and TROPOMI missions allows for intercomparison between the two, which is crucial to avoid continuity-gaps in multi-instrument time series. The ERS-2 (GOME) had a morning equator crossing time (10:30 AM), while Aura (OMI) and Metop (TROPOMI) have afternoon equator crossing times of 1:45 PM and 1:30 PM respectively. Figure credit: Lok Lamsal/GSFC/University of Maryland, Baltimore County (UMBC) Update on Aura’s Drifting Orbit
Bryan Duncan [GSFC—Aura Project Scientist] closed out the first day with a presentation summarizing predictions of Aura’s drifting orbit. Overall, the impact of Aura’s drift is expected to be minor, and the OMI and MLS teams will be able to maintain science quality data for most data products. He thanked the OMI/TROPOMI ST and user community for expressing their strong support for continuing Aura observations until the end of the Aura mission in mid–2026.
DAY TWO
The second day of the meeting focused on current and upcoming LEO and GEO Atmospheric Composition (AC) missions.
TROPOMI Mission and Data Product Updates
Veefkind presented an update on the TROPOMI mission, which provides continuation and enhancements for all OMI products. Tobias Borssdorf [Stichting Ruimte Onderzoek Nederland (SRON), or Netherlands Institute for Space Research] explained how TROPOMI, with its innovative shortwave infrared (SWIR) spectrometer, measures CH4 and carbon monoxide (CO). This approach continues measurements that began by the Measurements of Pollution in the Troposphere (MOPITT) instrument on Terra.
Hiren Jethva [NASA Airborne Science Program] and Torres presented new TROPOMI near-UV aerosol products, including a new aerosol layer optical centroid height product, which takes advantage of the TROPOMI extended spectral range – see Figure 5.
Figure 5. Global gridded (0.10° x 0.10°) composite map of aerosol layer optical centroid height (AH) retrieved from TROPOMI O2-B band observations from May–September 2023. Figure credit: Hiren Jethva/NASA Airborne Science Program GEMS–TEMPO–Sentinel-4 (UVN): A Geostationary Air Quality Constellation
TROPOMI global observations serve as a de facto calibration standard used to homogenize a new constellation of three missions that will provide AC observations for most of the Northern Hemisphere from GEO. Two of the three constellation members are already in orbit. Jhoon Kim [Yonsei University—PI] discussed the Geostationary Environmental Monitoring Spectrometer (GEMS), launched on February 19, 2020 aboard the Republic of Korea’s GEO-KOMPSAT-2B satellite. It is making GEO AC measurements over Asia. The GEMS team is working on validating measurements of NO2 diurnal variations using ground-based measurements from the PANDORA Global Network over Asia and aircraft measurements from the ASIA–AQ field campaign.
Liu discussed NASA’s Tropospheric Emission Monitoring of Pollution (TEMPO) spectrometer, launched on April 7, 2023, aboard a commercial INTELSAT 40E satellite. From its GEO vantage point, TEMPO can observe the Continental U.S., Southern Canada, Mexico, and the coastal waters of the Northwestern Atlantic and Northeastern Pacific oceans.
Gonzales Abad [SAO] presented the first measurements from TEMPO. He explained that TEMPO’s design is similar to GEMS, but GEMS includes an additional visible and near infrared (VNIR) spectral channel (540–740 nm) to measure tropospheric O3, O2, and water vapor (H2Ov). TEMPO can perform optimized morning scans, twilight scans, and scans with high temporal resolution (5–10 minutes) over selected regions. Abad reported that the TEMPO team released L1B spectra and the first provisional public L2 products (Version 3), including NO2, HCHO, and total column O3. Andrew Rollins [National Oceanic and Atmospheric Administration’s (NOAA) Chemical Sciences Laboratory (CSL)] reported that the TEMPO team is working on validation of provisional data using both ground-based data from PANDORA spectrometers and data collected during several different airborne campaigns completed during the summer of 2023 and compiled on the AGES+ website.
Ben Veihelmann [ESA’s European Space Research and Technology Center—PI] explained that ESA’s Copernicus Sentinel-4 mission will be the final member of the GEO AC constellation. Veefkind summarized the Sentinel-4 mission, which is expected to launch on the Meteosat Third Generation (MTG)-Sounder 1 (MTG-S1) platform in 2025. The mission is dedicated to measuring air quality and O3 over Europe and parts of the Atlantic and North Africa. Sentinel-4 will deploy the first operational UV-Vis-NIR (UVN) imaging spectrometer on a geostationary satellite. (Airbus will build UVN, with ESA providing guidance.) Sentinel-4 includes two instruments launched in sequence on MTG-S1 and MTG-S2 platforms designed to have a combined lifetime of 15 years. The mission by the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) will operate Sentinel-4, and the Deutsches Zentrum für Luft- und Raumfahrt (DLR) or German Aerospace Center will be responsible for operational L2 processing.
These three GEO AC missions, along with the upcoming ESA/EUMETSAT/Copernicus LEO (morning orbit, 9:30 a.m.) Sentinel-5 (S5) mission, will complete a LEO–GEO satellite constellation that will enable monitoring of the most industrialized and polluted regions in the Northern Hemisphere into the 2030s. Sentinel-5 will not continue the OMI–TROPOMI data record in the early afternoon; however, it will be placed in the morning orbit and follow ESA’s Global Ozone Monitoring Experiment (GOME) and EUMETSAT GOME-2 missions. By contrast, GEO AC observations over the Southern Hemisphere are currently not available. Several presenters described ongoing projects for capacity building for LEO satellite air quality data uptake and emission monitoring in Africa and advocated for the new geostationary measurements.
Synergy with Other Current or Upcoming Missions
Attendees discussed the synergy between upcoming AC, GHG, and ocean color missions. Current trends in satellite AC measurements are toward increased spatial resolution and combined observations of short-lived reactive trace gases – which are important for air quality (AQ) monitoring – and long-lived GHG – which are important for climate monitoring and carbon cycle assessments. Some trace gases (e.g., O3 and CH4) are both polluters and GHG agents. Others [e.g., NO2 and sulfur dioxide (SO2 )] are aerosol [particulate matter (PM)] and O3 precursors and are used as proxies and spatial indicators for anthropogenic CO2 and CH4 emissions.
Yasjka Meijer [ESA—Copernicus Anthropogenic Carbon Dioxide Monitoring (CO2M) Mission Scientist]) reviewed the plans for CO2M, which includes high-resolution measurements [~4 km2 (~1.5 mi2)] of CO2 , CH4 , and NO2.
Jochen Landgraf [SRON] described ESA’s new Twin Anthropogenic Greenhouse Gas Observers (TANGO) mission, which has the objective to measure CO2 , CH4 , and NO2 at even higher spatial resolution [~300 m (~984 ft)] using two small CubeSat spectrometers flying in formation.
Hiroshi Tanimoto [National Institute for Environmental Studies, Japan] described the Japan Aerospace Exploration Agency’s (JAXA) Global Observing SATellite for greenhouse gases and water cycle (GOSAT-GW) mission, which includes the Total Anthropogenic and Natural Emission mapping SpectrOmeter (TANSO-3) spectrometer to simultaneously measure CO2 , CH4, and NO2 with ~1–3 km (~0.6–1.8 mi) spatial resolution in focus mode. GOSAT-GW will also fly the Advanced Microwave Scanning Radiometer 3 (AMSR3).
Joanna Joiner [GSFC—Geostationary Extended Operations (GeoXO) Project Scientist and ACX Instrument Scientist] described the plans for the next-generation U.S. geosynchronous satellite constellation, which will consist of three satellites covering the full Earth disk: GEO-East, GEO-West, and GEO-Central. (By contrast, the current Geostationary Operational Environmental Satellite (GOES) series has two satellites: GOES–East and GOES–West.) GEO-Central will carry an advanced infrared sounder (GXS) for measuring vertical profiles of many trace gases, temperature and humidity, and a new UV-VIS spectrometer (ACX), which is a follow-on to TEMPO for AQ applications. Both GXS and ACX instruments will be built by BAE Systems, which acquired Ball Aerospace and Technology, and will also build the GeoXO ocean color spectrometer (OCX).
Andrew Sayer [UMBC] described NASA’s Plankton, Aerosols, Clouds, and ocean Ecosystem (PACE), which launched on February 8, 2024. The PACE payload includes a high-spatial resolution [~1 km (~0.6 mi) at nadir] Ocean Color Instrument (OCI), which is a UV-Vis-NIR spectrometer with discrete SWIR bands presenting additional opportunities for synergistic observations with the AC constellation. Sayer presented OCI “first light” aerosol data processed using the unified retrieval algorithm developed by Lorraine Remer [UMBC].
The second day concluded with a joint crossover session with NASA’s Health and Air Quality Applied Sciences Team (HAQAST) followed by a poster session. Several OMI–TROPOMI STM participants presented on a variety of topics that illustrate how OMI and TROPOMI data are being used to support numerous health and AQ applications. Duncan, who is also a member of HAQAST team, presented “20 years of health and air quality applications enabled by OMI data.” He highlighted OMI contributions to AQ and health applications, including NO2 trend monitoring, inferring trends of co-emitted species [e.g., CO2, CO, some Volatile Organic Compounds (VOCs)], validation of new satellite missions (e.g., TEMPO, PACE), and burden of disease studies.
DAY THREE
Discussions on the third day focused on advanced retrieval algorithms, leading to new products and new applications for OMI and TROPOMI data. Several presentations described applications of TROPOMI CH4 data and synergy with small satellites.
Advanced Retrieval Algorithms and New Data Products
Ilse Aben [SRON] described TROPOMI global detection of CH4 super-emitters using an automated system based on Machine Learning (ML) techniques – see Figure 6. Berend Schuit [SRON] provided additional detail on these methods. He introduced the TROPOMI CH4 web site to the meeting participants. He explained how TROPOMI global CH4 measurements use “tip-and-cue” dedicated satellites with much higher spatial resolution instruments [e.g., GHGSat with ~25-m (~82-ft) resolution] to scan for individual sources and estimate emission rates. Most CH4 super-emitters are related to urban areas and/or landfills, followed by plumes from gas and oil industries and coal mines.
Figure 6. Methane plume map produced by SRON shows TROPOMI large CH4 emission plumes for the week of the OMI–TROPOMI meeting (June 3–6, 2024). Figure credit: Itse Aben/Stichting Ruimte Onderzoek Nederland (SRON) Alba Lorente [Environmental Defense Fund—Methane Scientist] introduced a new MethaneSAT satellite launched in March 2024, which aims to fill the gap in understanding CH4 emissions on a regional scale [200 x 200 km2 (~77 x 77 mi2)] from at least 80% of global oil and gas production, agriculture, and urban regions. Alex Bradley [University of Colorado, Boulder] described improvements to TROPOMI CH4 retrievals that were achieved by correcting seasonal effects of changing surface albedo.
Daniel Jacob [Harvard University] presented several topics, including the highest resolution [~30 m (~98 ft)] NO2 plume retrievals from Landsat-8 – see Figure 7 – and Sentinel-2 imagers. He also discussed using a ML technique trained with TROPOMI data to improve NO2 retrievals from GEMS and modeling NO2 diurnal cycle and emission estimates. He introduced the ratio of ammonia (NH3) to NO2 (NH3/NO2) as an indicator of particulate matter with diameters less than 2.5 µm (PM2.5) nitrate sensitivity regime. Jacob emphasized the challenges related to satellite NO2 retrievals (e.g., accounting for a free-tropospheric NO2 background and aerosols).
Figure 7. Landsat Optical Land Imager (OLI) image, obtained on October 17, 2021 over Saudi Arabia, shows power plant exhaust, which contains nitrogen dioxide (NO2) drifting downwind from the sources (the two green circles are the stacks). The ultra-blue channel (430–450 nm) on OLI enables quantitative detection of NO2 in plumes from large point sources at 30-m (~98-ft) resolution. This provides a unique ability for monitoring point-source emissions of oxides of nitrogen (NOx). The two stacks in the image are separated by 2 km (~1.2 mi). Figure credit: Daniel Jacob – repurposed from a 2024 publication in Proceedings of the National Academies of Sciences (PNAS) Steffen Beirle [Max Planck Institute for Chemistry, Germany] explained his work to fit TROPOMI NO2 column measurements to investigate nitric oxide (NO) to NO2 processing in power plant plumes. Debra Griffin [Environment and Climate Change Canada (ECCC)] used TROPOMI NO2 observations and ML random forest technique to estimate NO2 surface concentrations. Sara Martinez-Alonso [NCAR] investigated geographical and seasonal variations in NO2 diurnal cycle using GEMS and TEMPO data. Ziemkecombined satellite O3 data to confirm a persistent low anomaly (~5–15%) in tropospheric O3 after 2020. Jethva presented advanced OMI and TROPOMI absorbing aerosol products. Yu described improved OMI and TROPOMI cloud datasets using the O2-O2 absorption band at 477 nm. Nicholas Parazoo [Jet Propulsion Laboratory (JPL)] described TROPOMI Fraunhofer line retrievals of red solar-induced chlorophyll fluorescence (SIF) near O2-B band (663–685 nm) to improve mapping of ocean primary productivity. Liyin He [Duke University] described using satellite terrestrial SIF data to study the effect of particulate pollution on ecosystem productivity.
New Applications
Zachary Fasnacht [SSAI] used OMI and TROPOMI spectra to train a neural network to gap-fill MODIS and Visible Infrared Imaging Radiometer Suite (VIIRS) ocean color data under aerosol, sun glint, and partly cloudy conditions. This ML method can also be applied to PACE OCI spectra. Anu-Maija Sundström [Finnish Meteorological Institute (FMI)] used OMI and TROPOMI SO2 and O3 data as proxies to study new particle formation events. Lindsey Anderson [University of Colorado, Boulder] described how she used TROPOMI NO2 and CO measurements to estimate the composition of wildfire emissions and their effect on forecasted air quality. Heesung Chong [SAO] applied OMI bromine oxide (BrO) retrievals to the NOAA operational Ozone Mapping and Profiling Suite Nadir Mapper (OMPS-NM) on joint NOAA–NASA Suomi-National Polar-orbiting Partnership (Suomi NPP) satellite with the possibility to continue afternoon measurements using similar OMPS-NM instruments on the four Joint Polar Satellite System missions (JPSS-1,-2,-3,-4) into the 2030s. (JPSS-1 and -2 are now in orbit and known as NOAA-20 and -21 respectively; JPSS-4 is planned for launch in 2027, with JPSS-3 currently targeted for 2032.)
Kim demonstrated the potential for using satellite NO2 and SO2 emissions as a window into socioeconomic issues that are not apparent by other methods. For example, she showed how OMI and TROPOMI data were widely used to monitor air quality improvements in the aftermath of COVID-19 lockdowns. (Brad Fisher [SSAI] presented a poster on a similar topic.)
Cathy Clerbaux [Center National d’Études Spatiale (CNES), or French Space Agency] showed how her team used TROPOMI NO2 data to trace the signal emitted by ships and used this information to determine how the shipping lanes through the Suez Canal changed in response to unrest in the Middle East. Iolanda Ialongo [FMI] showed a similar drop of NO2 emissions over Donetsk region due to the war in Ukraine. Levelt showed how OMI and TROPOMI NO2 data are used for capacity-building projects and for air quality reporting in Africa. She also advocated for additional geostationary AQ measurements over Africa.
DAY FOUR
Discussions on the final day focused on various methods of assimilating satellite data into air quality models for emission inversions and aircraft TEMPO validation campaigns. The meeting ended with Levelt giving her unique perspective on the OMI mission, as she reflected on more than two decades being involved with the development, launch, operation, and maintenance of OMI.
Assimilating Satellite Data into Models for Emissions
Brian McDonald [CSL] described advance chemical data assimilation of satellite data for emission inversions and the GReenhouse gas And Air Pollutants Emissions System (GRA2PES). He showed examples of assimilations using TROPOMI and TEMPO NO2 observations to adjust a priori emissions. He also showed that when TEMPO data are assimilated, NOx emissions adjust faster and tend to perform better at the urban scale. Adrian Jost [Max Planck Institute for Chemistry] described the ESA-funded World Emission project to improve pollutant and GHG emission inventories using satellite data. He showed examples of TROPOMI SO2 emissions from large-point sources and compared the data with bottom-up and NASA SO2 emissions catalogue.
Ivar van der Velde [SRON] presented a method to evaluate fire emissions using new satellite imagery of burned area and TROPOMI CO. Helene Peiro [SRON] described her work to combine TROPOMI CO and burned area information to compare the impact of prescribed fires versus wildfires on air quality in the U.S. She concluded that prescribed burning reduces CO pollution. Barbara Dix [University of Colorado, Boulder, Cooperative Institute for Research in Environmental Sciences] derived NOx emissions from U.S. oil and natural gas production using TROPOMI NO2 data and flux divergence method. She estimated TROPOMI CH4 emissions from Denver–Julesburg oil and natural gas production. Dix explained that the remaining challenge is to separate oil and gas emissions from other co-located CH4 sources. Ben Gaubert [NCAR, Atmospheric Chemistry Observations and Modeling] described nonlinear and non-Gaussian ensemble assimilation of MOPITT CO using the data assimilation research testbed (DART).
Andrew (Drew) Rollings [CSL] presented first TEMPO validation results from airborne field campaigns in 2023 (AGES+ ), including NOAA CSL Atmospheric Emissions and Reactions observed from Megacities to Marine Aeras (AEROMMA) and NASA’s Synergistic TEMPO Air Quality Science (STAQS) campaigns.
A Reflection on Twenty Years of OMI Observations
Levelt gave a closing presentation in which she reflected on her first involvement with the OMI mission as a young scientist back in 1998. This led to a collaboration with the international ST to develop the instrument, which was included as part of Aura’s payload when it launched in July 2004. She reminisced about important highlights from 2 decades of OMI, e.g., the 10-year anniversary STM at KNMI in 2014 (see “Celebrating Ten Years of OMI Observations,” The Earth Observer, May–Jun 2014, 26:3, 23–30), and the OMI ST receiving the NASA/U.S. Geological Survey Pecora award in 2018 and the American Meteorological Society’s Special award in 2021.
Levelt pointed out that in this combined OMI–TROPOMI meeting the movement towards using air pollution and GHG data together became apparent. She ended by saying that the OMI instrument continues to “age gracefully” and its legacy continues with the TROPOMI and LEO–GEO atmospheric composition constellation of satellites that were discussed during the meeting.
Conclusion
Overall, the second OMI–TROPOMI STM acknowledged OMI’s pioneering role and TROPOMI’s unique enhancements in measurements of atmospheric composition:
Ozone Layer Monitoring: Over the past two decades, OMI has provided invaluable data on the concentration and distribution of O3 in the Earth’s stratosphere. This data has been crucial for understanding and monitoring the recovery of the O3 layer following international agreements, such as the Montreal Protocol. Air Quality Assessment: OMI’s high-resolution measurements of air pollutants, such as NO2, SO2, and HCHO, have significantly advanced our understanding of air quality. This information has been vital for tracking pollution sources, studying their transport and transformation, and assessing their impact on human health and the environment. Climate Research: The data collected by OMI has enhanced our knowledge of the interactions between atmospheric chemistry and climate change. These insights have been instrumental in refining climate models and improving our predictions of future climate scenarios. Global Impact: The OMI instrument has provided near-daily global coverage of atmospheric data, which has been essential for scientists and policymakers worldwide. The comprehensive and reliable data from OMI has supported countless research projects and informed decisions aimed at protecting and improving our environment. OMI remains one of the most stable UV/Vis instruments over its two decades of science and trend quality data collection. The success of the OMI and TROPOMI instruments is a testament to the collaboration, expertise, and dedication of both teams.
Nickolay Krotkov
NASA’s Goddard Space Flight Center
Nickolay.a.krotkov@nasa.gov
Pieternel Levelt
National Center for Atmospheric Research, Atmospheric Chemistry Observations & Modeling
levelt@ucar.edu
Share
Details
Last Updated Nov 12, 2024 Related Terms
Earth Science View the full article
-
By NASA
Researchers demonstrated the feasibility of 3D bioprinting a meniscus or knee cartilage tissue in microgravity. This successful result advances technology for bioprinting tissue to treat musculoskeletal injuries on long-term spaceflight or in extraterrestrial settings where resources and supply capacities are limited.
BFF Meniscus-2 evaluated using the BioFabrication Facility to 3D print knee cartilage tissue using bioinks and cells. The meniscus is the first engineered tissue of an anatomically relevant shape printed on the station. Manufactured human tissues have potential as alternatives to donor organs, which are in short supply. Bioprinting in microgravity overcomes some of the challenges present in Earth’s gravity, such as deformation or collapse of tissue structures.
A human knee meniscus 3D bioprinted in space using the International Space Station’s BioFabrication Facility.Redwire Complex cultures of central nervous system cells known as brain organoids can be maintained in microgravity for long periods of time and show faster development of neurons than cultures on Earth. These findings could help researchers develop treatments for neurodegenerative diseases on Earth and address potential adverse neurological effects of spaceflight.
Cosmic Brain Organoids examined growth and gene expression in 3D organoids created with neural stem cells from individuals with primary progressive multiple sclerosis and Parkinson’s disease. Results could improve understanding of these neurological diseases and support development of new treatments. Researchers plan additional studies on the underlying causes of the accelerated neuron maturation.
Neural growth in brain organoids that spent more than a month in space. Jeanne Frances Loring, National Stem Cell Foundation Researchers demonstrated that induced pluripotent stem cells (iPSCs) can be processed in microgravity using off the-shelf cell culture materials. Using standard laboratory equipment and protocols could reduce costs and make space-based biomedical research accessible to a broader range of scientists and institutions.
Stellar Stem Cells Ax-2 evaluated how microgravity affects methods used to generate and grow stem cells into a variety of tissue types on the ground. iPSCs can give rise to any type of cell or tissue in the human body, and insight into processing in space could support their use in regenerative medicine and future large-scale biomanufacturing of cellular therapeutics in space.
NASA astronaut Peggy Whitson, an Axiom Mission 2 crew member, works on stem cell research on a previous mission. NASA/Shane KimbroughView the full article
-
By NASA
4 Min Read Student-Built Capsules Endure Heat of Re-entry for NASA Science
The five capsules of the KREPE-2 mission are pictured on Earth prior to flight. Credits: University of Kentucky. In July 2024, five student-built capsules endured the scorching heat of re-entry through Earth’s atmosphere as part of the second Kentucky Re-Entry Probe Experiment (KREPE-2). Scientists are now analyzing the data from the KREPE-2 experiments, which could advance the development of heat shields that protect spacecraft when they return to Earth.
The mission was designed to put a variety of heat shield prototypes to the test in authentic re-entry conditions to see how they would perform. These experimental capsules, which were built by students at the University of Kentucky and funded by the NASA Established Program to Stimulate Competitive Research (EPSCoR) within NASA’s Office of STEM Engagement, all survived more than 4,000 degrees Fahrenheit during descent.
The football-sized capsules also successfully transmitted valuable data via the Iridium satellite network along their fiery journey. The trove of information they provided is currently being analyzed to consider in current and future spacecraft design, and to improve upon designs for future experiments.
“These data – and the instruments used to obtain the data – assist NASA with designing and assessing the performance of current and new spacecraft that transport crew and cargo to and from space,” said Stan Bouslog, thermal protection system senior discipline expert at NASA’s Johnson Space Center in Houston who served as the agency’s technical monitor for the project.
Taking the Plunge: Communicating Through a Fiery Descent
“The only way to ‘test like you fly’ a thermal protection system is to expose it to actual hypersonic flight through an atmosphere,” Bouslog said.
The self-contained capsules launched aboard an uncrewed Northrop Grumman Cygnus spacecraft in January 2024 along with other cargo bound for the International Space Station. The cargo craft detached from the space station July 12 as the orbiting laboratory flew above the south Atlantic Ocean. As the Cygnus spacecraft began its planned breakup during re-entry, the KREPE-2 capsules detected a signal – a temperature spike or acceleration – to start recording data and were released from the vehicle. At that point, they were traveling at a velocity of about 16,000 miles per hour at an altitude of approximately 180,000 feet.
The University of Kentucky student team and advisors watched and waited to learn how the capsules had fared.
As the capsules descended through the atmosphere, one group watched from aboard an aircraft flying near the Cook Islands in the south Pacific Ocean, where they tracked the return of the Cygnus spacecraft. The flight was arranged in partnership with the University of Southern Queensland in Toowoomba, Queensland, Australia, and the University of Stuttgart in Stuttgart, Germany. Alexandre Martin, professor of mechanical and aerospace engineering at the University of Kentucky and the principal investigator for the experiment, was on that flight.
“We flew in close to the re-entry path to take scientific measurements,” Martin said, adding that they used multiple cameras and spectrometers to observe re-entry. “We now have a much better understanding of the break-up event of the Cygnus vehicle, and thus the release of the capsules.”
Meanwhile, members of the University of Kentucky’s Hypersonic Institute had gathered at the university to watch as KREPE-2 data arrived via email. All five successfully communicated their flight conditions as they hurtled to Earth.
“It will take time to extract the data and analyze it,” Martin said. “But the big accomplishment was that every capsule sent data.”
Members of the University of Kentucky student team have begun analyzing the data to digitally reconstruct the flight environment at the time of transmission, providing key insights for future computer modeling and heat shield design.
An artist’s rendering of one of the KREPE-2 capsules during re-entry. A. Martin, P. Rodgers, L. Young, J. Adams, University of Kentucky Building on Student Success
The mission builds on the accomplishments of KREPE-1, which took place in December 2022. In that experiment, two capsules recorded temperature measurements as they re-entered Earth’s atmosphere and relayed that data to the ground.
The extensive dataset collected during the KREPE-2 re-entry includes heat shield measurements, such as temperature, as well as flight data including pressure, acceleration, and angular velocity. The team also successfully tested a spectrometer that provided spectral data of the shockwave in front of a capsule.
“KREPE-1 was really to show we could do it,” Martin said. “For KREPE-2, we wanted to fully instrument the capsules and really see what we could learn.”
KREPE-3 is currently set to take place in 2026.
The ongoing project has provided valuable opportunities for the University of Kentucky student team, from undergrads to PhD students, to contribute to spaceflight technology innovation.
“This effort is done by students entirely: fabrication, running simulations, handling all the NASA reviews, and doing all the testing,” Martin said. “We’re there supervising, of course, but it’s always the students who make these missions possible.”
Related links:
EPSCoR Space Station Research Explorer: Kentucky Re-entry Probe Experiment-2 Science Launches to Space Station on NASA’s 20th Northrop Grumman Mission Big Goals, Small Package: Enabling Compact Deliveries from Space Keep Exploring Discover More STEM Topics From NASA
For Colleges and Universities
Established Program to Stimulate Competitive Research
About STEM Engagement at NASA
Learning Resources
View the full article
-
-
Check out these Videos
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.