Members Can Post Anonymously On This Site
-
Similar Topics
-
By NASA
Explore This Section Earth Earth Observer Editor’s Corner Feature Articles Meeting Summaries News Science in the News Calendars In Memoriam Announcements More Archives Conference Schedules Style Guide 31 min read
Summary of the 2025 GEDI Science Team Meeting
Introduction
The 2025 Global Ecosystem Dynamics Investigation (GEDI) Science Team Meeting (STM) took place April 1–3, 2025 at the University of Maryland, College Park (UMD). Upwards of 60 participants attended in-person, while several others joined virtually by Zoom. The GEDI Mission and Competed Science Team members were in attendance along with the GEDI NASA program manager and various postdoctoral associates, graduate students, collaborators, and data users – see Photo. Participants shared updates on the GEDI instrument and data products post-hibernation with the GEDI community. They also shared progress reports on the second Competed Science Team cohort’s projects as well as applications of GEDI data.
This article provides a mission status update and summaries of the presentations given at the STM. Readers who would like to learn more about certain topics can submit specific questions through the GEDI website’s contact form.
Photo. Attendees, both in person and virtual, at the 2025 GEDI Science Team meeting. Photo credit: Talia Schwelling Mission Status Update: GEDI Up and Running After its Time in Hibernation
When the 2023 GEDI STM summary was published in June 2024 – see archived article, “Summary of the 2023 GEDI Science Team Meeting” [The Earth Observer, June 18, 2024] – GEDI had been placed in a temporary state of hibernation and moved from the International Space Station’s (ISS) Japanese Experiment Module–Exposed Facility (JEM–EF) Exposed Facility Unit (EFU)-6 to EFU-7 (storage).
Two years later, as the 2025 GEDI STM took place, the GEDI instrument was back in its original location on EFU-6 collecting high-resolution observations of Earth’s three-dimensional (3D) structure from space.
DAY ONE
GEDI Mission and Data Product Status I
Ralph Dubayah [UMD—GEDI Principal Investigator (PI)] opened the STM with updates on mission status (see previous section) and the development of current and pending GEDI data products.
Following its hibernation on the ISS from March 2023–April 2024, the GEDI mission entered its second extension period. Since re-installation, the instrument’s lasers have been operating nominally, steadily collecting data, increasing coverage, and filling gaps. As of November 27, 2024, GEDI had collected 33 billion Level-2A (L2A) land surface returns, with approximately 12.1 billion passing quality filters. Since the last STM, an additional 1422 new simulated GEDI footprints have been added to GEDI’s forest structure and biomass database (FSBD), which is a database of forest inventory and airborne laser scanning data (ALS) from around the globe that is used for cal/val of GEDI data. The FSBD now has 27,876 simulated footprints in total – see Figure 1. This data will support improved L4A biomass algorithm calibration.
Figure 1. Training samples, or simulated footprints, are derived from coincident forest inventory and ALS data. DBT = deciduous broadleaf, EBT = evergreen broadleaf, ENT = evergreen needleleaf, GSW = grass, shrub, woodland. Figure credit: David Minor Version 2.1 (V2.1) of GEDI L1B, L2A, L2B, and L4A data products are the latest product releases available for download. This version incorporates post-storage data through November 2024. In January 2025, the team also released the new L4C footprint-level Waveform Structural Complexity Index (WSCI) product using pre-storage data. The upcoming V3.0 release will incorporate pre- and post-storage data that will improve quality filtering, geolocation accuracy, and algorithm performance.
Although GEDI met its L1 mission science requirements before entering hibernation, orbital resonance on the ISS impacted GEDI’s coverage in the tropics. To help address these gaps, the team is exploring data fusion opportunities with other missions – e.g., NASA-Indian Space Research Organisation Synthetic Aperture Radar (NISAR), the Deutsches Zentrum für Luft- und Raumfahrt’s (DLR – German Aerospace Center) Terra Synthetic Aperture Radar–X (TerraSAR-X) and TerraSAR add-on for Digital Elevation Measurement (TanDEM-X) missions, and the European Space Agency’s upcoming forest mission – Biomass. [UPDATE: Biomass launched successfully on April 29, 2025 from Europe’s Spaceport in Korou, French Guiana, and NISAR launched July 30, 2025 from the Satish Dhawan Space Centre located on Sriharikota Island in India.] Additional ongoing mission team efforts include advancing waveform processing, developing gridded products tailored to end-user needs, understanding error and bias, and continuing expansion of the FSBD.
Dubayah concluded by highlighting the steady rise in GEDI-related publications and datasets appearing in high-impact journals, including PNAS, Nature, and Science families. Visit the GEDI website to gain access to a comprehensive list of GEDI-related publications.
After hearing general updates from the mission PI, attendees heard more in-depth reports on science data planning, mission operations, and instrument status.
Scott Luthcke [NASA’s Goddard Space Flight Center (GSFC)—GEDI Co-Investigator (Co-I)] reported on Science Operations Center activities, including geolocation performance and improvements. He shared that the Science Planning System, which is used to plan GEDI data acquisition locations, has been upgraded to improve targeting capabilities using high-resolution Reference Ground Tracks. The Science Data Processing System also underwent a technical refresh that increased computational and storage capability and has completed processing and delivery of all V2.1 data products, including post-storage data (April–November 2024), to the Land Processes and Oak Ridge National Laboratory (ORNL) Distributed Active Archive Centers (DAACs).
Luthcke explained that V2.1 improves on precision orbit determination, precision attitude determination, tracking point modeling, time tags, and oscillator calibration. Looking ahead, V3.0 will enhance range bias calibration, improved pointing bias calibration, and modifications to L1A, L1B, L2A, and L2B products. Luthcke also discussed updates to the L3 data product, which include corrected timing and range bias, improved positioning and elevation, and a wall-to-wall 1-km (0.62-mi) elevation map to be released alongside V3.0.
Tony Scaffardi [GSFC—GEDI Mission Director] provided an update on the Science and Mission Operations Center since its post-hibernation return to science operations on June 3, 2024. He addressed various on-orbit events that may have briefly disrupted data collection and reviewed upcoming ISS altitude plans. As of March 2025, each of the instrument’s three lasers logged over 22,000 hours in firing mode, collecting more than 20 billion shots each, with 72% of that time directly over land surfaces. As of April 2025, 95,346 hours of science data have been downlinked, averaging 51.21 GB of data per day.
Bryan Blair [GSFC—Deputy PI and Instrument Scientist] concluded this section of the meeting with a discussion of GEDI instrument status, reporting that all three lasers are operating nominally and that both the detectors and digitizers continue to perform well. He noted that the laser pulse shapes have remained stable since the mission began, indicating consistent system performance over time. Blair also addressed the inherent challenges of operating in space, such as radiation exposure, and emphasized the importance of designing systems for graceful degradation. A recent firmware update was successfully applied to all three digitizers, and no life-limiting concerns have been identified to date.
Competed Science Team Presentations – Session I
Jim Kellner [Brown University—GEDI Co-I] kicked off the Competed Science Team (CST) presentations with an overview of his work investigating the role of stratification and quality filtering to improve GEDI data products and the impact of stratification error on prediction. He explained how GEDI quality filtering and aboveground biomass density (AGBD) model selection and prediction rely heavily on stratification by plant functional type (PFT) and geographic world region. Thus, evaluation and improvement of stratification and quality filtering will help maximize the number of usable GEDI shots, some of which are potentially excluded unnecessarily. To support these improvements, Kellner is exploring replacement of the current 1-km (0.62-mi) stratification layer with a 30-m (98-ft) product derived from Landsat and similarly upgrading the 500-m (1640-ft) phenology stratification layer to a 30-m (98-ft) Landsat version. These changes aim to improve the L4A footprint-level AGBD estimates in particular, but flow through to the GEDI L4B data product.
Birgit Peterson [United States Geological Survey (USGS), Earth Resources Observation and Science (EROS) Center] presented her research on the decomposition of GEDI waveforms to derive vegetation structure information for 3D fuels and wildfire modeling, emphasizing the importance of consistent and comprehensive information on vegetation status for effective wildland fire management. Canopy structure data, like that provided by GEDI, can play a key role in developing physics-based fire behavior models, such as QUIC-Fire. With study sites in South Dakota, the Sierra Nevada, and dispersed around the southeastern United States, Peterson’s work aims to demonstrate how vegetation structure parameters needed to run the QUIC-Fire model can be derived from GEDI waveform data.
David Roy [Michigan State University] shared updates on his CST project leveraging GEDI data to improve understanding of species-specific tropical forest regrowth in central Africa. Focusing on the Mai Ndombe region of the Democratic Republic of the Congo (DRC), the project aims to quantify forest regrowth by integrating GEDI-derived structural data with satellite and airborne laser scanner (ALS) based maps of forest height. Roy emphasized the potential of secondary and recovering forest conservation as a low-cost mechanism for carbon sequestration and climate change mitigation. GEDI data combined with satellite maps provides new opportunities to quantify forest regrowth and carbon sequestration in secondary forests at finer detail, although high species diversity and varying regrowth rates can be complex to assess with remote sensing. Roy also presented a 2025 paper validating the GEDI relative height product in the DRC and at two US temperate forest sites with a simple method to improve the GEDI canopy height using digital terrain heights measured by airborne laser scanning (ALS).
Perspectives I
After the morning CST presentation session, meeting attendees heard the first perspectives presentation from Amanda Whitehurst [NASA Headquarters (HQ] GEDI Program Scientist and NASA Terrestrial Ecology Program Manager]. Whitehurst is new to the GEDI Program Scientist role; she used this opportunity to officially introduce herself to the ST and expressed her enthusiasm for the work ahead She commended the GEDI team on the impressive accomplishments of the mission to date, and spoke about the exciting potential for continued data collection and scientific discovery through the program.
Matteo Pardini [DLR] shared his perspective on the potential of combining synthetic aperture radar (SAR) with lidar data to improve four-dimensional (4D) forest structure mapping. He highlighted DLR’s TerraSAR-X and TanDEM-X missions, which have been acquiring interferometric data since 2007 and 2010, respectively. Both missions are expected to continue acquiring data through 2028. The TanDEM-X Global Digital Elevation Model, covering 150 million km2 (58 million mi2) with approximately 1-m (3-ft) accuracy, can be used to derive forest height and biomass. The fusion of TanDEM-X and GEDI data can improve biomass estimates – see Figure 2 – and help researchers parameterize the relationship between coherence and forest structure. Pardini also previewed the upcoming BIOMASS mission, which will operate at a lower frequency and be able to penetrate vegetation, providing complementary information to the TerraSAR-X and TanDEM-X missions.
Figure 2. Biomass estimates over the Amazon basin at 25-m (82-ft) resolution derived using a fusion of data from NASA’s GEDI and DLR’s TanDEM-X missions. Figure credit: Wenlu Qi CST Presentations – Session II
Chris Hakkenberg [University of California, Los Angeles (UCLA)] opened the second CST presentation session with a discussion on his research using GEDI to characterize fuel structure, burn severity, and post-fire response across the regions of California affected by wildfire. He began by highlighting significant land cover changes resulting from wildfires in recent years that are visible as enormous [greater than 100 km2 (38 mi2)] conversions from forest to grass/scrub in the National Land Cover Dataset. Hakkenberg’s project aims to examine the role of fuel structure in driving fire severity patterns, improve burn severity maps using GEDI for change detection, and characterize post-fire response using data from Landsat 5, 7, and 8 and GEDI. He noted that while fire behavior is heavily dependent on weather, topography, and fuels – only fuels can be actively managed. GEDI provides valuable insights into forest fuel structure by measuring canopy volume (total fuel quantities) and vertical continuity (how fire may spread through those volumes). Hakkenberg and his team found that vertical fuel continuity metrics were stronger predictors of severity than fuel volume, especially in extreme weather conditions, and are most closely related to the high-burn severities that can delay long-term recovery. Finally, Hakkenberg presented research that combines GEDI and Landsat to improve burn severity assessments, which will be the focus on the next phase of this research project.
Sean Healey [U.S. Forest Service (USFS)—GEDI Co-I] presented an overview of the Online Biomass Inference using Waveforms and iNventory (OBI-WAN) project. OBI-WAN provides globally consistent estimates of biomass and carbon, as well as changes in these estimates over time, for user-defined areas and periods of interest rather than fixed 1-km (0.62-mi) squares. The project leverages GEDI L4A models to predict biomass at the footprint level and uses this dense collection of footprints to create local-level biomass models with Landsat (assuming consistent calibration of Landsat through time). To quantify uncertainty in change estimates, OBI-WAN employs a statistical method called bootstrapping, which can be embedded into customized accounting systems through a powerful programming interface accessed through Google Earth Engine.
Data Product Status I
Michelle Hofton [UMD—GEDI Co-I] and Sarah Story [GSFC] returned to the topic of GEDI data product status. They presented an update on the GEDI L2A product, which includes ground topography and canopy height measurements. Encouragingly, preliminary testing shows that GEDI’s post-storage performance has remained consistent with pre-storage. Hofton explained GEDI observations are compared with high-quality intersections with the Land, Vegetation, and Ice Sensor (LVIS) (an airborne lidar) data in order to assess GEDI data quality and accuracy. She highlighted the use of bingos – pairs of GEDI waveforms believed to be spatially coincident in vegetated areas – as a valuable tool for assessing geolocation and waveform errors as well as algorithm performance. As of December 2024, more than one million bingos had been collected. Hofton and Story concluded with a preview of anticipated updates to the L2A product for V3.0, including new quality flags for data cleaning and a refined algorithm selection approach.
John Armston [UMD—GEDI Co-I] presented on GEDI L2B data, which provides gridded footprint-level [25-m (82-ft) resolution] metrics such as canopy cover (see Figure 3), plant area index (PAI), plant area volume density (PAVD), and foliage height diversity (FHD). Waveform analysis will remain largely unchanged from V2.0. He shared that the upcoming V3.0 release will differ from V2.0 in that it will use GEDI-derived canopy-ground reflectance ratios — rather than values derived from NASA LVIS — to estimate canopy cover, thus allowing for spatial variability. Waveform analysis will remain largely unchanged from V2.0. Armston also presented 1-km (0.62-mi) leaf-on and leaf-off gridded L2B canopy cover fraction maps using both pre- and post-storage data (April 2019–November 2024), explaining how post-storage data were used to fill gaps. Additionally, the mission team has mapped GEDI canopy cover distributions using a H3-indexing API developed by Tiago de Conto [UMD], which are being used to improve GEDI L2A algorithms for ground detection. V3.0 will offer a more direct measure of canopy structure to complement L2A relative height metrics by improving quality flags and including relative canopy height metrics. Finally, the team presented progress on the independent validation of GEDI L2B V3.0 algorithms and products using the GEDI FSBD and NASA LVIS campaign data from Costa Rica, Gabon, French Guiana and the United States.
Figure 3. GEDI L2B leaf-on canopy cover fraction map derived from data obtained April 2019–October 2024. Figure credit: John Armston Jamis Bruening [UMD] shared the final data product update of the day. He discussed GEDI’s L4B gridded aboveground biomass density (AGBD) product, which is a 1-km (0.62-mi) raster dataset representing area-level estimates of mean AGBD and associated uncertainty across the mission’s range of observation. GEDI’s L4B estimates are derived from the footprint-level L4A AGBD predictions through one of two statistical modes of inference. Currently, hybrid estimation is used to generate L4B. This approach uses GEDI data as the sole input and requires at least two GEDI tracks in a 1-km (0.62-mi) grid cell to produce a mean estimate. The hybrid estimator also provides a standard error, accounting for both model variance in the L4A predictions and GEDI’s sampling uncertainty. To address gaps in GEDI’s coverage where hybrid estimates cannot be produced, the team has begun implementing an alternative inference mode, called generalized hierarchical model-based (GHMB) estimation. GHMB incorporates auxiliary imagery, such as Landsat, SAR, and GEDI’s L4A predictions, to infer mean biomass and its standard error. Although the addition of post-storage data has increased GEDI’s coverage, GHMB remains essential for producing a complete, gap-free 1-km (0.62-mi) AGBD map. Both hybrid and GHMB approaches will soon be used together to generate a global, gap-free L4B product. Users can expect the release of V3.0 L4B estimates – featuring hybrid and GHMB models of biomass inference using both pre- and post-storage data – later in 2025.
What’s Next?
Day one concluded with John Armston, who presented on the potential new satellite laser altimetry mission called Earth Dynamics Geodetic Explorer (EDGE), which was competitively selected for a Phase A Concept Study under NASA’s Earth Systems Explorer Announcement of Opportunity. If selected, EDGE would launch in 2030 and operate for a two-year mission, providing a critical link between current and future satellite laser altimetry missions.
Armston explained that EDGE addresses two of the targeted observables identified in the 2017 Earth Science Decadal Survey – terrestrial ecosystem structure and ice elevation. It provides a dramatic improvement in coverage and resolution over current active missions by operating in a Sun-synchronous orbit that will enable the direct measurement of change in the three-dimensional (3D) structure of vegetation and the surface topography of ice at the spatial and temporal scales needed to observe the driving processes. EDGE will provide fine-scale detail of ecosystem structure in some of the world’s most critical and challenging-to-quantify regions, including the boreal, transforming the field’s understanding of global terrestrial ecosystem structure and its response to natural and anthropogenic change over all of Earth’s wooded ecosystems.
DAY TWO
Data Product Status II/Extended and Demonstrative Products I
Jim Kellner began day two with an L4A footprint-level AGBD product update. His presentation focused on current product status and planned evaluation of and improvements to the L4A algorithm. Since the last STM, L4A V2.1 was updated to include data through MW 311 (through November 2024) and is now available to end users. V3.0, along with an updated Algorithm Theoretical Basis Document (ATBD), is expected later in 2025. The revised ATBD will outline enhancements to the waveform simulator, quality filtering, stratification, and model selection thanks in part to the availability of on-orbit data. V3.0 will also benefit from the ingestion of approximately 35% more simulated waveforms that passed quality assurance and quality control in the FSBD, significantly expanding training data coverage, particularly in Africa and North America. Kellner noted that users should be aware of key differences between L2 and L4 quality flags; L4 flags account for factors such as sensitivity, water presence, urban conditions, and phenology. Additionally, updates to the selected models may lead to changes in AGBD estimates, which will be more clearly communicated in the V 3.0 release. Comparing pre- and post-storage data, Kellner and his team found that AGBD estimates remain stable across both periods. He encouraged users to review the updated ATBD upon release to fully understand the changes and their implications.
Tiago de Conto [UMD] presented the new GEDI L4C WSCI product, which was released in May 2024 and available through the ORNL DAAC – see Figure 4. This footprint-level metric captures the amount and variability of canopy structure in 3D space, reflecting the richness of structural information underlying any given GEDI observation. It synthesizes multiple structural attributes into a single metric and incorporates elements of both vertical and horizontal variability. WSCI models are trained at the PFT level (i.e., deciduous broadleaf trees, evergreen broadleaf trees, evergreen needleleaf trees, and the combination of grasslands, shrubs, and woodlands) using crossovers of GEDI and airborne lidar point clouds. While WSCI tends to scale with canopy height, the relationship varies across biomes. Looking ahead, de Conto previewed forthcoming WSCI–SAR fusion work designed to produce wall-to-wall maps that are suitable for applications, such as change detection. Early fusion results using data from the European Union’s Copernicus Sentinel-1 (a synthetic aperture radar mission) and the Japan Aerospace Exploration Agency’s (JAXA) Advanced Land Observing Satellite Phased Array L-band Synthetic Aperture Radar (ALOS-PALSAR) show stable prediction performance across different biomes and time periods as well as consistent performance against airborne lidar wall-to-wall reference data.
Figure 4. The global frequency distribution of GEDI L4C Waveform Structural Complexity Index. Figure credit: Tiago de Conto Paul May [South Dakota School of Mines and Technology] presented his work predicting interpolated waveforms, along with their associated uncertainties, over USDA Forest Inventory and Analysis (FIA) field plots across the contiguous United States (CONUS). This project aims to develop regression models that convert GEDI’s waveform data into measurements of key forest attributes and enhance monitoring capabilities for a variety of applications. The resulting data product – GEDI-FIA Fusion: Training Lidar Models to Estimate Forest Attributes – was released June 2025 and is publicly available through the ORNL DAAC.
Sean Healey presented ongoing work on the GEDI L4D Imputed Waveform product, led by postdoctoral researcher Eugene Seo [Oregon State University]. This product aims to generate a wall-to-wall 30-m (98-ft) resolution map of GEDI waveforms across the globe in 2023. To achieve this, Seo, Healey, and Zhiqiang Yang [USFS] are using a k-nearest neighbor (k-NN) imputation approach to address areas without GEDI observations. The model operates at a 10-km (6-mi) scale but draws neighbors from a surrounding 30×30 km (19×19 mi) window. The resulting 30-m (98-ft) resolution imputed waveform map is aligned with Landsat data from 2023. Users can expect the release of the L4D product later in 2025.
GEDI Applications and Perspectives II
Neha Hunka [European Space Agency] shared her work using GEDI to fill gaps in the Republic of Sudan’s National Forest Inventory (NFI) in support of their Forest Reference Level (FRL) report to the United Nations Framework Convention on Climate Change (UNFCCC). Using existing NFI data for calibration, Hunka and colleagues developed a geostatistical model-based approach that interpolates between NFI sample units, allowing predictions of AGBD to be made in areas of interest – see Figure 5. (Hunka was lead author on a 2025 paper in Remote Sensing of Environment that describes a similar approach to what she described in this presentation.) UNFCCC called for the modeling approach to be transparent and replicable. Hunka emphasized the importance of access to and preparation of covariate data and called for greater capacity-building and knowledge-transfer support to help other countries adopt GEDI in their reporting. Sudan’s submission marks the first time GEDI data has been used in an FRL report.
Figure 5. A geostatistical model-based approach uses data from the Republic of Sudan’s National Forest Inventory (NFI) for calibration and interpolates between NFI sample units, allowing predictions of aboveground biomass density where desired. Figure credit: Neha Hunka Forests cover about 30% of Earth’s land area, store over 80% of terrestrial biomass and carbon, and absorb around 30% of anthropogenic carbon dioxide (CO₂) emissions. While storing carbon in forests can help mitigate carbon emissions, deforestation, disturbances, shifting global economy, and low confidence in forest carbon credits add risk and uncertainty to this strategy. By monitoring forest biomass, some of these risks can be alleviated. Stuart Davies [Smithsonian Institution] joined the STM to present his work on GEO-TREES, a global forest biomass reference system aiming to provide high-quality, publicly available ground data from a network of long-term forest inventory sites to improve biomass mapping on the global scale. Despite many Earth observing (EO) missions focused on forest biomass, a lack of standardized ground reference data has hindered accurate validation. GEO-TREES addresses this need, by fostering collaboration between carbon monitoring, biodiversity research, and EO communities. The project includes 100 core sites and 200 supplementary sites across tropical and temperate regions, selected to represent environmental and human-use gradients, with greater emphasis on sampling in the tropics. Each core site follows Committee on Earth Observation Satellites (CEOS) protocol and includes three types of measurements: forest plot inventory plot, terrestrial laser scanning, and ALS.
CST Presentations – Session III
Atticus Stovall [GSFC] shared first-year findings from his research on post-fire disturbance forest recovery in Mediterranean ecosystems – specifically Spain and Portugal – where the frequency and intensity of wildfires have significantly increased in the 21st century. Using Iberian Forest Inventory ALS data and GEDI footprint data, Stovall and his team showed that GEDI can be used to assess post-fire change as well as evaluate degradation patterns from increasing fire recurrence and intensity. Stovall shared examples demonstrating the use of GEDI to detect both immediate fire effects as well as recovery after disturbance, including stand-replacement and understory clearing. By overlaying disturbance maps with GEDI data, the team observed that recovery rates differ across height class. Looking forward, they plan to investigate how recovery rates vary across environmental gradients and incorporate field plot data to validate their findings.
KC Cushman [ORNL] presented on biomass calibration and validation (cal/val) activities for the NISAR mission, which launched in July 2025. She outlined the general approach to the NISAR biomass algorithm, which uses multiple observations from NISAR every year to produce annual biomass estimates at 1-ha (0.004 mi2) resolution. Cal/val efforts will use ALS to link sparse field data to larger landscapes with estimates at two or more sites in 15 different ecoregions. NISAR has supported cal/val field plot data collection in Spain, South Africa, and various National Ecological Observatory Network (NEON) sites in addition to ALS campaigns at Agua Salud, Panama, near the Los Amigos Biological Station, Peru, in the Chaco ecosystem, Argentina, and near Madrid, Spain.
Chi Chen [Rutgers University] presented his work exploring vertical acclimation of vegetation canopy structure and photosynthetic activities using GEDI data. Chen’s research aims to generate gap-free, high-temporal-frequency canopy profile data and to develop a novel framework that integrates GEDI observations into a multi-layer canopy process model. By training a random forest model with spatially discontinuous GEDI PAVD profiles and multiple features, e.g., multiband spectral reflectance, tree height, and forest type, Chen and his team successfully estimated spatially continuous PAI profiles across different canopy heights. The team cross-validated their predicted PAI with GEDI PAI, NEON PAI, and LAI measurements from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on NASA’s Terra and Aqua platforms. These data could be used to study seasonal variation in different canopy heights. Using a Global Multilayer Canopy OPTimization (GMC-OPT) model, they also found that GEDI-informed data has the potential to identify the vertical position of “net” seasonal leaf turnover – ultimately improving the accuracy of estimates of carbon and water fluxes.
CST Presentations – Session IV
Marcos Longo [Lawrence Berkeley National Laboratory (LBNL) in transition to Brazilian National Institute for Space Research (INPE)] and his team presented a proposed project that integrates GEDI data with process-based models to assess the impact of wildfires on forest structure, recovery, and ecosystem function. As western US forests face increasing wildfire risk due to drier climates, more human ignitions, and a legacy of fire suppression, changes in forest structure, composition, and function are likely to become more detectable over time. This project, under the leadership of Robinson Negron Juarez [University of California, Irvine and LBNL—PI] aims to quantify biomass changes in mixed conifer forests across California, Oregon, and Washington using both ALS and GEDI data. The team plans to use GEDI L2A and L2B data to assess immediate fire impacts on forest structure, investigate post-fire forest recovery, and establish relationships between forest structure and fire intensity/severity. This information will inform process-based models – e.g., the U.S. Department of Energy’s Functionally Assembled Terrestrial Ecosystem Simulator (FATES) – and support a better understanding of forest resilience under fire disturbance regime changes.
Ovidiu Csillik [Wake Forest University] presented work using GEDI and ALS to investigate biomass and structural changes in tropical forests. The work, conducted with Michael Keller [NASA/ Jet Propulsion Laboratory (JPL), USFS—PI], aims to use models to quantify changes in tropical forest biomass and evaluate understanding of topical forest productivity drivers. The project will use ALS data from over the Brazilian Amazon and other sites in Brazil, Gabon, French Guiana, Costa Rica, Mexico, and Borneo alongside GEDI data over pantropical regions around the globe. Csillik and Keller are currently conducting ALS–ALS and GEDI–GEDI comparisons, and are planning to estimate aboveground biomass change from ALS–ALS, ALS–GEDI, and GEDI–GEDI comparisons at both regional and pantropical scales from 2008–2026.
Zhenpeng Zuo [Boston University (BU)] presented his team’s research, led by Ranga Myneni [BU—PI], using mechanistic model-GEDI integration to map potential canopy top height (pCTH) and inform forest restoration planning. Predicting restoration potential is challenging, as empirical, deep-learning, and mechanistic methods vary in their accuracy, interpretability, and spatial detail. This project uses a mechanistic model based on water use and supply equilibrium, calibrated using GEDI canopy height metrics, to predict pCTH. The team found this approach produced robust pCTH predictions and shows that the Eastern US has vast restorable areas. Future work will expand to dynamic modeling to incorporate disturbance risks and effects under different climate scenarios.
DAAC Reports
Rupesh Shrestha [ORNL DAAC] presented the status of GEDI L3 and L4 datasets at the ORNL DAAC – see Figure 6. Since the 2023 STM, three new datasets have been released: L4B (country-level summaries of aboveground biomass), L4C (footprint level waveform structural complexity index), and a GEDI-FIA (fusion dataset for training lidar models to forest attributes). In total, almost 34,000 unique users have downloaded GEDI L3 and L4A-C data 13,770,648 times, with L4A being the most popular at 13.1 million downloads. As of April 30, 2025, all GEDI footprint-level datasets from L1–L4 are available with data through mission week 311 (November 2024), besides L4C. Users can look forward to a GEDI L4D Imputation Dataset later in 2025 along with the much-anticipated V3.0 GEDI data product release. All levels of GEDI data can now be accessed in one place through the NASA Earthdata Search and Data Catalog. In addition to the data products themselves, data tools and services, publications citing GEDI data and GEDI data tutorials and workshops can be found at the ORNL DAAC website. The ORNL DAAC provides data user support through the Earthdata Forum, or via their email uso@daac.ornl.gov.
Figure 6. GEDI L3 and L4B data projected on NASA WorldView/GIBS API. Explore the program here. Figure credit: Rupesh Shrestha Jared Beck [Land Processes Distributed Active Archive Center (LP DAAC)] presented on GEDI data products at the LP DAAC, a USGS–NASA partnership that archives and distributes lower-level GEDI products (GEDI L1B, L2A, and L2B). The LP DAAC has distributed over seven petabytes of GEDI data so far, and is now exclusively distributing GEDI data through NASA’s Earth Data Cloud. GEDI L2A is the most popular of the products in terms of terabytes of distribution. Like the ORNL DAAC, data user support also flows through the NASA Earthdata Forum. Tutorials can be found on GitHub. All levels of GEDI data can now be accessed in one place through the NASA Earthdata search and data catalog options.
GEDI Extended and Demonstrative Products II
Scott Goetz [NAU] discussed his team’s research leveraging GEDI data for biodiversity applications, emphasizing its potential to help improve species distribution models and the high value of understanding forest structure for conservation assessments. He highlighted a 2022 Nature Ecology & Evolution article showing that forests with higher structural integrity and cover reduced the extinction risk for over 16,000 threatened or declining species. Another 2023 study in Nature demonstrated how biodiversity indicators, such as habitat cover, canopy structure, and human pressures, can influence the effectiveness of protected areas. In order to have a wider variety of gridded products to work with for species distribution models, Pat Burns [NAU], Chris Hakkenberg, and Goetz developed the Gridded GEDI Vegetation Structure Metrics and Biomass Density at Multiple Resolutions product that has been released through the ORNL DAAC and Google Earth Engine along with a data descriptor paper published in a Nature Scientific Data paper – see Figure 7. Burns elaborated that, relative to fusion products, gridded GEDI products performed better when measuring structure, especially in the understory. The team is now comparing species distribution models in mainland Southeast Asia using fusion versus solely GEDI data.
Figure 7. GEDI mean foliage height diversity (FHD) map using shots from April 2019 to March 2023 at 6-km (4.7-mi) spatial resolution. Red boxes indicate the approximate location of airborne lidar used for intercomparison. Three insets show GEDI mean FHD at finer spatial resolution [1 km (0.62 mi)] as well as more detailed airborne lidar coverage (red polygons). From left to right the insets show: Sonoma County, California, Coconino National Forest, Arizona, and Sumatra/Borneo. Figure credit: From Patrick Burns et al (2024) Nature Scientific Data Perspectives III
STM attendees concluded day two with a perspective talk from Marc Simard [JPL], who showcased a range of studies demonstrating diverse applications of GEDI data, opportunities for its improvement, and potential for informing future scientific research. Drawing on his own work, Simard shared examples of using GEDI data for cal/val of global Digital Elevation Measurement (DEM) and Digital Terrain Model (DTM), mapping global mangrove heights, monitoring forest growth, and analyzing hydrological processes. In more detail, he explained how he led the development of a 12-m (39-ft) spatial resolution global mangrove height product using GEDI and TanDEM-X data. Additionally, he discussed a study evaluating tree growth rates in the Laurentides Wildlife Reserve in Quebec, Canada using both GEDI and ALS. The analysis revealed an average growth rate of approximately 32 ±23 cm (12 ±9 in) per year. Finally, he presented a paper under review examining water level detection and hydrological conditions in coastal regions using GEDI alongside Ice, Cloud, and land Elevation Satellite 2 (ICESat-2) data. In closing, Simard emphasized that GEDI datasets can help identify critical data and knowledge gaps, guiding the development of new missions – e.g., the Surface Topography and Vegetation (STV) mission concept called for in the 2017 Earth Science Decadal Survey report. As described in the STV Study Team Report, the mission would focus on elevation and vertical structure to study the solid Earth, cryosphere, vegetation structure, hydrology, and coastal geomorphology.
DAY THREE
CST Presentations – Session V
Jody Vogeler [Colorado State University] opened the final CST presentation session with an overview of her research using GEDI data fusions to characterize post-fire landscapes and understand habitat refugia for the threatened Canada lynx (Lynx canadensis). This project builds on her team’s phase-I work, which produced 30-m (98-ft) resolution gridded GEDI fusion maps across six Western U.S. states to support habitat and diversity applications related to cavity-nesting birds, small mammals, and carnivore–prey relationships. The team is now focusing on validating and improving their GEDI fusion products within post-disturbance landscapes, specifically post-fire. Using this data, Vogeler and her team aim to better understand how post-fire structural information from GEDI improves their ability to understand lynx behavior–habitat relationships across early post-fire landscapes. This information can help evaluate what structural attributes determine post-fire refugia patch use by lynx. Next steps for this work include integrating GEDI V3.0 data upon its release, identifying new GEDI metrics and derived products, and incorporating lynx radio-collar data into their analyses. Vogeler also presented her work as co-PI on a NASA Ecological Conservation Project in Greater Kruger National Park, South Africa, where she and her team are developing spatial monitoring tools to support management and conservation planning.
Jingfeng Xiao [University of New Hampshire] provided updates on his team’s research using GEDI data to understand how structural diversity influences productivity and carbon uptake of forests in the United States. The project aims to assess GEDI’s ability to quantify structural diversity, investigate how that diversity regulates forest productivity and carbon uptake, and understand its role in resilience of forest productivity to drought. When analyzing the relationships of gross primary production (GPP) and evapotranspiration (ET) with canopy structure metrics, the team found that increased canopy structure complexity positively affected GPP and ET and reduced their seasonal variability. They also found that greater canopy complexity improved ecosystem resistance to drought. As part of the project, the team also produced 1-km (0.62-mi) resolution gridded maps of GPP and ET.
Lei Ma [UMD] delivered the final talk of the STM, presenting his project that integrates GEDI observations with mechanistic ecosystem modeling to quantify forest regrowth in a changing climate. Ma used GEDI data and the Ecosystem Demography (ED) model in his research and found that height and aboveground biomass (AGB) regrowth rates can be derived by combining GEDI and land-use and land-cover change data. Ma found that regrowth rates derived from different inputs are generally consistent at large scales but variable at fine scales. Notably, regrowth rates showed temporal dependence, decreasing by roughly 50% every decade. Lastly, Ma and his team found that spatial variation in height and AGB regrowth rates can be partially explained by environmental conditions and disturbance frequency.
Conclusion
The 2025 GEDI STM was especially exciting, as it came on the cusp of post-storage data being processed and released as V2.1. Additionally, it marked the first time the new CST cohort presented on their research and joined breakout sessions with the wider GEDI team. The meeting highlighted the mission’s ongoing success and scientific value following hibernation on the ISS. Looking ahead, data users can anticipate the V3.0 product release later in 2025.
Talia Schwelling
University of Maryland College Park
tschwell@umd.edu
Share
Details
Last Updated Aug 18, 2025 Related Terms
Uncategorized Earth Science View the full article
-
By NASA
Explore This Section Earth Earth Observer Editor’s Corner Feature Articles Meeting Summaries News Science in the News Calendars In Memoriam Announcements More Archives Conference Schedules Style Guide 12 min read
Summary of the 54th U.S.–Japan ASTER Science Team Meeting
Introduction
The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Science Team (ST) organized a three-day workshop that took place June 9–11, 2025, at the Japan Space System’s (JSS) offices in Tokyo, Japan. About 25 people from Japan and the United States participated during the in-person meeting – see Photo 1.
U.S. participants included representatives of NASA/Jet Propulsion Laboratory (JPL); two universities – University of Arizona (UA) and University of Pittsburgh (UPitt); and Grace Consulting. Japanese participants represented JSS, the Geologic Survey of Japan (GSJ), National Institute of Advanced Industrial Science and Technology (AIST), National Institute for Environmental Studies (NIES), and the Remote Sensing Technology Center of Japan (RESTEC). Participants from Ibaraki University (IU), Nagoya University (NU), University of Tokyo (UT), and University of Tsukuba (Uts) also joined.
Photo 1. Several attendees sit for a photo at the 54th ASTER Science Team meeting at the Japan Space System’s offices in Tokyo, Japan. Photo credit: Osamau Kashimura The main objectives of the 54th ASTER STM were to:
discuss impacts of the proposed NASA budget reductions for Fiscal Year (FY) 2026; respond to plans for future impacts on ASTER from possible power reductions on the Terra platform; receive updates on data acquisition status, data calibration and validation (cal/val) activities, data distribution plans, and applications using ASTER observations; and discuss the end-of-mission plans for Terra and ASTER and archive documentation requirements. The remainder of this article summarizes the highlights from the meeting, which includes an overview of the opening plenary session and summaries of the four working group sessions. A brief review of the closing plenary, which included summary reports from the chairpersons of all working groups, rounds out the report, followed by some overall concluding thoughts.
Opening Plenary Session
Yasushi Yamaguchi [NU—Japan ASTER ST Lead] and Michael “Mike” Abrams [JPL—U.S. ASTER ST Lead] welcomed participants and reviewed the agenda for the opening plenary and the schedule for the working group sessions.
Abrams presented highlights of science results based on ASTER data. He also discussed some issues that Woody Turner [NASA Headquarters—ASTER Program Scientist] had raised, including NASA’s response to the President’s proposed fiscal year (FY) 26 budget and the status of FY25 funding. Abrams reported that Terra passivation is currently scheduled for February 2027 and described Terra’s power status. [UPDATE: If the President’s proposed FY26 budget goes into effect without modification by Congress, the three Flagship missions will enter accelerated Phase F (closeout); Terra passivation would start in November 2025 and be complete by March 2026.]
Abrams reviewed the status of the Terra spacecraft, showing slides provided by Jason Hendrickson [GSFC]. The Flight Operations Team staffing remains constant. Science data capture for ASTER remains above 99%. The impact of the shunt failure on November 28, 2024 required the safe halting of the instrument. Visible-near-infrared (VNIR) observations resumed in mid-January, and thermal infrared (TIR) observations resumed in mid-May. Collision avoidance events continue to be part of normal operations.
Hitomi Inada [JSS] provided a status report on the ASTER instrument. Many of the monitored components (i.e., VNIR pointing motor) are beyond their original useful life in orbit, but the aging hardware shows no signs of wearing out or a decrease in performance. She showed data that indicated that the temperature and current telemetry trends remain stable.
Abrams presented ASTER product distribution statistics provided by Cole Krehbiel [Land Processes Distributed Active Archiver Center (LP DAAC]). The ASTER Digital Elevation Model continues to be the most ordered product among all users of ASTER data. As defined by the ST at the last meeting, most ASTER data products [e.g., Version 4 (V4) products] are being created and placed in a searchable/orderable archive that can be accessed through NASA’s Earthdata tool. Abrams reported that the LP DAAC started producing these files in January 2025 and will be finished before August 2026.
Koki Iwao [GSJ] presented AIST’s product distribution statistics. Over 4.7 million scenes have been acquired and processed to Level 1A (L1A) since June 10, 2025. AIST continues to distribute ASTER’s pseudo-natural color scenes in keyhole mark-up language (KML – a file format used to display geographic data) and scene-based Digital Elevation Models. The largest number of users of Japanese products are from the United States.
Tetsushi Tachikawa [JSS] summarized the status of ASTER observations since the beginning of the mission. He reported that all of the global observation programs are functioning normally, acquiring data as planned. Updates to the observation programs will be considered by this week’s working groups. Tachikawa also added that the change of the orbit repeat – after Terra’s October 2022 exit from the Morning Constellation – has been accommodated in the ASTER scheduler.
Abrams presented a report on behalf of Simon Hook [JPL], who was unable to attend the meeting. Hook’s information provides a status update for the multispectral TIR instrument on NASA’s ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) mission. Abrams also spoke about NASA’s future Surface Biology and Geology (SBG) mission, which is part of the planned Earth System Observatory.
Applications Working Group
The applications session provided a sampling of how ASTER data are used. A few examples are highlighted below. The second half of the session was devoted to a discussion of end-of-mission documentation requirements. This included a review of the NASA guiding document and sharing of existing documents.
Michael Ramsey [UPitt] presented work on forecasting volcanic activity with the ASTER long-term archive. His team developed a statistical detection code to extract accurate temperature anomalies for five test volcanoes over 25 years. They used these results to train a deep learning approach for anomaly detection in future TIR data. The method showed 73% success for Piton del la Fournaise volcano, Réunion island, and near 100% success for Sheveluch volcano, Kamchatka Krai, Russia.
Miyuki Muto [IU] reported on waste volume changes in 15 open landfills in developing countries using more than 20 years of ASTER time-series digital surface models – see Figure 1. The method was found to be consistent with reports using synthetic aperture radar (SAR) data, which dates to 2016. Thus, ASTER can provide a longer time series for future optical or radar studies.
Figure 1. Time variation in the relative volume of waste for landfills, obtained from ASTER time-series digital surface model data for the four Indian sites – Ghazipur, Bhalswa, Okhla, and Deonar. Figure credit: Figure taken from Muto and Tonooka (2025), Sensors Mike Abrams presented the 25-year history of ASTER data applied to geologic mapping and mineral exploration. He explained how the first published papers appeared a few years after launch and validated the unique mineralogical information contained in the ASTER data. Over the following 20 years, several reports from mineral exploration companies announced the discovery of gold, chromite, and lithium deposits, which were found largely based on analysis of ASTER data.
Calibration/Validation Working Group
The Calibration/Validation (cal/val) working group is responsible for monitoring the radiometric and geometric performance of ASTER’s VNIR and TIR instruments. Three different cal/val techniques are used including: analysis of onboard calibration lamps, comparison with onboard blackbodies, and measurements of pseudo-invariant ground targets during field campaigns. The L2 software algorithms are being updated for the final, archival processing which is anticipated to be completed in May 2026.
Bjorn Eng [JPL] reported that the newest version of the L2 algorithm for ASTER VNIR and TIR cal/val was delivered to the LPDAAC for ingest and testing. Eng explained how the new software includes Modern-Era Retrospective Analysis for Research and Applications, Version 2 (MERRA-2) data, which allows users to create atmospheric profiles for temperature, pressure, water vapor, and ozone. MERRA-2 is an improvement – both spatially and temporally – over the National Centers for Environmental Prediction’s Global Data Assimilation System that is used in the original MERRA. The new L2 production algorithms were validated, and the LP DAAC began incorporating the algorithms into the static archive in January 2025.
Mike Abrams presented on behalf of Cole Krehbiel [LP DAAC] and reported on the assessment of geometric performance of the L1 processing software, which was updated to the new Landsat ground control point library. He also presented an improved global digital elevation model. The ASTER final processing campaign uses the improved control point library.
Satoru Yamamoto [GSJ] presented updates to the calibration trends of the onboard VNIR lamps. Two onboard calibrations were performed on September 20, 2024 and November 8, 2024. Several analyses of the calibration lamps showed no significant change in the data trends – see Figure 2. The signal-to-noise ratios are still greater than the requirement of 140.
Figure 2. Onboard lamp calibration data for Bands 1, 2, and 3. The lamp data show no significant change in the three bands after updating the calibration. Figure credit: Satoru Yamamoto Soushi Kato [RESTEC] presented results from his September 2024 field campaign in Nevada and Utah. The campaign was marked by clear weather during ASTER’s day and night overpasses. Kato compared his in situ TIR measurements with the standard ASTER temperature products from the LP DAAC. The agreement for the five AESTER TIR bands was within ± 1.5 K.
Hideyuki Tonooka [IU] presented the results of his TIR field calibration campaigns at the same time and location as those conducted by Kato (described in previous presentation summary). Additionally, he reported that several calibration campaigns conducted at Lake Kasumigaura, Japan were cancelled due to cloudy weather, which led to the suspension of ASTER data acquisition. Tonooka compared his in situ TIR measurements with the standard ASTER temperature products from the LP DAAC. The agreement for the five ASTER TIR bands was within ± 1.3 K, except for band 10 at the Utah site where the discrepancy was -2.3 K.
Temperature–Emissivity Working Group
This group focuses on ASTER’s kinetic temperature and emissivity products, as well as application of these products and review of the nighttime TIR global mapping program status.
Mike Abrams presented his analyses of the ASTER Level-2 Surface Kinetic Temperature Product (AST_08) for a nighttime scene acquired over Lake Tahoe, CA. He compared the on-demand MERRA-2 product from NASA’s Global Modeling and Assimilation Office with the archive-produced product. The comparison showed that the two products were identical, pixel-by-pixel. Abrams conducted a second analysis to compare the archived MERRA_2 AST_08 product with the on-demand Moderate Resolution Imaging Spectroradiometer (MODIS) AST-08 product to assess the difference in temperature due to improved MERRA-2 atmospheric parameters. The MERRA-2 product had lower temperature values for higher elevations and higher values for lower elevations with more column water vapor – see Figure 3. This result is physically correct and validates the improvement using MERRA-2 atmospheric data.
Figure 3. Colorized difference by temperature, in Kelvin, between the product using MERRA-2 and MODIS atmospheric values: blue -1.0 to -0.6; green -0.5 to -0.1; red 0.0; and yellow 0.1 to 0.5. Figure credit: Michael Abrams Hideyuki Tonooka discussed the status of installation of the JPL radiometer at Lake Kasumigaura. The plan is to mount the radiometer on an existing observation in the middle of the lake. The radiometer will be operated jointly by JPL and IU. The installation is planned to start in the Summer 2025.
Tetsuchi Tachikawa reviewed the status of the current Thermal Global Mapping acquisition program to acquire cloud-free TIR nighttime images over most of the Earth’s land surface. He explained that the program is refreshed every year, with most recent refresh beginning May 2025.
Operations and Mission Planning Working Group
The Operations and Mission Planning Working Group oversees and reviews the acquisition programs executed by the ASTER scheduler. Because ASTER data acquisitions have to be scheduled every day to accommodate ASTER’s average 8% duty cycle, ST members developed an automatic program to select 600–700 daily scenes from the possible 3000 plus images uploaded in the request archive.
Tachikawa reviewed the status of acquisition scheduling. Urgent observations receive the highest priority and can be scheduled close to acquisition time. Approximately 70 scenes are programmed per month – with over 95% acquisition success. By contrast, global mapping data acquisitions receive the lowest priority and are used to fill in the scenes for the daily quota. He explained that the goal of the ASTER is to have the instrument acquire at least one cloud-free image for every place on Earth. Due to persistent cloud cover, success is typically ~85% after several years, at which time the program is restarted. Tachikawa next gave short updates on three other acquisition programs that focus on islands, volcanoes, glaciers, and cloudy areas, respectively. The global volcano image acquisition program will continue with no change to the observation parameters. Acquisition of images of islands and over cloudy areas will also continue in current form. The global glacier acquisition program will be modified to change the VNIR gain settings to optimize images over snow and ice.
Tachikawa also discussed the effect of the ASTER shutdown in November 2024 and cessation of all ASTER data acquisitions. VNIR-only acquisitions were resumed in January 2025, and TIR acquisitions resumed in May 2025, with full operations and acquisitions of data from both VNIR and TIR instruments.
Closing Plenary Session
Each chairperson summarized the presentations, discussions, and recommendations that occurred during their respective working group session. The overall consensus maintained that the ASTER instrument is operating normally again – with no indications of any component failures. The ST is preparing to absorb the impact of the 50% budget reduction on the Flight Operation Team at GSFC. At this time, the main impact has been a small increase in lost data (1–2%) as a result of the absence of operators to attempt immediate recovery. The ST also approved plans for ASTER’s contribution to the Terra power mitigation plan, and the recommendation has been forwarded to the Terra Project Scientist and the Flight Operations Team.
Conclusion
The 54th ASTER ST Meeting successfully covered all critical issues introduced during the Opening Plenary Session. The ST worked on formulating priorities for reduction of ASTER instrument operations in response to possible future Terra power reductions. During working group sessions, participants received updates on a variety of topics (e.g., instrument scheduling, instrument performance, archiving plans, and new applications). Although this may be the last Joint U.S./Japan ASTER ST Meeting, the 55th joint meeting was tentatively scheduled for May 2026.
Acknowledgments
The lead author’s work on this article was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA.
Michael Abrams
NASA/Jet Propulsion Laboratory/California Institute of Technology
mjabrams@jpl.nasa.gov
Yasushi Yamaguchi
Nagoya University/Japan Science and Technology Agency
yasushi@nagoya-u.jp
Share
Details
Last Updated Aug 18, 2025 Related Terms
Earth Science View the full article
-
By NASA
Explore This Section Perseverance Home Mission Overview Rover Components Mars Rock Samples Where is Perseverance? Ingenuity Mars Helicopter Mission Updates Science Overview Objectives Instruments Highlights Exploration Goals News and Features Multimedia Perseverance Raw Images Images Videos Audio More Resources Mars Missions Mars Sample Return Mars Perseverance Rover Mars Curiosity Rover MAVEN Mars Reconnaissance Orbiter Mars Odyssey More Mars Missions Mars Home 3 min read
An Update From the 2025 Mars 2020 Science Team Meeting
A behind-the-scenes look at the annual Mars 2020 Science Team Meeting
Members of the Mars 2020 Science Team examine post-impact sediments within the Gardnos impact structure, northwest of Oslo, Norway, as part of the June 2025 Science Team Meeting. NASA/Katie Stack Morgan Written by Katie Stack Morgan, Mars 2020 Acting Project Scientist
The Mars 2020 Science Team gathered for a week in June to discuss recent science results, synthesize earlier mission observations, and discuss future plans for continued exploration of Jezero’s crater rim. It was also an opportunity to celebrate what makes this mission so special: one of the most capable and sophisticated science missions ever sent to Mars, an experienced and expert Science Team, and the rover’s many science accomplishments this past year.
We kicked off the meeting, which was hosted by our colleagues on the RIMFAX team at the University of Oslo, with a focus on our most recent discoveries on the Jezero crater rim. A highlight was the team’s in-depth discussion of spherules observed at Witch Hazel Hill, features which likely provide us the best chance of determining the origin of the crater rim rock sequence.
On the second day, we heard status updates from each of the science instrument teams. We then transitioned to a session devoted to “traverse-scale” syntheses. After 4.5 years of Perseverance on Mars and more than 37 kilometers of driving (more than 23 miles), we’re now able to analyze and integrate science datasets across the entire surface mission, looking for trends through space and time within the Jezero rock record. Our team also held a poster session, which was a great opportunity for in-person and informal scientific discussion.
The team’s modern atmospheric and environmental investigations were front and center on Day 3. We then rewound the clock, hearing new and updated analyses of data acquired during Perseverance’s earlier campaigns in Jezero’s Margin unit, crater floor, and western fan. The last day of the meeting was focused entirely on future plans for the Perseverance rover, including a discussion of our exploration and sampling strategy during the Crater Rim Campaign. We also looked further afield, considering where the rover might explore over the next few years.
Following the meeting, the Science Team took a one-day field trip to visit Gardnos crater, a heavily eroded impact crater with excellent examples of impact melt breccia and post-impact sediment fill. The team’s visit to Gardnos offered a unique opportunity to see and study impact-generated rock units like those expected on the Jezero crater rim and to discuss the challenges we have recognizing similar units with the rover on Mars. Recapping our Perseverance team meetings has been one of my favorite yearly traditions (see summaries from our 2022, 2023, and 2024 meetings) and I look forward to reporting back a year from now. As the Perseverance team tackles challenges in the year to come, we can seek inspiration from one of Norway’s greatest polar explorers, Fridtjof Nansen, who said while delivering his Nobel lecture, “The difficult is that which can be done at once; the impossible is that which takes a little longer.”
Share
Details
Last Updated Jul 01, 2025 Related Terms
Blogs Explore More
2 min read Curiosity Blog, Sols 4584–4585: Just a Small Bump
Article
1 hour ago
4 min read Curiosity Blog, Sols 4582-4583: A Rock and a Sand Patch
Article
3 days ago
2 min read Curiosity Blog, Sols 4580-4581: Something in the Air…
Article
5 days ago
Keep Exploring Discover More Topics From NASA
Mars
Mars is the fourth planet from the Sun, and the seventh largest. It’s the only planet we know of inhabited…
All Mars Resources
Explore this collection of Mars images, videos, resources, PDFs, and toolkits. Discover valuable content designed to inform, educate, and inspire,…
Rover Basics
Each robotic explorer sent to the Red Planet has its own unique capabilities driven by science. Many attributes of a…
Mars Exploration: Science Goals
The key to understanding the past, present or future potential for life on Mars can be found in NASA’s four…
View the full article
-
By NASA
Explore This Section Earth Earth Observer Editor’s Corner Feature Articles Meeting Summaries News Science in the News Calendars In Memoriam More Archives Conference Schedules Style Guide 19 min read
Summary of the 2024 SAGE III/ISS Meeting
Introduction
The Stratospheric Aerosol and Gas Experiment (SAGE) III/International Space Station [SAGEIII/ISS] Science Team Meeting (STM) took place on October 22–23, 2024, in a hybrid format. Approximately 50 scientists attended in person at NASA’s Langley Research Center (LaRC) – see Photo. Participants included researchers from U.S. universities, NASA LaRC, NASA’s Goddard Space Flight Center (GSFC), the NASA/Jet Propulsion Laboratory (JPL), and National Oceanic and Atmospheric Administration (NOAA) laboratories. Speakers from Canada and Germany also attended.
The history of the SAGE missions, the development and accomplishments of the SAGE III/ISS mission, and a summary of the 2022 STM appear in a previous article – see “Summary of the SAGE III/ISS Science Team Meeting,” in The Earth Observer, May–June 2023, 35:3, 11–18.
This article will summarize the content and key outcomes from the 2024 STM. The full agenda and presentations can be viewed at the SAGE III/ISS website. To access the presentations, use the link provided, then click on the Science Team tab and scroll about halfway down the page to find the 2024 meeting where they are listed.
Photo. Group photo of the in-person attendees of the SAGE III/ISS science team meeting, which took place at NASA’s Langley Research Center October 22–23, 2024. Photo Credit: NASA DAY ONE
Jun Wang [University of Iowa—SAGE III/ISS Science Team Leader] and David Flittner [LaRC—SAGE III/ISS Project Scientist] kicked off the STM. The pair welcomed all participants and invited Richard Eckman [NASA Headquarters (HQ)—SAGE III/ISS Program Scientist, now emeritus (as of January 1, 2025)] to deliver opening remarks. Allison McMahon [LaRC/Science Systems and Applications, Inc. (SSAI)—SAGE III/ISS Communications Lead] then spoke and provided logistical details for the meeting.
The morning sessions focused on project updates and the synergy between SAGE III/ISS and future missions currently in the planning phase, with potential launches in the early 2030s. The afternoon sessions were dedicated to aerosol research and the calibration/validation of SAGE III/ISS data products.
Project Operation and Data Product Briefing
David Flittner presented an update of the mission status, with over seven years and counting of data collection/analysis/release. SAGE III/ISS went through the 2023 Earth Science Senior Review (see page 15 of linked document for specific summary of the SAGE III/ISS results), and NASA HQ approved the proposal for continued operations for 2024–2026, with partial, overguide (i.e., above baseline request) funding approved to support community validation efforts, e.g., developing online quick look tools – see Figure 1 – and timely algorithm and product improvements. However, some reduction in mission staff and reorganization of work assignments have had to occur to stay within the allotted budget.
Overall, Flittner described 2024 as “a year of growth” for many on the SAGE III/ISS Team. He referenced important mission activities planned during the current three-year tenure of the new Science Team cohort. This work includes supporting the 2026 World Meteorological Organization (WMO) International Ozone assessment with a release of improved solar/lunar product in early 2025, examination of product sensitivities to variable aerosol loadings, introduction of a research product with retrieved temperature and pressure profiles, and continuing a much sought-after summer internship program.
Figure 1. An example of an enhanced tool for the community to visualize SAGE III/ISS data validation. Figure Credit: Mary Cate McKee [LaRC] Robbie Manion [LaRC] presented version 6.0 (V6) of the SAGE III/ISS data products, which were released in April 2025. Owing to a change in source ozone (O3) cross sections, this version will resolve the longstanding low bias in retrieved aerosol extinction around 600 nm. As a result, some changes in the downstream data products for inferred particle size distribution and aerosol/cloud categorization are expected. In addition, V6 will allow for recovery of hundreds of profiles previously impeded by the recent proliferation of sunspots.
Jamie Nehrir [LaRC] stated that SAGE III celebrated its seventh year onboard the ISS on February 19, 2024. [UPDATE: As of this publication, SAGE III/ISS has now passed eight years in orbit.] The payload continues to operate nominally surpassing 70,000 occultation events successfully acquired. Nehrir reported that SAGE III was not affected by the October 9, 2023, external leak from the Russian Nauka (or Multipurpose Laboratory) Module. However, the Disturbance Monitoring Package (DMP) lasers for the y- and z-axes on the instrument have been degrading. The operations team has been in a healthy dialog with the science and processing teams and external partners to determine the potential impact of these degradations on payload performance and on any ISS activities that could affect the science.
Invited Presentations on Synergy with New Limb Missions in Formulation
Lyatt Jaeglé [University of Washington] presented the mission concept for the Stratosphere Troposphere Response using Infrared Vertically-resolved light Explorer (STRIVE), which was recently selected for a competitive Phase A Concept Study within NASA’s 2023 Earth System Explorers Program (an element of the 2017–2027 Earth Science Decadal Survey). STRIVE fills a critical need for high vertical [1 km (0.6 mi)] resolution profiles of temperature, O3, trace gases, aerosols, and clouds in the upper troposphere–stratosphere (UTS). The system will provide near-global coverage and unparalleled horizontal sampling, producing 400,000 profiles each day. STRIVE will carry two synergistic instruments: a limb-scanning, infrared-imaging Dyson spectrometer to retrieve profiles of temperature, water vapor, trace gas concentrations, aerosol extinction, and cloud properties during day and night; and a dual-spectral, multi-directional, limb-profiling radiometer that retrieves detailed aerosol properties during day.
Björn-Martin Sinnhuber [Karlsruhe Institute of Technology, Germany] gave an overview of the Changing-Atmosphere Infrared Tomography Explorer (CAIRT), a candidate mission for the upcoming European Space Agency (ESA) Earth Explorer 11 satellite. If selected, CAIRT would provide passive infrared limb imaging of atmospheric temperature and trace constituents from the upper troposphere at about 5 km (3 mi) altitude up to the lower thermosphere at 115 km (71 mi) altitude. The presentation highlighted how these observations can provide information on how atmospheric gravity waves drive middle atmosphere circulation, age-of-air in the middle atmosphere, the descent of nitrogen oxides (Nox) from the thermosphere into the stratosphere, as well as the detection of sulfur species and sulfate (SO42-) aerosols in the stratosphere.
Aerosols
Mahesh Mundakkara [LaRC] presented the research used to generate the Global Space-based Stratospheric Aerosol Climatology (GloSSAC) product, a critical resource for analyzing and modeling the climatic effects of stratospheric aerosols. His presentation focused on assessing the Ozone Mapping and Profiler Suite (OMPS) limb profiler (LP) by comparing its data with other datasets, particularly SAGE III/ISS. (NOTE: While OMPS currently flies on the NASA–NOAA Suomi National Polar-orbiting Partnership (Suomi NPP), NOAA-20, and NOAA-21 platforms; LP is only part of OMPS on NOAA–21.) The evaluation aims to identify discrepancies and assess the suitability of OMPS-LP data for integration into the GloSSAC framework.
Jianglong Zhang [University of North Dakota] discussed the research plans of a newly funded SAGE project to investigate effective methods for improving stratospheric aerosol analyses and forecasts from aerosol models that can be used for future air quality and visibility forecasts and climate applications. Zhang also presented preliminary comparisons of collocated SAGE aerosol extinction and Cloud Aerosol Transport System (CATS) lidar aerosol extinction values in the stratosphere. [NOTE: CATS operated on ISS from 2015–2017.]
Sara Lu [The State University of New York, Albany] discussed efforts to examine smoke aerosol radiative effects in the upper troposphere and lower stratosphere using SAGE III/ISS observations. Lu explained that this project aims to produce multiyear analysis of aerosol radiative effects from all known pyrocumulonimbus cloud (pyroCb) events worldwide over a range of pyroCb intensities and various injection altitudes, geographic locations, and backgrounds. He presented findings from a pyroCb inventory compiled by the Naval Research Lab (NRL).
Xi Chen and Jun Wang [both University of Iowa] presented their new project on retrieving aerosol properties using SAGE III/ISS lunar measurements. They noted the challenges in normalizing lunar measurements caused by the Moon’s non-uniform surface. To address this, the team is developing a local normalization method to derive atmospheric transmissions from signals detected within each lunar event, enabling accurate aerosol retrieval. They reported that preliminary results are promising as evidenced by comparison with transmission product from collocated solar events – see Figure 2. This new processing will enrich the spatial and temporal coverage of SAGE III/ISS aerosol product by involving lunar events.
Figure 2. Preliminary results of the transmission derived from SAGE III/ISS lunar measurements (y-axis) and its comparison with collocated SAGE III/ISS solar measurements (x-axis). The comparisons are presented in two ways, one for the same wavelength color-coded by altitude [left] and another at the same altitude color-coded for the different wavelengths [right]. The results are for June 2017 through Novembe 2022, and the collocation criteria requires latitude separation smaller than 1˚ and observation times within 10 days. Note that if the transmission at any wavelength or altitude is smaller than 0.005, it is removed from the comparison for quality assurance purpose. Figure Credit: Xi Chen, University of Iowa Adam Pastorek and Peter Bernath [both Old Dominion University] discussed the properties of stratospheric SO42- aerosols from the infrared transmission spectra of Atmospheric Chemistry Experiment (ACE) – flying on the Canadian SCISAT satellite since 2003 – and optical extinction from SAGE III/ISS. Based on ACE infrared measurements, the researchers derived an empirical formula to determine the composition (weight % H2SO4) of volcanic plumes. They combined coincident ACE and SAGE III/ISS measurements, using bimodal, log-normal size distributions to reproduce the observations – see Figure 3. They used ACE observations of sulfur dioxide (SO2) to study the creation and destruction of stratospheric SO42- aerosols.
Figure 3. Combined transmittance fitting results from Atmospheric Chemistry Experiment– Fourier Transform Spectrometer (ACE-FTS), and SAGE III/ISS measurements demonstrate an improved characterization of sulfate particle size distribution using bi-lognormal (mode) distributions compared to a single lognormal distribution. The panels on the left show the transmittance fitting [top] and residuals [bottom] for the mono-mode distribution model, while the center panels show the transmittance fitting [top] and residuals [bottom] for the bi-mode distribution. The right panel illustrates the contributions of fine and coarse mode components to the total transmittance. The measurements for this figure were taken approximately four months after the January 2022 Hunga Tonga–Hunga Haʻapai eruption at a tangent height of 23.6 km (14.5 mi) in ACE occultation (ss100628), with coincident SAGE measurements from that same period (2022041609). Figure Credit: Adam Pastorek, adapted from a Figure in a paper published in Journal of Quantitative Spectroscopy and Radiative Transfer in January 2024. Sean Davis [NOAA, Chemistry Science Lab] presented on his research aimed at constraining decadal variability and assessing trends in stratospheric composition and tropospheric circulation using SAGE III/ISS and complementary satellite data sets. The team continues to include the SAGE water vapor and O3 products in the Stratospheric Water and OzOne Satellite Homogenized (SWOOSH) dataset. Davis also highlighted preliminary work evaluating V6 data in comparison to the former V5.3. He discussed line-of-sight, transmission-based filtering for O3 profiles and O3 diurnal variability corrections.
Lars Kalnaajs [University of Colorado, Boulder] presented results from two studies of particle size distributions from SAGE aerosol extinction data. Kalnaajs summarized results from two papers in review. His team paired the Optical Particle Counter collected from balloon platforms with SAGE II data to derive the parameters for bi-mode aerosol size distribution. They also presented the work of using SAGE III extinction ratios, 448/756 versus 1544/756, to derive monomodal lognormal size distribution, which allows them to compute distribution moments and compare these to in situ measurements taken over Sweden in the winters of 2002 and 2004.
Anne Thompson [GSFC, emeritus] presented on the Southern Hemisphere Additional Ozonesondes (SHADOZ) network and how that SHADOZ data are a satellite validation standard and can also be used to assess ozone trends in the upper troposphere and lower stratosphere. Thompson emphasized that SHADOZ O3 profiles are the only standard process to obtain measurements from surface to mid-stratosphere at 100–150 m (328–492 ft) resolution. Such measurements are essential to validate O3 measurements from SAGE-derived products. She also presented an update on the free tropospheric and lowermost stratospheric (LMS) O3 trends from eight equatorial SHADOZ sites. Newer calculations confirm that an apparent LMS seasonal decline (July–September) is associated with a roughly 100 m (328 ft) upward trend in tropopause height.
DAY TWO
The second day started with Jack Kaye [NASA Earth Science Division—Associate Director for Research for the Earth Science Division, emeritus as of April 30, 2025] providing a historic perspective on SAGE and comments on its context within NASA’s overall Earth science program. A technical session was held with three invited presentations, followed by three additional sessions where science team members presented their research on trace gas studies, including data product calibration and validation. The meeting concluded with updates from the SAGE project team on the SAGE III/ISS website and ongoing operations aboard the ISS. In his presentation, Kaye shared about his past involvement with the SAGE program and his perspective on its future in the context of flight missions for Earth observations.
Invited Presentations on Advanced Modeling and New Satellite Mission For UTS
Steven Pawson [GSFC] presented on the comprehensive modeling and analysis capabilities of
Upper troposphere and lower stratosphere (UTLS) dynamics and composition in the Goddard Earth Observing System (GEOS) model Pawson discussed the Global Modeling and Assimilation Office’s (GMAO) recent support for the Asian summer monsoon Chemical and CLimate Impact Project (ACCLIP) mission and the trend analysis of stratospheric O3. He also discussed future plans for GMAO, including improving the representation of water vapor in UTS through data assimilation and increasing horizontal and vertical resolution in the GEOS model.
Kostas Tsigaridis [Columbia University] presented recent research on the composition and climate impacts of increasing launches to Low Earth Orbit (LEO). Assuming that there are 10,000 launches per year and all launches use liquefied natural gas (LNG) as a propellant, the team compiled launch-related emission inventories and highlighted key uncertainties that could significantly affect climate predictions – particularly the impact black carbon has on the radiative balance and heterogeneous chemistry of the UTS. In addition, water vapor was found to contribute to the heating of the stratosphere and to a nontrivial amount of O3 depletion – 13 Dobson units (DU) on the global mean.
Adam Bourassa [University of Saskatchewan, Canada] introduced the satellite mission for High-altitude Aerosol, Water vapor, and Clouds (HAWC), planned as the Canadian contribution to the NASA Atmosphere Observing System (AOS) for launch in 2031 – a key component in NASA’s next generation Earth System Observatory. Bourassa highlighted the three Canadian instruments, which include limb profilers for water vapor and aerosol in the UTS and a far infrared imaging radiometer for ice cloud microphysics and radiative budget closure. He discussed instrument requirements and development progress as well as results from recent sub-orbital testing of prototypes on the NASA Earth Resources (ER)-2 and stratospheric balloons.
Trace Gases
Brian Soden [University of Miami] presented a new project that will use SAGE data to constrain climate sensitivity in climate models. Climate models differ substantially in their calculation of the radiative forcing from carbon dioxide (CO2), and these intermodel differences have remained largely unchanged for several decades. Soden highlighted the role of stratospheric temperature in modulating the radiative forcing from CO2. He explained that models that simulate a cooler stratosphere simulate a larger radiative forcing for the same change in CO2 compared to models that posit a warmer stratosphere. He added that determining the cause of the model biases in stratospheric temperature – particularly the role of water vapor in driving this intermodel spread – is an area of active research.
Ray Wang [Georgia Institute of Technology] compared the uncertainty analysis of SAGE III retrieved O3 and water vapor data in V5.3 to the same parameters in V6.0. He then compared the SAGE III data to the correlative measurements from other platforms. For O3, the differences between SAGE and measurements from the Microwave Limb Sounder (MLS) on NASA’s Aura platform are less than 5% in the stratosphere. SAGE V6.0 ozone values are systematically about 1–2% higher than those from V5.3 O3 – due to changes in how the O3 cross-section is represented in each version. For water vapor, SAGE data agree with MLS and Frost Point Hygrometer (FPH) data within 5%. Wang showed some differences between SAGE water vapor data retrievals using V5.3 and the same data obtained using version 6.0. He also said that a two-dimensional (i.e., spatial and temporal) regression model can be used to minimize sampling bias in climatology derived from non-uniform satellite measurements – ensuring more accurate representation of long-term trends.
Emma Knowland [GSFC/Morgan State University, Goddard Earth Sciences Technology and Research II (GESTAR II), now NASA HQ—SAGE III/ISS Program Scientist] discussed the progress of assimilating SAGE III water vapor data product into NASA’s GEOS re-analysis. Her team’s work demonstrated that while the number of solar occultation observations a day from SAGE III/ISS is about 1% of the total number of profiles observed globally by MLS, the chemical timescales of water vapor in the lower stratosphere are long enough that the SAGE III/ISS data can provide a valuable constraint on GEOS re-analysis, especially in the absence of MLS data – see Figure 4.
Figure 4. Hovmöller diagrams of the vertical distribution of 15°S–15°N average water vapor anomalies in upper troposphere–stratosphere with water vapor relaxed to a climatology [top left] and from data assimilation of SAGE III/ISS water vapor into the Goddard Earth Observing System (GEOS) model [bottom left]. Scatter plots show water vapor mixing ratios (y-axis) with [top right] and without [bottom right] data assimilation compared independent observations from the Atmospheric Chemistry Experiment – Fourier Transform Spectrometer (ACE-FTS) data (x-axis). The ACE–FTS data were not used in data assimilation. This shows that data assimilation of SAGE data improves the agreement with ACE-FTS – especially in the lower stratosphere (400 to 500 K). Figure Credit: Emma Knowland [NASA] Melody Avery [University of Colorado, Boulder] discussed using SAGE data and data from the Cloud–Aerosol Lidar with Orthogonal Projection (CALIOP) instrument (on the former Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) mission) to study thin clouds and aerosol distributions in the tropical tropopause region (TTL). Avery explained that these distributions from V5.3 of SAGE-III/ISS and V5.41 of CALIOP are shown to agree well, and CALIOP observations of cloud frequency are shown to be a sensitive metric for defining the width of the Hadley Cell near the tropical tropopause. Combining SAGE and CALIOP data produced a longer timescale to constrain and evaluate climate models that currently do not agree on how the tropical width at this altitude varies. They found that results derived using SAGE V6.0 versus V5.3 differ on the order of 2% in the TTL region.
Pamela Wales [GESTAR II] introduced a new project that leverages SAGE III/ISS measurements to explore diurnal characteristics of O3 and nitrogen dioxide (NO2) in GEOS model products. Her team is exploring potentially using a GEOS reanalysis of stratospheric trace gases collected by MLS as a transfer standard to evaluate the consistency between the SAGE III/ISS solar and the less frequently measured lunar retrieval. They are also assessing uncertainties in stratospheric NO2 in the GEOS Composition Forecast (GEOS-CF) model using SAGE III/ISS and complementary satellite instruments. This work will inform how effectively GEOS-CF can be used in air quality studies to remove the stratospheric signal from column retrievals of NO2.
Luis Millán [JPL] presented work on the change of stratospheric water vapor mass after the Hunga Tonga–Hunga Haʻapai (Hunga) volcano eruption in 2022. Millán found an increase (~10%) of total stratospheric water vapor – a potent greenhouse gas. Given their advanced age, MLS, ACE-FTS, and the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on NASA’s Thermosphere, Ionosphere, Mesosphere, Energetics and Dynamics (TIMED) mission (Heliosphere Division), are nearing the end of their missions, leaving SAGE III/ISS as the primary instrument for monitoring the plume’s evolution. Millán discussed how the SAGE III/ISS measurements might be sufficient to observe the dispersion of the excess Hunga water vapor from stratosphere in coming years. He also discussed a 39-year plus record of stratospheric water vapor mass using the overlapping periods between SAGE II, MLS, and SAGE III/ISS.
Ryan Stauffer [GSFC] presented the operation and outcomes of the Ticosonde balloon-borne O3 and water vapor sonde project in San Jose, Costa Rica. Ongoing since July 2005, Ticosonde has collected over 700 O3 profiles and 270 water vapor profiles for climate and pollution studies and satellite validation. Because Ticosonde is the only long-term water vapor sonde station in the tropics, the stratospheric water vapor data is vital for validation of SAGE-III/ISS and MLS profiles. Ticosonde has been used to verify the success of updated water vapor retrieval algorithms for both instruments – which now agree within a few percent up to 25 km (15 mi) altitude.
Natalya Kramarova [GSFC] showed the comparison of O3 profile retrieved from SAGE III with those derived from the OMPS-LP sensor – which is part of OMPS on NOAA-21 – from February 2023–June 2024. Diurnal corrections using the Goddard Diurnal Ozone Climatology (which is described in a 2020 article in Atmospheric Measurement Techniques) is applied to account for differences in measurement times between SAGE III’s sunrise or sunset observations and NOAA-21 LP’s midday measurements. Once the time correction is made, results show good agreement between the two instruments in depicting vertical ozone distribution across different geographical regions (e.g., tropics and mid-latitudes) and under various conditions (e.g., near the edge of the Antarctic O3 hole in October 2023). The mean biases between NOAA-21 LP and SAGE III are typically within ±5% between ~18–45 km (11–28 mi).
Project Team and Operations Highlights
Michael Heitz [LaRC] showed that V5.3 and previous versions of the SAGE III/ISS data product had a noticeable – and unphysical – dip in the retrieved aerosol extinction between 520–676 nm. This dip has been referred to as the aerosol “seagull.” However, adoption of a new absorption cross-section database into the V6.0 algorithm reduced the aerosol seagull effect significantly. Kevin Leavor [LaRC] presented new developments for the SAGE III/ISS quick look website. Mary Cate McKee [LaRC] introduced a new feature of the quick look website that showcases comparisons of O3 and water vapor sonde data at over 40 stations. Sonde data is sourced from the Network for the Detection of Atmospheric Composition Change (NDACC), GSFC’s SHADOZ, and the World Ozone and Ultraviolet Radiation Data Centre (WOUDC). Heitz explained that the comparison plots are updated continuously as new coincidences occur, providing the community with valuable insight to the quality of SAGE III/ISS data relative to this external network of ground stations. Future additions to the website include aerosol and lidar comparisons, additional plot statistics, and comparisons with novel homogenized datasets.
Returning to a topic discussed in Jamie Nehrir’s presentation, Charles Hill [LaRC] showed that the SAGE III Disturbance Monitoring Package (DMP) correction to the data product – which was implemented beginning with V5.3 – has significantly reduced the product uncertainties caused by ISS vibrations. Approximately 7% of SAGE III occultation events are highly disturbed by mechanical vibrations, and the DMP correction has improved pointing registrations in these events significantly. The DMP’s x-axis gyroscope failed on August 8, 2023 – but this loss did not significantly affect the DMP correction to scan plane elevation. Future possible losses of either the y- or z-axes will end active correction of ISS disturbances.
Conclusion
Jun Wang, David Flittner, and Richard Eckman led the closing discussion that highlighted the growing interest in atmospheric composition change – particularly due to emissions from large wildfires and volcanic eruptions in recent years. This increasing interest contrasts with the declining availability of observational data from the upper troposphere, following the retirement of CALIPSO in late 2023 and the planned decommissioning of Aura’s aging limb instruments in 2026. This gap underscores the critical importance of SAGE III/ISS data – not only for current UTS research but also for the next 5–7 years, during which no new limb measurements are planned.
SAGE III/ISS remains essential for profiling key atmospheric constituents, including water vapor, aerosols, O₃, and NO₂. The long-term, consistent data record provided by the SAGE series of instruments since the late 1970s – including SAGE III/ISS since 2017 – has been invaluable for studying past and future changes in atmospheric composition within the UTS. To further support research and applications of SAGE data products, participants discussed the possibility of proposing a special collection of articles in AGU journals.
Overall, the 2024 SAGE III/ISS meeting was a success. Participants received valuable updates on the status of SAGE III/ISS operations, data product calibration and validation, and new developments. The meeting also showcased the collective expertise and excellence in driving advancements in UTS research, from climate change studies to data assimilation for chemistry transport models and contributions to multi-sensor data fusion.
Jun Wang
University of Iowa
jun-wang-1@uiowa.edu
David Flittner
Langley Research Center
david.e.flittner@nasa.gov
Richard Eckman
NASA Langley Research Center
richard.s.eckman@nasa.gov
Emma Knowland
NASA Headquarters
k.e.knowland@nasa.gov
Share
Details
Last Updated May 26, 2025 Related Terms
Earth Science View the full article
-
By NASA
Explore This Section Earth Earth Observer Editor’s Corner Feature Articles Meeting Summaries News Science in the News Calendars In Memoriam More Archives Conference Schedules Style Guide 2 min read
2025 EGU Hyperwall Schedule
EGU General Assembly, April 27 – May 2, 2025
Join NASA in the Exhibit Hall (Booth #204) for Hyperwall Storytelling by NASA experts. Full Hyperwall Agenda below.
MONDAY, APRIL 28
10:15 – 10:30 AM —— PACE —— Ivona Cetinic 3:45 – 4:00 PM —— Science Explorer (SciX): Accelerating the Discovery of NASA Science —— Mike Kurtz 4:00 – 4:15 PM —— Juno’s Extended Vision in its Extended Mission —— Glenn Orton 6:05 – 6:20 PM —— Getting the Big Picture with Global Precipitation —— George Huffman 6:20 – 6:35 PM —— Exploring Europa with Europa Clipper —— Jonathan Lunine TUESDAY, APRIL 29
10:15 – 10:30 AM —— Science Explorer (SciX): Accelerating the Discovery of NASA Science —— Jennifer Lynn Bartlett 10:30 – 10:45 AM —— From ESTO to PACE, A CubeSat’s Journey to Space —— Brent McBride 12:30 – 2:00 PM —— Ask Me Anything with NASA Scientists —— Informal Office Hours 3:45 – 4:00 PM —— Exoplanets (Virtual) —— Jonathan H. Jiang 4:00 – 4:15 PM —— Scattering of Realistic Hydrometeors for Precipitation Remote Sensing ——Kwo-Sen Kuo 6:05 – 6:20 PM —— Space Weather Center of Excellence CLEAR: All-CLEAR SEP Forecast —— Lulu Zhao WEDNESDAY, APRIL 30
10:15 – 10:30 AM —— SPEXone on PACE: First year in Orbit —— Otto Hasekamp 12:30 – 2:00 PM —— Ask Me Anything with NASA Scientists —— Informal Office Hours 3:45 – 4:00 PM —— Science Explorer (SciX): Accelerating the Discovery of NASA Science —— Jennifer Lynn Bartlett 4:00 – 4:15 PM —— Scattering of Realistic Hydrometeors for Precipitation Remote Sensing ——Kwo-Sen Kuo 6:05 – 6:20 PM —— Ship Tracks Tell the Story of Climate Forcing by Aerosols through Clouds —Tianle Yuan 6:20 – 6:35 PM —— The Excitement of Mars Exploration —— Jonathan Lunine 6:35 – 6:50 PM —— Using NASA Earth Observations for Disaster Response —— Kristen Okorn THURSDAY, MAY 1
10:15 – 10:30 AM —— Getting the Big Picture with Global Precipitation —— George Huffman 3:45 – 4:00 PM —— PACE —— Morgaine McKibben 4:00 – 4:15 PM —— Using AI to Model Global Clouds Better Than Current GCRMs —— Tianle Yuan 6:05 – 6:20 PM —— Science Explorer (SciX): Accelerating the Discovery of NASA Science —— Mike Kurtz Share
Details
Last Updated Apr 24, 2025 Related Terms
Earth Science 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.