Introduction
In a significant gathering of minds within the scientific community, the Stratospheric Aerosol and Gas Experiment III (SAGE III) team, alongside members from the International Space Station (ISS), convened for a Science Team Meeting (STM) on October 22–23, 2024. This hybrid event was hosted at NASA’s Langley Research Center (LaRC), drawing in approximately 50 scientists from various esteemed institutions, including U.S. universities, NASA’s Goddard Space Flight Center (GSFC), the Jet Propulsion Laboratory (JPL), and the National Oceanic and Atmospheric Administration (NOAA). Additionally, the meeting featured insights from international experts based in Canada and Germany.
The SAGE missions, renowned for their contributions to atmospheric science, have been pivotal in enhancing our understanding of the Earth’s atmospheric composition. The SAGE III/ISS mission specifically aims to provide critical data on aerosols and gases in the stratosphere, thus playing a vital role in climate studies and environmental monitoring. This article delves into the details of the 2024 STM, highlighting the key outcomes and future prospects discussed during this pivotal meeting. For those interested in a comprehensive look at the agenda and presentations, they can be accessed through the SAGE III/ISS website.
Day One
The meeting commenced with a warm welcome from Jun Wang, the SAGE III/ISS Science Team Leader from the University of Iowa, and David Flittner, the Project Scientist from LaRC. They were joined by Richard Eckman, the SAGE III/ISS Program Scientist from NASA Headquarters, who shared his opening remarks. The logistics of the meeting were then outlined by Allison McMahon, the Communications Lead from LaRC/Science Systems and Applications, Inc. (SSAI).
The first day was structured to provide an overview of the current status and future endeavors of the SAGE III/ISS mission. The morning sessions concentrated on project updates and explored the synergistic potential between SAGE III/ISS and upcoming missions slated for the early 2030s. The afternoon was dedicated to discussions on aerosol research and the calibration and validation of SAGE III/ISS data products.
Project Operation and Data Product Briefing
David Flittner presented a comprehensive update on the mission’s status, highlighting over seven years of continuous data collection and analysis. The mission recently underwent the 2023 Earth Science Senior Review, and its proposal for continued operations through 2026 was approved by NASA Headquarters, albeit with some budgetary constraints. This approval ensures the mission can maintain its community validation efforts, including the development of online tools for quick data analysis and timely improvements to algorithms and products. Despite some necessary staff reductions, Flittner described 2024 as a year of growth for the SAGE III/ISS team, with several key activities planned for the new Science Team cohort.
Robbie Manion from LaRC introduced version 6.0 (V6) of the SAGE III/ISS data products, released in April 2025. This new version addresses previous biases in aerosol extinction measurements and allows for the recovery of numerous profiles hindered by sunspots. Jamie Nehrir reported on the payload’s performance, noting its successful acquisition of over 70,000 occultation events. Despite some degradation in the Disturbance Monitoring Package’s lasers, the team continues to engage with partners to assess any potential impacts on data quality.
Synergy with New Limb Missions
The meeting also featured presentations on emerging missions that could complement SAGE III/ISS’s work. Lyatt Jaeglé from the University of Washington introduced the Stratosphere Troposphere Response using Infrared Vertically-resolved light Explorer (STRIVE), a mission concept selected for a competitive study within NASA’s Earth System Explorers Program. STRIVE aims to provide high-resolution profiles of atmospheric components, filling a critical gap in current observational capabilities.
Similarly, Björn-Martin Sinnhuber from the Karlsruhe Institute of Technology in Germany discussed the Changing-Atmosphere Infrared Tomography Explorer (CAIRT), a candidate mission for the European Space Agency’s Earth Explorer 11 satellite. If selected, CAIRT would offer valuable insights into atmospheric dynamics and composition from the upper troposphere to the lower thermosphere.
Aerosols and Related Research
Mahesh Mundakkara presented research on the Global Space-based Stratospheric Aerosol Climatology (GloSSAC) product, which is essential for understanding the climatic effects of stratospheric aerosols. The presentation emphasized the evaluation of the Ozone Mapping and Profiler Suite (OMPS) limb profiler data against other datasets, including SAGE III/ISS, to ensure its integration into GloSSAC.
Jianglong Zhang discussed a new SAGE project aimed at enhancing stratospheric aerosol analyses for future climate applications. Preliminary comparisons of SAGE aerosol extinction data with that from the Cloud Aerosol Transport System (CATS) lidar were also presented. Sara Lu focused on examining smoke aerosol radiative effects in the upper troposphere and lower stratosphere using SAGE III/ISS observations.
Xi Chen and Jun Wang introduced a project utilizing SAGE III/ISS lunar measurements to retrieve aerosol properties. The team is developing a normalization method to address challenges posed by the Moon’s non-uniform surface, with promising preliminary results.
Advanced Modeling and New Satellite Missions
The second day of the meeting began with Jack Kaye from NASA Earth Science Division sharing a historical perspective on SAGE and its role within NASA’s Earth science program. This was followed by technical sessions featuring presentations on advanced modeling and new satellite missions for studying the upper troposphere and lower stratosphere (UTS).
Steven Pawson from GSFC highlighted the capabilities of the Goddard Earth Observing System (GEOS) model in analyzing UTS dynamics and composition. The presentation detailed recent support for the Asian summer monsoon Chemical and Climate Impact Project (ACCLIP) mission and plans for future improvements in the GEOS model.
Kostas Tsigaridis from Columbia University discussed the climate impacts of increased launches to Low Earth Orbit (LEO), focusing on emissions inventories and their potential effects on climate predictions. Adam Bourassa introduced the High-altitude Aerosol, Water vapor, and Clouds (HAWC) satellite mission, part of NASA’s Atmosphere Observing System, slated for launch in 2031.
Trace Gases and Related Studies
Brian Soden from the University of Miami presented a project using SAGE data to refine climate sensitivity in models. His research underscores the role of stratospheric temperature in modulating radiative forcing from carbon dioxide. Ray Wang from Georgia Institute of Technology compared SAGE III data with other platforms, highlighting improvements in the latest data version (V6.0).
Emma Knowland from GSFC/Morgan State University discussed progress in assimilating SAGE III water vapor data into NASA’s GEOS re-analysis. The SAGE data, despite being a fraction of the total global observations, provide valuable constraints on re-analysis, especially when other data sources are unavailable.
Conclusion
The 2024 SAGE III/ISS meeting concluded with a discussion led by Jun Wang, David Flittner, and Richard Eckman. They emphasized the growing interest in atmospheric composition changes due to recent large-scale emissions from wildfires and volcanic eruptions. This interest contrasts with the declining availability of observational data, underscoring the essential role of SAGE III/ISS in filling this gap.
The meeting was deemed a success, providing valuable updates on SAGE III/ISS operations, data product calibration, and validation. It also highlighted the collective expertise driving advancements in UTS research, from climate change studies to data assimilation and multi-sensor data fusion. Overall, the SAGE III/ISS mission remains a cornerstone for atmospheric research, offering critical insights into the Earth’s atmospheric dynamics and composition.
For more Information, Refer to this article.
