Launched in February 2024, NASA’s Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission stands as a pivotal initiative in Earth system science, aiming to unravel the complex interactions between environmental and biological components that impact climate, carbon cycles, and ecosystems. The mission has been bolstered by three key components: the PACE Postlaunch Airborne eXperiment (PACE-PAX), the third PACE Science and Applications Team (SAT3), and the PACE Validation Science Team (PVST). Each plays a crucial role in advancing the mission’s scientific goals through product development and meticulous data quality assessment.
This year, recognizing the interconnected nature of these groups, organizers combined their separate meetings into a comprehensive event known as the “PAC3” meeting. Held from February 18-21, 2025, at NASA’s Goddard Institute for Space Studies (GISS) in New York City, the gathering occurred just ten days after PACE’s first anniversary.
The PACE Mission and Its Instruments
PACE’s objectives include understanding ocean and terrestrial ecosystem productivity, detecting harmful algal blooms, exploring aerosol-cloud interactions, and integrating these insights into broader Earth system science. The mission employs a suite of three advanced instruments to achieve these goals.
The Ocean Color Instrument (OCI) is a hyperspectral radiometer that captures light over hundreds of narrow wavelengths, providing insights into ocean ecosystems and atmospheric components. The Hyper-Angular Rainbow Polarimeter #2 (HARP2) and the Spectropolarimeter for Planetary Exploration (SPEXone) are multiangle polarimeters designed to retrieve aerosol and cloud properties, each with unique capabilities that complement the other.
PACE Mission Updates and Instrument Performance
During the PAC3 meeting, updates on the PACE mission’s status and developments were provided by the instrument scientists. Gerhard Meister from NASA’s Goddard Space Flight Center reported that OCI has exceeded radiometric performance requirements, delivering highly accurate hyperspectral data. Key improvements include enhanced atmospheric corrections and updated calibration parameters.
Otto Hasekamp from the Space Research Organization in the Netherlands highlighted SPEXone’s delivery of quality radiometric and polarimetric data. The team has developed the RemoTAP algorithm, which offers advanced aerosol retrieval capabilities. Meanwhile, Vanderlei Martins from the University of Maryland, Baltimore County, noted HARP2’s continued success in providing polarization-sensitive observations of aerosols and clouds.
Data Access and Collaborative Efforts
Alicia Scott from NASA’s Goddard Space Flight Center detailed the capabilities of the Ocean Biology Distributed Active Archive Center (OB.DAAC), which processes and stores data from all PACE instruments. Carina Poulin provided an overview of the PACE Data Website, a central hub for accessing datasets and integrating PACE data into user workflows.
The PAC3 meeting also included participation from the Earth Clouds, Aerosols, and Radiation Explorer (EarthCARE) mission teams, a joint venture by the European Space Agency and the Japan Aerospace Exploration Agency. Rob Koopman from ESA reported on EarthCARE’s progress, emphasizing the synergy between the two missions in advancing scientific knowledge of Earth system processes.
PACE-PAX and Validation Campaigns
The PACE-PAX field campaign, conducted in California and adjacent coastal regions, played a critical role in validating PACE and EarthCARE products. Led by Kirk Knobelspiesse, Ivona Cetinić, and Brian Cairns, the campaign involved a diverse array of platforms, including aircraft and research vessels, to collect atmospheric and oceanic data.
Preliminary findings from the PACE-PAX sessions demonstrated successful validation of aerosol and cloud products, as well as observations of diverse phenomena such as marine stratocumulus clouds and wildfire aerosols. These efforts underscore the importance of validation activities in bridging orbital science with ground truth.
Science and Application Team (SAT3) Insights
The SAT3 team focused on how PACE data can enhance research across various scientific fields and support societal applications. Presentations highlighted efforts to develop predictive models for harmful algal blooms and improve early warning systems. The discussions underscored PACE’s potential to impact disciplines ranging from oceanography to climate science.
Conclusion
The PAC3 meeting at NASA’s GISS showcased the collaborative efforts of the PACE mission’s diverse teams in addressing Earth system science challenges. By combining the meetings for PACE-PAX, SAT3, and PVST, participants strengthened collaborations, aligned ongoing efforts, and laid the groundwork for future research and validation activities. As PACE continues to deliver valuable data, its role in enhancing our understanding of Earth’s complex systems remains pivotal.
