The NASA ACTIVATE Mission

Abstract The NASA Aerosol Cloud Meteorology Interactions over the Western Atlantic Experiment (ACTIVATE) conducted 162 joint flights with two aircraft over the northwest Atlantic to study aerosol–cloud interactions (ACIs), which represent the largest uncertainty in estimating total anthropogenic radiative forcing. The combination of a high-flying King Air and low-flying HU-25 Falcon, equipped with remote sensing and in situ instruments, characterized trace gases, aerosol particles, clouds, and meteorological variables with data collected nearly simultaneously below, within, and above marine boundary layer (MBL) clouds. Flights spanning warm and cold seasons across 3 years (2020–22) provided a broad range of conditions associated with aerosol particles, cloud properties (including particle size and phase), and meteorology, ideally suited for robust ACI calculations and assessing how well models simulate a wide range of MBL clouds from stratiform to cumulus. ACTIVATE data suggest that drivers of cloud droplet number concentration N d , including aerosol particles and MBL dynamics, vary between winter and summer months with a stronger potential to convert aerosol particles into cloud droplets in winter. Models of varying complexity not only highlight some skills in simulating winter and summer cloud types but also identify challenges that still need to be addressed such as treatment of turbulence, wet scavenging, and mesoscale organization. Remote sensing advances range from new retrieval methods for N d , cloud phase classification, vertically resolved aerosol and cloud condensation nuclei number concentration, and ocean surface wind speed. This work describes these scientific and technological advances along with efforts in outreach and open data science. Significance Statement Depending on the number and type of aerosol particles there are in the air, the properties of cloud droplets can vary in number concentration, size, and lifetime, and this leads to varying effects of clouds on climate and weather. We took an ambitious approach to investigate aerosol–cloud interactions, which represent the largest uncertainty in estimating human impacts on climate change. The NASA ACTIVATE mission conducted 162 joint airborne flights over the northwest Atlantic with two spatially coordinated planes making measurements relevant to understanding clouds spanning the continuum from stratiform to cumulus clouds. Along with newfound knowledge of how clouds evolve and interact with aerosol particles, extensive technological advancements were made assisted by the carefully designed sampling strategy.

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Institutions

Publication Details

Journal
Bulletin of the American Meteorological Society
Published
2025-05-26
DOI
https://doi.org/10.1175/bams-d-24-0136.1
Citations
8
Primary Topic
Spacecraft Design and Technology
Type
article
Field-Weighted Citation Impact
39.95

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article

The NASA ACTIVATE Mission

Brian Cairns, Xubin Zeng, Snorre Stamnes, Hongyu Liu et al.
8 citations
Bulletin of the American Meteorological Society
Spacecraft Design and Technology
39.95
article

The NASA ACTIVATE Mission

Brian Cairns, Xubin Zeng, Snorre Stamnes, Hongyu Liu, Sam J. Silva, Paquita Zuidema, Mary M. Kleb, Holger Vömel, Seethala Chellappan, Bastiaan van Diedenhoven, Joseph S. Schlosser, Cassidy Soloff, Lauren Cutler, Kenneth Sinclair, Kelly M. Butler, Taylor Shingler, Michael A. Shook, Ewan Crosbie, Leong Wai Siu, Shuaiqi Tang, Soodabeh Namdari, Yike Xu, David Painemal, Joshua P. DiGangi, Armin Sorooshian, Christiane Voigt, Jingyi Chen, Glenn S. Diskin, C. A. Hostetler, Luke D. Ziemba, Edward L. Winstead, Hailong Wang, Johnathan W. Hair, Simon Kirschler, William L. Smith, Michael A. Brunke, Florian Tornow, George Tselioudis, R. A. Ferrare, Yonghoon Choi, Allison McComiskey, Xiangyu Li, Bo Zhang, Kenneth L. Thornhill
article en
8 citations

Abstract

Abstract The NASA Aerosol Cloud Meteorology Interactions over the Western Atlantic Experiment (ACTIVATE) conducted 162 joint flights with two aircraft over the northwest Atlantic to study aerosol–cloud interactions (ACIs), which represent the largest uncertainty in estimating total anthropogenic radiative forcing. The combination of a high-flying King Air and low-flying HU-25 Falcon, equipped with remote sensing and in situ instruments, characterized trace gases, aerosol particles, clouds, and meteorological variables with data collected nearly simultaneously below, within, and above marine boundary layer (MBL) clouds. Flights spanning warm and cold seasons across 3 years (2020–22) provided a broad range of conditions associated with aerosol particles, cloud properties (including particle size and phase), and meteorology, ideally suited for robust ACI calculations and assessing how well models simulate a wide range of MBL clouds from stratiform to cumulus. ACTIVATE data suggest that drivers of cloud droplet number concentration N d , including aerosol particles and MBL dynamics, vary between winter and summer months with a stronger potential to convert aerosol particles into cloud droplets in winter. Models of varying complexity not only highlight some skills in simulating winter and summer cloud types but also identify challenges that still need to be addressed such as treatment of turbulence, wet scavenging, and mesoscale organization. Remote sensing advances range from new retrieval methods for N d , cloud phase classification, vertically resolved aerosol and cloud condensation nuclei number concentration, and ocean surface wind speed. This work describes these scientific and technological advances along with efforts in outreach and open data science. Significance Statement Depending on the number and type of aerosol particles there are in the air, the properties of cloud droplets can vary in number concentration, size, and lifetime, and this leads to varying effects of clouds on climate and weather. We took an ambitious approach to investigate aerosol–cloud interactions, which represent the largest uncertainty in estimating human impacts on climate change. The NASA ACTIVATE mission conducted 162 joint airborne flights over the northwest Atlantic with two spatially coordinated planes making measurements relevant to understanding clouds spanning the continuum from stratiform to cumulus clouds. Along with newfound knowledge of how clouds evolve and interact with aerosol particles, extensive technological advancements were made assisted by the carefully designed sampling strategy.

Bulletin of the American Meteorological SocietyVol. 106(8)
NSF National Center for Atmospheric Research (US), Goddard Institute for Space Studies (US), University of Southern California (US), Statewide California Earthquake Center (US), Langley Research Center (US), National Institute of Aerospace (US), University of Arizona (US), Pacific Northwest National Laboratory (US), University of Miami (US), University of Applied Sciences Mainz (DE), Johannes Gutenberg University Mainz (DE), Nanjing University of Information Science and Technology (CN), Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR) (DE), Analytical Mechanics Associates (United States) (US), Space Research Organisation Netherlands (NL), Columbia University (US), Nanjing University (CN)
U.S. Department of Energy, National Aeronautics and Space Administration, Battelle, Oak Ridge Associated Universities, University of Miami, Deutsche Forschungsgemeinschaft, Nuclear Safety and Security Commission, Goddard Space Flight Center, Langley Research Center, Pacific Northwest National Laboratory
Openalex Percentile: Top 0%
Spacecraft Design and Technology
39.95
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