Coarse-mode sea spray aerosols enhance warm rain formation in marine low clouds
- 1University of Washington (Seattle, United States of America)
Abstract
Precipitation in low clouds affects cloud responses to aerosol perturbations, thereby impacting aerosol radiative forcing of climate, a significant but indeterminate contribution to uncertainty in future warming. The onset of drizzle formation in marine low clouds may be influenced by the presence of supermicron sea salt aerosols. These particles can act as giant CCN (GCCN) that benefit from rapid condensational growth to a size that initiates collision-coalescence. Aircraft-based in-situ observations of cloud microphysical properties and aerosol size distributions from the Aerosol Cloud meTeorology Interactions oVer the western ATlantic Experiment (ACTIVATE) are analyzed from January–June 2022. Observations from a cloud aerosol spectrometer and a cloud droplet probe in clear air are used to quantify GCCN size distributions. Modest correlations are found between GCCN and near surface-level wind speeds when averaged together into wind speed bins, a result consistent with other studies. Observed GCCN distributions and cloud thicknesses are used to drive simulations within a 1-dimensional kinematic super droplet model, exploring the conditions under which the observed GCCN distributions induce a first-order impact on precipitation rate. The model demonstrates that even relatively small GCCN salt masses (∼ 1 µg m ⁻³ ) can accelerate the onset of drizzle in lightly precipitating marine low clouds. Similarly, a statistical analysis of in-cloud data shows the ratio of rainwater to total condensed water is higher when GCCN concentration/mass is above average. Together, the results indicate a significant influence of GCCN on precipitation formation in marine low clouds.
Versions
Related
- Comparative nitrogen speciation in marine and coastal urban aerosols of the Greater Bay Area and implications for PM2.5-bound nitrogen deposition
- In-cloud motions shape warm-rain production in marine clouds: Evidence from multiyear observations
- Linking molecular composition of organic aerosols to reactive oxygen species formation using an MCR-VK framework
- New Insights Into Nighttime Marine Sulfur and Nitrogen Chemistry and Related New Particle Formation Using the CLEPS Model
- Interacting effects of droplet number and ice formation processes on mixed-phase cold-air outbreak clouds
BibTeX
@article{mifsud2026coarsemode,
title = {{Coarse-mode sea spray aerosols enhance warm rain formation in marine low clouds}},
author = {Katherine Mifsud and Jason Barr and Robert Wood and Yonghoon Choi and Ewan Crosbie and Glenn S. Diskin and Joshua P. DiGangi and Richard H. Moore and Claire Robinson and Michael A. Shook and Armin Sorooshian and Christiane Voigt and Luke Ziemba},
journal = {Atmospheric Chemistry and Physics},
year = {2026},
month = oct,
doi = {10.5194/acp-26-14881-2026},
url = {https://acp.copernicus.org/articles/26/14881/2026/},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Coarse-mode sea spray aerosols enhance warm rain formation in marine low clouds
AU - Katherine Mifsud
AU - Jason Barr
AU - Robert Wood
AU - Yonghoon Choi
AU - Ewan Crosbie
AU - Glenn S. Diskin
AU - Joshua P. DiGangi
AU - Richard H. Moore
AU - Claire Robinson
AU - Michael A. Shook
AU - Armin Sorooshian
AU - Christiane Voigt
AU - Luke Ziemba
PY - 2026
DA - 2026/10/23
JO - Atmospheric Chemistry and Physics
DO - 10.5194/acp-26-14881-2026
UR - https://acp.copernicus.org/articles/26/14881/2026/
AB - Precipitation in low clouds affects cloud responses to aerosol perturbations, thereby impacting aerosol radiative forcing of climate, a significant but indeterminate contribution to uncertainty in future warming. The onset of drizzle formation in marine low clouds may be influenced by the presence of supermicron sea salt aerosols. These particles can act as giant CCN (GCCN) that benefit from rapid condensational growth to a size that initiates collision-coalescence. Aircraft-based in-situ observations of cloud microphysical properties and aerosol size distributions from the Aerosol Cloud meTeorology Interactions oVer the western ATlantic Experiment (ACTIVATE) are analyzed from January–June 2022. Observations from a cloud aerosol spectrometer and a cloud droplet probe in clear air are used to quantify GCCN size distributions. Modest correlations are found between GCCN and near surface-level wind speeds when averaged together into wind speed bins, a result consistent with other studies. Observed GCCN distributions and cloud thicknesses are used to drive simulations within a 1-dimensional kinematic super droplet model, exploring the conditions under which the observed GCCN distributions induce a first-order impact on precipitation rate. The model demonstrates that even relatively small GCCN salt masses (∼ 1 µg m ⁻³ ) can accelerate the onset of drizzle in lightly precipitating marine low clouds. Similarly, a statistical analysis of in-cloud data shows the ratio of rainwater to total condensed water is higher when GCCN concentration/mass is above average. Together, the results indicate a significant influence of GCCN on precipitation formation in marine low clouds.
SN - 1680-7324
SN - 1680-7316
ER -