Cloud-aerosol interactions in subtropical marine stratocumulus weaken in a warmer climate

Fuente: arXiv
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Auteurs principaux: Sun, Hongwei, Blossey, Peter, Wood, Robert, Erfani, Ehsan, Doherty, Sarah, Chun, Je-Yun
Format: Preprint
Publié: 2025
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author Sun, Hongwei
Blossey, Peter
Wood, Robert
Erfani, Ehsan
Doherty, Sarah
Chun, Je-Yun
author_facet Sun, Hongwei
Blossey, Peter
Wood, Robert
Erfani, Ehsan
Doherty, Sarah
Chun, Je-Yun
contents Radiative effects of aerosol-cloud interactions constitute the most uncertain climate forcing of the Earth system, making it important to understand how they may change with climate. We conduct 3-day-long large-eddy simulations of a stratocumulus-to-cumulus transition along an airmass-following trajectory over the Northeast Pacific Ocean. By perturbing boundary layer aerosol concentrations, we simulate aerosol-cloud interactions in both present-day and doubled-CO2 conditions. Aerosol-induced cloud changes, including the Twomey effect and adjustments of cloud fraction and liquid water path, are inhibited in a doubled-CO2 climate. Decomposing the aerosol-induced cloud radiative effect change ($Δ$CRE) reveals that aerosol-induced cloud fraction changes dominate $Δ$CRE. Overall, doubling CO2 attenuates aerosol-induced $Δ$CRE (i.e., cooling) by >30% in our simulations. Our results also show that low cloud feedbacks are sensitive to the background aerosol concentration, highlighting the interplay between climate forcings and feedbacks. These results may aid in predicting the cooling potential of marine cloud brightening in a changing climate.
format Preprint
id arxiv_https___arxiv_org_abs_2507_01319
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Cloud-aerosol interactions in subtropical marine stratocumulus weaken in a warmer climate
Sun, Hongwei
Blossey, Peter
Wood, Robert
Erfani, Ehsan
Doherty, Sarah
Chun, Je-Yun
Atmospheric and Oceanic Physics
Radiative effects of aerosol-cloud interactions constitute the most uncertain climate forcing of the Earth system, making it important to understand how they may change with climate. We conduct 3-day-long large-eddy simulations of a stratocumulus-to-cumulus transition along an airmass-following trajectory over the Northeast Pacific Ocean. By perturbing boundary layer aerosol concentrations, we simulate aerosol-cloud interactions in both present-day and doubled-CO2 conditions. Aerosol-induced cloud changes, including the Twomey effect and adjustments of cloud fraction and liquid water path, are inhibited in a doubled-CO2 climate. Decomposing the aerosol-induced cloud radiative effect change ($Δ$CRE) reveals that aerosol-induced cloud fraction changes dominate $Δ$CRE. Overall, doubling CO2 attenuates aerosol-induced $Δ$CRE (i.e., cooling) by >30% in our simulations. Our results also show that low cloud feedbacks are sensitive to the background aerosol concentration, highlighting the interplay between climate forcings and feedbacks. These results may aid in predicting the cooling potential of marine cloud brightening in a changing climate.
title Cloud-aerosol interactions in subtropical marine stratocumulus weaken in a warmer climate
topic Atmospheric and Oceanic Physics
url https://arxiv.org/abs/2507.01319