Uncertainty in Aerosol–Cloud Radiative Forcing Is Driven By Clean Conditions

• Published in: Atmospheric chemistry and physics Vol. 23; no. 7; pp. 4115 - 4122
• Main Authors: Gryspeerdt, Edward, Povey, Adam C., Grainger, Roy G., Hasekamp, Otto, Hsu, N. Christina, Mulcahy, Jane P., Sayer, Andrew M., Sorooshian, Armin
• Format: Journal Article
• Language: English
• Published: 2230 Support European Geosciences Union/Copernicus Publications 05.04.2023; Copernicus GmbH; Copernicus Publications
• Subjects: Aerosol effects; Aerosol-cloud interactions; Aerosols; Analysis; Atmospheric aerosols; Atmospheric models; Atmospheric physics; Climate; Climate models; Climate system; Cloud droplet concentration; Cloud droplet size; Cloud droplets; Cloud properties; Clouds; Droplets; Estimates; Geosciences (General); Global climate; Global climate models; Observational studies; Optical properties; Proxies; Radiative forcing; Reflectance; Satellites; Uncertainty
• ISSN: 1680-7316; 1680-7324; 1680-7324
• DOI: 10.5194/acp-23-4115-2023

Atmospheric aerosols and their impact on cloud properties remain the largest uncertainty in the human forcing of the climate system. By increasing the concentration of cloud droplets (Nd), aerosols reduce droplet size and increase the reflectivity of clouds (a negative radiative forcing). Central to this climate impact is the susceptibility of cloud droplet number to aerosol (β), the diversity of which explains much of the variation in the radiative forcing from aerosol–cloud interactions (RFaci) in global climate models. This has made measuring β a key target for developing observational constraints of the aerosol forcing.