- 1Department of Meteorology, Stockholm University, Stockholm, Sweden
- 2Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden
- 3NOAA Geophysical Fluid Dynamics Laboratory, Princeton, NJ, USA
- 4Pacific Northwest National Laboratory, Richland, WA, USA
- 5Department of Geosciences, University of Oslo, Oslo, Norway
- 6National Center for Atmospheric Research, Boulder, CO, USA
- 7Department of Earth and Planetary Sciences, University of California, Berkeley, CA, USA
- 8Research Institute for Applied Mechanics, Kyushu University, Fukuoka, Japan
- 9Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA
- 10Graduate School of Business, Nord University, Bodø, Norway
Changes in cloud scattering properties and emissivity that arise from atmospheric warming cause substantial radiative feedbacks in model projections of anthropogenic climate change, and the relative importance of the underlying mechanisms is poorly understood. One leading hypothesis is that ice-to-liquid conversions cause clouds to optically thicken, producing a major negative feedback. We test this hypothesis by developing a method to decompose cloud radiative feedbacks by cloud-top phase. The method is applied to an ensemble of six state-of-the-art global climate models run with prescribed sea-surface temperature. In these simulations, the global mean of the net cloud scattering and emissivity feedback from cloud-phase conversions ranges from -0.17 to -0.01 W m-2 K-1, while the overall net cloud feedback ranges from 0.02 to 0.91 W m-2 K-1. The multi-model mean of the cloud scattering and emissivity feedback from cloud-phase conversions is approximately 18% of the magnitude of the multi-model mean of the overall cloud feedback (-0.10 W m-2 K-1 vs. 0.52 W m-2 K-1). These results indicate that cloud-phase conversions cause a robust negative feedback by changing cloud scattering and emissivity, but this mechanism makes a modest contribution to the overall cloud feedback at the global scale.
How to cite: Wall, C., Paynter, D., Qin, Y., Debolskiy, M., Duffy, M., Michibata, T., Duran, B., Lutsko, N., Ma, P.-L., Medeiros, B., Storelvmo, T., and Zhao, M.: Decomposing Cloud Radiative Feedbacks by Cloud-Top Phase, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8415, https://doi.org/10.5194/egusphere-egu25-8415, 2025.
