EGU2020-5864
https://doi.org/10.5194/egusphere-egu2020-5864
EGU General Assembly 2020
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Impacts of Ice Cloud Particle Size Uncertainty on Radiation, and Precipitation and Climate Sensitivity and the Significance of Future Satellite-Based Constraints

Hui Su, Yuan Wang, Jonathan Jiang, Feng Xu, and Yuk Yung
Hui Su et al.
  • California Institute of Technology, Jet Propulsion Laboratory, Pasadena, United States of America (hui.su@jpl.nasa.gov)

Ice cloud particle size is important to determining ice cloud radiative effect and precipitating rate. However, there is a lack of accurate ice particle effective radius (Rei) observation on the global scale and the parameterization of Rei in climate models is poorly constrained. We conduct a modeling study to assess the sensitivity of climate simulations to Rei. Perturbations to Rei are represented in ice fall speed parameterization and radiation scheme, respectively, in NCAR CESM1 model with a slab ocean configuration. We show that an increase in ice fall speed due to a larger Rei results in a longwave cooling dominating over a shortwave warming, a global mean surface temperature decrease, and precipitation suppression. Similar longwave and shortwave cloud radiative effect changes occur when Rei is perturbed in the radiation scheme. Perturbing falling snow particle size (Res) results in much smaller changes in the climate responses. We further show that varying Rei and Res by 50% to 200% relative to the control experiment can cause climate sensitivity to differ by +12.3% to −6.2%. A future mission under design with combined multi-frequency microwave radiometers and cloud radar can reduce the uncertainty ranges of Rei and Res from a factor of 2 to ±25%, which would help reducing the climate sensitivity uncertainty pertaining to ice cloud particle size by approximately 60%.

 

How to cite: Su, H., Wang, Y., Jiang, J., Xu, F., and Yung, Y.: Impacts of Ice Cloud Particle Size Uncertainty on Radiation, and Precipitation and Climate Sensitivity and the Significance of Future Satellite-Based Constraints , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5864, https://doi.org/10.5194/egusphere-egu2020-5864, 2020.

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