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Modeling of the Wegener–Bergeron–Findeisen process—implications for aerosol indirect effects
A new parameterization of the Wegener–Bergeron–Findeisen (WBF) process has been developed, and implemented in the general circulation model CAM-Oslo. The new parameterization scheme has important implications for the process of phase transition in mixed-phase clouds. The new treatment of the WBF process replaces a previous formulation, in which the onset of the WBF effect depended on a threshold value of the mixing ratio of cloud ice. As no observational guidance for such a threshold value exists, the previous treatment added uncertainty to estimates of aerosol effects on mixed-phase clouds. The new scheme takes subgrid variability into account when simulating the WBF process, allowing for smoother phase transitions in mixed-phase clouds compared to the previous approach. The new parameterization yields a model state which gives reasonable agreement with observed quantities, allowing for calculations of aerosol effects on mixed-phase clouds involving a reduced number of tunable parameters. Furthermore, we find a significant sensitivity to perturbations in ice nuclei concentrations with the new parameterization, which leads to a reversal of the traditional cloud lifetime effect.
Modeling of the Wegener–Bergeron–Findeisen process—implications for aerosol indirect effects
A new parameterization of the Wegener–Bergeron–Findeisen (WBF) process has been developed, and implemented in the general circulation model CAM-Oslo. The new parameterization scheme has important implications for the process of phase transition in mixed-phase clouds. The new treatment of the WBF process replaces a previous formulation, in which the onset of the WBF effect depended on a threshold value of the mixing ratio of cloud ice. As no observational guidance for such a threshold value exists, the previous treatment added uncertainty to estimates of aerosol effects on mixed-phase clouds. The new scheme takes subgrid variability into account when simulating the WBF process, allowing for smoother phase transitions in mixed-phase clouds compared to the previous approach. The new parameterization yields a model state which gives reasonable agreement with observed quantities, allowing for calculations of aerosol effects on mixed-phase clouds involving a reduced number of tunable parameters. Furthermore, we find a significant sensitivity to perturbations in ice nuclei concentrations with the new parameterization, which leads to a reversal of the traditional cloud lifetime effect.
Modeling of the Wegener–Bergeron–Findeisen process—implications for aerosol indirect effects
Modeling of the Wegener–Bergeron–Findeisen process—implications for aerosol indirect effects
T Storelvmo (author) / J E Kristjánsson (author) / U Lohmann (author) / T Iversen (author) / A Kirkevåg (author) / Ø Seland (author)
Environmental Research Letters ; 3 ; 045001
2008-10-01
10 pages
Article (Journal)
Electronic Resource
English
Modeling of the Wegener–Bergeron–Findeisen process—implications for aerosol indirect effects
| IOP Institute of Physics | 2010
| Online Contents | 2012
| DeGruyter | 2012
Online Contents | 2006