Sensitivity Tests of the P3 Microphysical Scheme: Modifying Ice Fall Speeds in CM1
Dengate, J., Takeishi, A., Rosky, E.. (2025). Sensitivity Tests of the P3 Microphysical Scheme: Modifying Ice Fall Speeds in CM1. , doi:https://doi.org/10.5065/fppm-1g21
| Title | Sensitivity Tests of the P3 Microphysical Scheme: Modifying Ice Fall Speeds in CM1 |
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| Genre | Manuscript |
| Author(s) | Jacob Dengate, Azusa Takeishi, Elise Rosky |
| Abstract | Microphysical schemes within atmospheric models quantify the properties and dynamics of cloud systems, and the parametrization of these schemes heavily affect the output of these models. The Predicted Particle Properties (P3) scheme is a relatively new microphysical scheme that, unlike other schemes, allows ice particle densities to vary with space and time. Despite the P3 scheme's complex modeling of ice particles in comparison to other schemes, its parametrization of atmospheric processes and properties can be further improved by conducting sensitivity tests of uncertain parameters. In this study, the fall speed of ice particles in a tropical environment will be modified using multiplicative factors as a proxy for changes in the density, orientation, and shape of ice particles such as hail, which are sources of uncertainty in the P3 parameterization. This is done in order to study how the cloud structure and precipitation in the model output is affected by these changes. The results of this study show that with a decrease in fall speed, there is significantly less precipitation overall without a notable change in hail characteristics. Additionally, in simulations with lower fall speeds, clouds contained a higher ice content in the upper levels compared to the unmodified control run due to the ice having the inability to penetrate through the updraft and melting layer. Future works may explore this effect within different storm environments, or with different microphysical schemes. The key takeaway is that the P3 microphysical scheme represents the upper-bound of surface rainfall from the supercell storm simulated in this study. This finding may be applicable to other convective storms, although this will need to be confirmed by further studies. |
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| Publication Date | Aug 1, 2025 |
| Publisher's Version of Record | https://doi.org/10.5065/fppm-1g21 |
| OpenSky Citable URL | https://n2t.net/ark:/85065/d7jd528j |
| OpenSky Listing | View on OpenSky |
| CGD Affiliations | AMP |