Improving Bulk Microphysics Parameterizations in Simulations of Aerosol Effects

TitleImproving Bulk Microphysics Parameterizations in Simulations of Aerosol Effects
Publication TypeJournal Article
Year of Publication2013
JournalJournal of Geophysical Research - Atmospheres
Pages1-19
Date Published06/2013
Abstract / Summary

DOE scientists at Pacific Northwest National Laboratory, in collaboration with Texas A&M University, led the improvement of the double-moment bulk microphysical parameterization presently implemented in the Weather Research and Forecasting model. Replacing the prescribed aerosols in the original bulk scheme with a prognostic double-moment aerosol representation, researchers achieved a better parameterization than ever before. The team evaluated the improved parameterization with observations and simulations with the explicit bin cloud microphysics by conducting modeling experiments for two distinct cloud regimes–maritime warm stratocumulus clouds over the southeast Pacific Ocean from the VAMOS Ocean-Cloud-Atmosphere-Land Study (VOCALS) project, and continental deep convective clouds in the southeast of China. They found the improved scheme does a much better job than the original in terms of simulating precipitation and cloud microphysical properties. Sensitivity experiments using four different types of auto conversion schemes revealed that the auto conversion parameterization was crucial to determine the raindrop number, mass concentration, and drizzle formation for warm stratocumulus clouds. An embryonic raindrop size of 40 μm is a more realistic setting in the auto conversion parameterization. With the better bulk microphysical parameterization, scientists can more accurately simulate clouds and precipitation, and regional and global models can provide a more accurate assessment of aerosol indirect effects.

URLhttp://onlinelibrary.wiley.com/doi/10.1002/jgrd.50432/abstract
DOI10.1002/jgrd.50432
Journal: Journal of Geophysical Research - Atmospheres
Year of Publication: 2013
Pages: 1-19
Date Published: 06/2013

DOE scientists at Pacific Northwest National Laboratory, in collaboration with Texas A&M University, led the improvement of the double-moment bulk microphysical parameterization presently implemented in the Weather Research and Forecasting model. Replacing the prescribed aerosols in the original bulk scheme with a prognostic double-moment aerosol representation, researchers achieved a better parameterization than ever before. The team evaluated the improved parameterization with observations and simulations with the explicit bin cloud microphysics by conducting modeling experiments for two distinct cloud regimes–maritime warm stratocumulus clouds over the southeast Pacific Ocean from the VAMOS Ocean-Cloud-Atmosphere-Land Study (VOCALS) project, and continental deep convective clouds in the southeast of China. They found the improved scheme does a much better job than the original in terms of simulating precipitation and cloud microphysical properties. Sensitivity experiments using four different types of auto conversion schemes revealed that the auto conversion parameterization was crucial to determine the raindrop number, mass concentration, and drizzle formation for warm stratocumulus clouds. An embryonic raindrop size of 40 μm is a more realistic setting in the auto conversion parameterization. With the better bulk microphysical parameterization, scientists can more accurately simulate clouds and precipitation, and regional and global models can provide a more accurate assessment of aerosol indirect effects.

DOI: 10.1002/jgrd.50432
Citation:
2013.  "Improving Bulk Microphysics Parameterizations in Simulations of Aerosol Effects."  Journal of Geophysical Research - Atmospheres 1-19.  https://doi.org/10.1002/jgrd.50432.