Date of Award

1-1-2017

Language

English

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

College/School/Department

Department of Atmospheric and Environmental Sciences

Content Description

1 online resource (iii, xviii, 152 pages)

Dissertation/Thesis Chair

Qilong Min

Committee Members

Christopher Walcek, Mathias Vuille, Liming Zhou, Jiwen Fan

Keywords

Atlantic, Cloud Microphysics, Deep Convective Clouds, Ice Microphysics, Ice Nuclei, Tropical, Dust, Aerosols, Ice clouds, Convective clouds, Microphysics, Dust-fall, Meteorology

Subject Categories

Atmospheric Sciences

Abstract

Aerosol effects on cloud and precipitation formation remain a significant source of uncertainty in the study of weather and climate. Aerosols can impact cloud and precipitation formation by functioning as cloud condensation nuclei (CCN), giant cloud condensation nuclei (GCCN) and/or ice nuclei (IN) affecting subsequent cloud microphysical processes. Aerosol effects on clouds are tightly interconnected with cloud dynamic and thermodynamic variables, some of which are currently impossible or infeasible to observe with existing sensors. Numerical models can be used to untangle aerosols effects from cloud dynamics and thermodynamics, but model results can be affected by the complexity of the parameterizations used to represent cloud microphysical processes in the model. Deep convective clouds (DCC) are important sources of precipitation and play a strong role in both regional and global circulation, with tropical convection being particularly significant. However, understanding of ice processes within these clouds is still limited due to the dynamically and thermodynamically complexities of DCCs and the lack of parameterizations that directly connect ice formation with aerosols. Therefore, to better understand the impacts of dust aerosols on DCC systems reported by previous observational studies, a case study in the tropical eastern Atlantic was investigated using the Weather Research and Forecasting (WRF) model coupled with a Spectral Bin Microphysics (SBM) model. A detailed set of ice nucleation parameterizations linking ice formation with aerosol particles have been implemented in the SBM.

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