Collaborative Research: A Synergistic Study of Aerosol Vertical Distributions and their Effects on Convective Clouds and Precipitation

Atmospheric aerosols, such as fine particles from the incomplete combustion of fossil fuels, wood and other fuels, can modify cloud formations and precipitation. Thus, they have profound impacts on the Earth’s weather and climate systems. The lack of understanding of complex aerosol properties, aerosol-cloud interactions, and aerosol variations in space and time contributes to large uncertainties in the climate assessment and projection.

The project aims to investigate how aerosols vary vertically and how aerosols influence cloud development and properties over a large area. Findings of this project are expected to advance our knowledge on aerosol-cloud interactions and address uncertainties in climate change studies. This research project will provide opportunities to integrate research and education by involving underrepresented minority students to conduct the research and incorporating the outcomes from this research into classes at University of California at Los Angeles and California Institute of Technology.

The overarching objective of this research is to characterize the vertical distributions of various types of aerosols and to study their impacts on convective clouds and precipitation through a combination of data analysis based on state-of-the-art satellite data and in situ measurements, as well as aerosol-aware and cloud-resolving WRF modeling. The key scientific questions are (1) what are the specific characteristics and seasonal and regional variations of the vertical distribution of different aerosol types? (2) how do the vertical distributions of various aerosol types affect the micro- and macro-physical properties of convective clouds and the associated precipitation?

Three specific tasks will be performed to answer these questions: (1) to examine the specific and unique characteristics of the vertical distributions of various aerosol types in different regions and seasons; (2) to investigate the relationships between vertical distributions of various aerosol types and convective clouds and associated precipitation; (3) to disentangle different aerosol effects (i.e., microphysical effect and radiative effect) as well as meteorological influence, and assess effects of aerosol vertical distributions on convective clouds and precipitation on the seasonal timescale using process-level models. Results from observational analyses will be used to evaluate and constrain model simulations to reduce the uncertainties associated with aerosol-cloud-precipitation interactions.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.