Contact Information
General Enquiry
| Fax: | +(852)-3442-0688 |
|---|---|
| Email: | see.enquiry@cityu.edu.hk |
| Address: | G5703, 5/F, Yeung Kin Man Academic Building (YEUNG), City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR |
https://cityu.zoom.us/j/94222826342
Meeting ID: 942 2282 6342
Password: 235058
Aerosol particles are ubiquitous in the atmosphere. Aerosols can significantly influence regional and global climate, by scattering and absorbing solar radiation, and by serving as nuclei in cloud formation. A large fraction of the sub-micrometer particle mass consists of organic material. The properties and climate effects of organic aerosols remain highly uncertain.
In the first part of my talk, I will give an overview of thin-film-based experimental approaches that I developed to characterize the climate-relevant properties of organic aerosols. We have successfully applied these approaches to measure the optical constants, in-particle diffusivity, volatility, hygroscopicity, and photo-lability of organic aerosols in laboratory experiments. These properties can determine the atmospheric lifetime of organic aerosols, their interactions with solar radiation and surrounding gaseous species, and ultimately their climate effects.
Accurate assessments of the aerosol climate forcing also require an improved understanding of how the aerosol concentration changes from the preindustrial baseline to the present day. In the second part of my talk, I will introduce our improved estimates of fire aerosol emissions over the past 250 years in the Southern Hemisphere. The new fire emission scenario was validated against multiple Antarctic ice core records. Using the new fire emissions, the reassessment of aerosol radiative forcing in the Southern Hemisphere is about 30% less cooling than that estimated based on current emission inventories widely used in climate models.
Dr. Pengfei Liu received both Bachelor’s (2008) and Master’s (2011) degrees in Atmospheric Sciences from Peking University. He pursued his PhD at Harvard in 2017, where he worked in the lab of Prof. Scot Martin on laboratory experiments of organic aerosols. After PhD, he worked as a Postdoc Fellow in the Atmospheric Chemistry Modeling Group at Harvard under the supervision of Dr. Loretta Mickley. He joined Georgia Tech as an Assistant Professor in the School of Earth and Atmospheric Sciences in 2020.