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PhD Defense: Qianqian Song


Physics : 401

Date & Time

June 29, 2022, 9:00 am11:00 am


ADVISORS: Dr. Zhibo Zhang

TITLE: Observation-constrained Direct Radiative Effects of Dust Aerosols

ABSTRACT: Mineral dust aerosols play an important role in modulating the radiative energy budget of Earth-Atmosphere system on regional to global scales through their interactions with both solar and thermal infrared radiations, which is known as the direct radiative effects (DRE). The DRE of dust not only influences the global energy balance, but also affects surface temperature, precipitation, atmospheric circulation, atmospheric and oceanic heat transport and so on. The focus of my Ph.D. study is to derive the observation-constrained DRE of dust. Starting with the tropical north Atlantic region (NA), we first developed a novel method to infer the instantaneous DRE efficiency of dust directly from satellite observation without making any assumptions about dust particle composition and shapes. This strong observation constrain is then used to identify an optimal dust model for more comprehensive DRE computations such as the diurnal variation. Next, we derived two observation-based global monthly mean dust Aerosol Optical Depth (DAOD) climatological datasets based on active (CALIOP) and passive (MODIS) observations. We investigated the seasonal to interannual variations of DAOD in several key regions and identified interesting and important decreasing tread of dust in the Asian and Northwest Pacific regions. These observational DAOD datasets provide the basis for our most recent study of the size-resolved dust DRE efficiency (DREE). The results demonstrate that our observation-based size-resolved dust DREE can be used in combination of any DAOD and dust particle size to estimate the global DRE. Based on it, we carried out a comprehensive sensitivity study which suggests dust refractive indices, which is closely related to dust mineralogy, to be the most dominant uncertainty, in comparison with DAOD and dust particle size and shape, in the estimates of global dust DRE.

Qianqian Song's Ph.D. defense
Hosted by Zhibo Zhang

Wednesday, Jun 29, 2022 9:00 am | 3 hours 15 minutes | (UTC-04:00) Eastern Time (US & Canada)
Meeting number: 2624 210 4868
Password: ycRRk8w9dG4

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