PhD Proposal: Anthony La Luna
Location
Physics : 401
Date & Time
May 6, 2024, 10:00 am – 12:00 pm
Description
ADVISOR: Dr. Zhibo Zhang
TITLE: Optical Properties and Radiative Impact of Realistic Asian Dust Particles
ABSTRACT: The radiative energy balance of the climate system, weather patterns, and air quality are all greatly affected by dust aerosols in the atmosphere. Remote sensing techniques such as satellite and ground-based lidar provide methods of observation for quantification of dust particles and their dynamics. To make these measurements, proper characterization of the dust physicochemical properties are important as they impact light scattering. Despite this, simplifications to morphology such as spheres or spheroids are often made for these particles in remote sensing and climate modeling investigations. Here, we use realistic Asian dust particles obtained from fourteen collected samples of individual particles from the Mauna Loa Observatory with focused ion-beam tomography [Conny et al., 2019]. The observed realistic dust shapes impose a meaningful constraint on retrieving dust optical properties. We conduct a thorough analysis of the influence of different attributes of dust particles on both lidar ratio (LR) and depolarization ratio (DPR), examining their implications for dust remote sensing through lidar. We explore the importance of size parameter, refractive index, and sphericity on the optical properties, particularly lidar backscattering properties, of Asian dust. To achieve this, we employed ADDA, a discrete dipole approximation program, to characterize LR and DPR of dust particles across various size parameters, linking these parameters to the physical characteristics of the particles. We then investigate the interactions between dust particles and sulfate pollution. Two coating schemes are devised to represent polluted dust and the lidar properties of these particles are calculated. We will then determine the bulk scattering properties of clean and polluted dust using the realistic dust shape library. This will be achieved by averaging the properties across a particle size distribution and coating the particles based on effective radius, surface area, and volume. Lastly, we will inspect the direct radiative effect of the realistic dust particles and determine the effect of sulfate on these properties.
TITLE: Optical Properties and Radiative Impact of Realistic Asian Dust Particles
ABSTRACT: The radiative energy balance of the climate system, weather patterns, and air quality are all greatly affected by dust aerosols in the atmosphere. Remote sensing techniques such as satellite and ground-based lidar provide methods of observation for quantification of dust particles and their dynamics. To make these measurements, proper characterization of the dust physicochemical properties are important as they impact light scattering. Despite this, simplifications to morphology such as spheres or spheroids are often made for these particles in remote sensing and climate modeling investigations. Here, we use realistic Asian dust particles obtained from fourteen collected samples of individual particles from the Mauna Loa Observatory with focused ion-beam tomography [Conny et al., 2019]. The observed realistic dust shapes impose a meaningful constraint on retrieving dust optical properties. We conduct a thorough analysis of the influence of different attributes of dust particles on both lidar ratio (LR) and depolarization ratio (DPR), examining their implications for dust remote sensing through lidar. We explore the importance of size parameter, refractive index, and sphericity on the optical properties, particularly lidar backscattering properties, of Asian dust. To achieve this, we employed ADDA, a discrete dipole approximation program, to characterize LR and DPR of dust particles across various size parameters, linking these parameters to the physical characteristics of the particles. We then investigate the interactions between dust particles and sulfate pollution. Two coating schemes are devised to represent polluted dust and the lidar properties of these particles are calculated. We will then determine the bulk scattering properties of clean and polluted dust using the realistic dust shape library. This will be achieved by averaging the properties across a particle size distribution and coating the particles based on effective radius, surface area, and volume. Lastly, we will inspect the direct radiative effect of the realistic dust particles and determine the effect of sulfate on these properties.
