This is a past event.

Please join ATM graduate students, Zaid Bakri and Swafuva Varappillikudy Sulaiman for their presentations on Monday, April 14 at 4 PM - Fisher Hall 125.

Zaid Bakri (Advisor: Claudio Mazzoleni)

HIGH SPATIAL RESOLUTION RETRIEVAL OF CLOUD DROPLET SIZE DISTRIBUTIONS USING POLARIZED SCATTERING IN THE CLOUDBOW ANGULAR RANGE

Clouds interact with solar and thermal radiation through the absorption and scattering of light. These interactions are determined by the size distributions of cloud droplets, which affect their optical properties and impact climate and the Earth's radiative budget. Usually, cloud droplet size distributions (DSDs) are retrieved by measuring the polarized scattered sunlight in the cloudbow angular range (~140°-165°). In this research, I am presenting a new method to measure the linearly polarized light scattered by droplets within the range (140°-145°) determined by optimized Lorenz-Mie simulations for a range of illumination wavelengths, i.e., Red (638 nm), Green (525 nm), and Blue (450 nm). These simulations have shown that linearly polarized intensities can segregate between different Gamma size distributions based on their different effective variance and effective radius values especially at a scattering angle of 140°. Therefore, I am introducing a DSD retrieval algorithm that can analyze the light beams scattered within fine angular increments in a narrow field-of-view (FOV) to retrieve cloud DSD from cloud targets in the order of ~10 cm inside the π-chamber at Tech. This approach is aimed at investigating the cloud DSD at scales smaller than those that airborne and spaceborne polarimetric measurements can access in the real clouds.

Swafuva Varappillikudy Sulaiman (Advisor: Will Cantrell)

AEROSOL COMPOSITION IN HYGROSCOPIC BURN-IN-PLACE FLARES: INSIGHTS INTO CLOUD SEEDING AND PRECIPITATION ENHANCEMENT

Understanding the complexities of aerosols is crucial in advancing our knowledge of cloud microphysics, radiative forcing, and air quality. Aerosols influence cloud formation by acting as cloud condensation nuclei (CCN), thereby playing a pivotal role in cloud microphysics and precipitation processes. Quantifying their chemical composition is essential, particularly in evaluating the effectiveness of cloud seeding flares in precipitation enhancement experiments. In this study, I present preliminary results from Scanning Electron Microscopy (SEM) coupled with Energy Dispersive X-ray Spectroscopy (EDX) analysis. These techniques provide valuable insights into the size and chemical mapping of aerosols. Such detailed characterization allows for a better understanding of how aerosol hygroscopicity is influenced by their mixing state. These findings are critical for assessing the efficiency of aerosol particles as CCN and, ultimately, their potential in weather modification strategies.