This is a past event.

Please join this week's Atmospheric Sciences Graduate Student Presenters, Hamed Fahandezh Sadi (Physics) and Shreya Joshi (Physics) for their in-person presentations on Monday, March 18th at 4 PM - Fisher Hall 101.

Hamed Fahandezh Sadi (Physics) [Advisor: Dr. Raymond Shaw]

Haze-cloud Interactions in Turbulent Convection: Explorations with the Pi Chamber and the Pi-Parcel Model

The process of cloud formation is influenced by various atmospheric factors, including supersaturation and aerosol properties such as size, concentration, and composition. Pi chamber experiments show that the supersaturation and the aerosol properties can result in a transition from single-mode to bimodal droplet size distributions, with the small mode corresponding to unactivated haze droplets. Pi Parcel model simulations show that the haze and cloud modes can interact, leading to oscillation in droplet concentration, liquid water, and supersaturation. We explored the role of various types of aerosol particles, including oil aerosols produced with a Lamer Generator, to explore their activation and growth processes through the bimodal shape of the droplet size distribution. One goal is to determine the critical radius from the measurements, and to that end, we examined various theories relevant to the activation of oil aerosols.

Shreya Joshi (Physics) [Advisor: Dr. Claudio Mazzoleni]

Light Absorbing Aerosol Cloud Interactions

Atmospheric aerosols that absorb light, especially those containing black carbon (BC) particles, are pivotal in shaping Earth's radiation balance. They interact with solar radiation by scattering and absorbing light and influence cloud formation and characteristics. BC particles originate from the incomplete combustion of carbon-based fuels and undergo various transformations while traversing the atmosphere, due to interactions with other atmospheric species or clouds. These transformations can modify the particles' interactions with both light and clouds. The Light-absorbing Aerosol-Cloud Interactions (LAACI) project, utilizing Michigan Tech's Pi Chamber cloud chamber, investigates the evolution of these aerosols upon cloud interaction. In our research, we utilized a BC surrogate (cab-o-jet) and a surrogate for coating materials (liquid smoke) to understand the effects of aerosol-cloud interactions. We established a technique for applying the surrogate coating onto BC surrogate particles and for the collection of cloud processed aerosols using a Pumped Counterflow Virtual Impactor (PCVI) for subsequent analysis. We examined the morphological, optical, and chemical properties of BC particles before and after their interaction with clouds in the chamber. This analysis provided deeper insight into how the progression of these particles influences their characteristics and, subsequently, their impact on the atmosphere.