PhD Proposal: Amanda Vieira dos Santos

ADVISOR: Dr. Henrique Barbosa
CO-ADVISOR: Dr. Belay Demoz

TITLE: Controls of Planetary Boundary Layer Variability and Its Response Timescales to Transient Radiative Perturbations

ABSTRACT: The evolution of the Planetary Boundary Layer (PBL) is an important component of local weather, air quality, and climate dynamics. The PBL evolution is influenced by multiple interacting processes, including insolation, turbulent heat fluxes, cloud cover, and aerosol loading. However, many of these variables co-vary on seasonal and synoptic timescales, making it difficult to distinguish their individual contributions to PBL variability. Moreover, its response to transient radiative perturbations, such as solar eclipses and smoke plumes, and the accuracy with which atmospheric models capture these rapid adjustments remain not fully understood.

This proposal aims to further our understanding of the PBL processes, with a focus on the effects of aerosol-radiation interactions on the diurnal cycle of the boundary layer height. Specifically, we will investigate the variability of PBL height (PBLH) in the Baltimore-Washington DC region. Our preliminary analysis using radiosonde observations from a recent annular solar eclipse demonstrate that cloud cover modulates the PBL’s response timescale to these sudden energy reductions. We will extend this research by utilizing observations from smoke case studies to isolate the specific impacts of aerosol properties, such as AOD, single scattering albedo, and plume height, on PBL stability. Furthermore, we will also evaluate the performance of widely used reanalysis products (MERRA-2 and ERA-5) in simulating the dynamic response of the PBL to these sudden perturbations.