Date of Award
December 2024
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Atmospheric Sciences
First Advisor
Jianglong Zhang
Abstract
With the enhanced Arctic warming and sea ice melting in recent decades, this study seeks to expand our understanding of how atmospheric aerosols affect the Arctic radiative budget, on both weather and climate scales. On climate scales, the study of the impact of atmospheric aerosols on Arctic radiative budget, through observation-based methods, remains challenging due to the complicated surface conditions including sea ice, open oceans, and land surfaces. Using satellite observations from the Ozone Monitoring Instrument (OMI), the Moderate Resolution Imaging Spectroradiometer (MODIS), the Cloud and the Earth Radiant Energy System (CERES), and the Special Sensor Microwave Imager / Sounder (SSMIS), and observation-based methods, we studied the spatiotemporal variations of ultraviolet (UV)-absorbing aerosol plumes over the Arctic region. With the assistance of artificial intelligence-based methods, we found that increases in absorbing aerosols such as biomass burning (BB) smoke in the Arctic can cause significant regional top of atmosphere (TOA) radiative flux changes, though Arctic-wide changes are rather small. On weather scales, though BB smoke aerosol particles are typically assumed to have negligible impacts at the thermal infrared (TIR) wavelengths due to their smaller particle size than the TIR wavelength, significant longwave cooling signals were found to be repeatedly observable from satellite observations in dense smoke plumes regions. With the combined use of satellite- and ground-based observations, as well as radiative transfer model simulations, we explored the causes for the unexpected smoke aerosol IR signatures. While enhanced smoke plume water vapor may cause some impacts on water vapor-sensitive infrared channels, we found that shadow-induced surface cooling beneath the smoke is the primary cause of the observable TIR cooling. The dense smoke-induced TIR cooling reduces the upwelling longwave flux (LWF) in the plume region, suggesting that smoke aerosols may be more radiative neutral than currently believed, and these impacts could also affect the Arctic radiative budget.
Recommended Citation
Sorenson, Blake Thomas, "Observational Analyses Of Aerosol Radiative Impacts On Weather And Climate Scales" (2024). Theses and Dissertations. 6571.
https://commons.und.edu/theses/6571