Type
Text
Type
Dissertation
Advisor
Hameed, Sultan | Knopf, Daniel A | Mak, John | Aller, Josephine Y | Koop, Thomas.
Date
2013-12-01
Keywords
Physical chemistry | aerosol, ice cloud, ice nucleation, microphysics, ocean, phytoplankton
Department
Department of Marine and Atmospheric Science.
Language
en_US
Source
This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree.
Identifier
http://hdl.handle.net/11401/77786
Publisher
The Graduate School, Stony Brook University: Stony Brook, NY.
Format
application/pdf
Abstract
Ice particles are ubiquitous in the atmosphere existing as the sole constituents of glaciated cirrus clouds or coexisting with supercooled liquid droplets in mixed-phase clouds. Aerosol particles serving as heterogeneous ice nuclei for ice crystal formation impact the global radiative balance by modification of cloud radiative properties, and thus climate. Atmospheric ice formation is not a well understood process and represents great uncertainty for climate prediction. The oceans which cover the majority of the earth's surface host nearly half the total global primary productivity and contribute to the greatest aerosol production by mass. However, the effect of biological activity on particle aerosolization, particle composition, and ice nucleation is not well established. This dissertation investigates the link between marine biological activity, aerosol particle production, physical/chemical particle characteristics, and ice nucleation under controlled laboratory conditions. Dry and humidified aerosol size distributions of particles from bursting bubbles generated by plunging water jets and aeration through frits in a seawater mesocosm containing bacteria and/or phytoplankton cultures, were measured as a function of biological activity. Total particle production significantly increases primarily due to enhanced aerosolization of particles ≤ 100 nm in diameter attributable to the presence and growth of phytoplankton. Furthermore, hygroscopicity measurements indicate primary organic material associated with the sea salt particles, providing additional evidence for the importance of marine biological activity for ocean derived aerosol composition. Ice nucleation experiments show that these organic rich particles nucleate ice efficiently in the immersion and deposition modes, which underscores their importance in mixed-phase and cirrus cloud formation processes. In separate ice nucleation experiments employing pure cultures of Thalassiosira pseudonana, Nannochloris atomus and Emiliania huxleyi, cells and cell fragments efficiently nucleate ice in the deposition mode, however, only T. pseudonana and N. atomus form ice in the immersion mode, presumably due to different cell wall compositions. This further corroborates the role of phytoplanktonic species for aerosolization of marine biogenic cloud active particles. Experimental data are used to parameterize marine biogenic particle fluxes and heterogeneous ice nucleation as a function of biological activity. The atmospheric implications of the results and their implementation into cloud and climate models are discussed. | 163 pages
Recommended Citation
Alpert, Peter Aaron, "Characteristics of Aerosolized Ice Forming Marine Biogenic Particles" (2013). Stony Brook Theses and Dissertations Collection, 2006-2020 (closed to submissions). 3564.
https://commons.library.stonybrook.edu/stony-brook-theses-and-dissertations-collection/3564