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Your search keyword '"O'Meara, Simon Patrick"' showing total 4 results
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4 results on '"O'Meara, Simon Patrick"'

3. Estimating the Volatility of Aerosol Components and Diffusion Through the Particle-Phase

Author

O'Meara, Simon Patrick, TOPPING, DAVID DO, Mcfiggans, Gordon, and Topping, David

Subjects
Diffusion, Atmospheric Science, Vapour Pressures, Atmospheric Chemistry, Environmental Science, Particulate Matter, Aerosol, Atmospheric Physics
Abstract

Accurate models of aerosol transformation including partitioning between the gas- and particle-phase are needed for estimating their effects on climate and air quality. In this thesis, the process of partitioning between phases and its determining factors are introduced and investigated. Three studies assess: the accuracy of estimation methods for aerosol component volatility and its effect on particulate concentration and composition; the consistency of different solutions to models of particle-phase diffusion; and, a method to analytically solve particle-phase diffusion. These studies contribute to the ongoing effort of improving aerosol models, such that their wide-ranging effects can be accurately estimated. Particulate matter suspended in the atmosphere affects both human health and climate. In order to understand these effects, a detailed knowledge of the processes determining how particulate matter is formed, and transformed with regards to physical and chemical properties such as size and composition, is required. To this end, this thesis demonstrates work that improves our ability to estimate the volatility of components that may contribute to particulate matter and improves our ability to simulate diffusion through it. The findings contribute to knowledge of how best to simulate particulate matter and its transformations and therefore its affect on health and climate.

Published
2017

4. PyCHAM (v1.3.4): a Python box model for simulating aerosol chambers.

Author

O'Meara, Simon Patrick, Xu, Shuxuan, Topping, David, Alfarra, M. Rami, Capes, Gerard, Lowe, Douglas, and McFiggans, Gordon

Subjects
*AEROSOLS, *GRAPHICAL user interfaces, *ORDINARY differential equations, *PYTHON programming language, *MODULAR construction, *COAGULATION, *MICROBIOLOGICAL aerosols
Abstract

In this paper the CHemistry with Aerosol Microphysics in Python (PyCHAM) box model software for aerosol chambers is described and assessed against benchmark simulations for accuracy. The model solves the coupled system of ordinary differential equations for gas-phase chemistry, gas-particle partitioning and gas-wall partitioning. Additionally, it can solve for coagulation, nucleation and particle loss to walls. PyCHAM is open source, whilst the graphical user interface, modular structure, manual and suite of tests for troubleshooting and tracking the effect of modifications to individual modules have been designed for optimal usability. In this paper, the modelled processes are individually assessed against benchmark simulations, and key parameters described. Examples of output when processes are coupled are also provided. Sensitivity of individual processes to relevant parameters is illustrated along with convergence of model output with increasing temporal and spatial resolution. The latter sensitivity analysis informs our recommendations for model setup. Where appropriate, parameterisations for specific processes have been chosen for their general applicability with their rationale detailed here. It is intended that PyCHAM aids the design and analysis of aerosol chamber experiments, with comparison of simulations against observations allowing improvement of process understanding that can be transferred to ambient atmosphere simulations. [ABSTRACT FROM AUTHOR]

Published
2020
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