Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 18 of 18 for “"Mixing state"”.
-
Black carbon mixing state impacts on aerosol activation investigations using particle-resolved model simulations
… CCN properties of BC particles depend on the BC mixing state, i.e. which other species are present within one BC-containing particle. The BC mixing state, in turn, evolves by so-called aerosol aging processes such as condensation of atmospheric gaseous components and coagulation with other …
-
Black carbon mixing state in Paris during MEGAPOLI: Connecting particle resolved observation to particle resolved modeling
… allowed unprecedented insight into black carbon mixing state and associated aging processes, however it is difficult to fully exploit these measurements using traditional modal or sectional models. The particle resolved aerosol model PartMC-MOSAIC, on the other hand, is a suitable interface to …
-
Particle-resolved aerosol modeling on the regional scale – insights into importance of capturing aerosol mixing state
… it became possible to simulate the aerosol mixing state in great detail. However, previous applications of PartMC-MOSAIC have lacked spatial resolution, which only a three-dimensional chemical transport model can provide. To address this shortcoming, the goal of this thesis was to create a …
-
Coupling data science and numerical simulations to empower atmospheric and environmental research
… atmospheric and environmental research. However, state-of-the-art Earth System Models are subject to limitations because of the multiscale nature of the Earth system, where processes on scales smaller than the computational grid resolution remain unresolved and can only rely on simplified …
-
Investigation of the evolution of atmospheric particles with integration of the stochastic particle-resolved model PartMC-MOSAIC and atmospheric measurements
… mixture of a wide variety of species, and the mixing state can change during the evolution of particles in the ambient environment, leading to significantly different effects on the climate system compared to freshly emitted condition. With the recently-developed particle-resolved model …
-
Particle-resolved modeling for evaluating assumptions in aerosol studies
… is introduced in quantifying observed aerosol mixing states due to a limited particle sample size. We used the particle-resolved model PartMC-MOSAIC to generate a scenario library that encompasses a large number of reference particle populations with a wide range of mixing states, quantified by …
-
Single-particle instrument simulator: Bridging experiments and models
Aerosol mixing state, the distribution of chemical species across individual aerosol particles, is crucial for quantifying aerosol optical, chemical, and micro-physical properties. For example, a particle’s absorptivity depends on whether light-absorbing components such as black carbon are …
-
Sub-grid process analysis of the sensitivity of black carbon aging to particle microphysical properties at emission
… capable of resolving changes in the particle mixing state owing to coagulation and condensation. We simulated black carbon-containing particles of varied size emitted into an idealized urban plume of varied local pollution and environmental conditions. We assessed the sensitivity of properties …
-
Investigating the impacts of entrainment on nucleation scavenging of black carbon particles through particle-resolved simulations
… per-particle chemical species composition, or mixing state. Challenges arise in determining black carbon climate effects because the mixing state changes during the particles’ transport in the atmosphere. By condensation of semi-volatile substances, coagulation, and photochemical processes, …
-
Volatility properties of the ambient and laboratory generated aerosol
… VBS, we estimated the volatility-based aerosol mixing state. Our observations show that aerosols were externally mixed most of the time. The extent of aerosol mixing state varies from season to season and among biomass burning events. In general, the extent of external mixing increases as the …
-
Modeling study of the hygroscopic, optical, and cloud-activation properties of aerosols from biofuel combustion
… providing information on the size distribution, mixing state, hygroscopicity, optical properties, CCN activity, and total quantity of aerosols emitted from biofuel combustion. The change in cloud characteristics due to biofuel burning aerosols is uncertain, in part, due to the uncertainty in the …
-
Real time analysis of atmospheric single particles in urban environments using aerosol time of flight mass spectrometry
… of the ATOFMS in providing composition and mixing state information on atmospheric particles at high time resolution. However they also show its limitations in delivering quantitative information directly.
-
Investigating the pH of atmospheric fine particles and implications for atmospheric chemistry
… pH with particle size above 1µm depending on mixing state but have little effect on PM1 pH. Ion balance or molar ratio, are not accurate pH proxy and highly sensitive to observational uncertainties. Impacts of low particle pH were investigated, including the effects on aerosol nitrate trends …
-
Characterisation of atmospheric single particles in industrial and regional background environments using aerosol time of flight mass spectrometry
… in providing source-specific composition and mixing state information on atmospheric particles at high time resolution.
-
Exploring the absorption properties and direct radiative impact of atmospheric carbonaceous aerosols
… aircraft campaigns in the continental United States. The BrC absorption properties from biomass burning estimated based on laboratory measurements are found to overestimate the direct measurements of ambient BrC absorption. In addition, applying a photochemical aging scheme for BrC improves …
-
Idealized particle-resolved large-eddy simulations to evaluate the impact of emissions spatial heterogeneity on CCN activity
… emissions spatial heterogeneity on the aerosol state are investigated, including effects on the aerosol number and mass distribution, composition, hygroscopicity, mixing state, and CCN activity. We find that CCN concentrations at low supersaturations (S=0.1–0.3%) increase in the upper PBL by up …