The influence of chemical composition and mixing state of Los Angeles urban aerosol on CCN number and cloud properties

Cubison, M. J.; Ervens, B.; Feingold, Graham; Docherty, K. S.; Ulbrich, I. M.; Shields, Laura G.; Prather, Kimberly A.; Hering, Susanne V.; Jiménez, José

doi:10.5194/acp-8-5649-2008

Cited by 177 publications

(197 citation statements)

References 105 publications

(117 reference statements)

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“…The size distribution of LOA supports the interpretation that this component is locally produced, probably by industrial combustion. In addition, these size distributions are less noisy and likely more robust than those obtained previously by tracer methods, and could be used for future cloud condensation nuclei (CCN) and hygroscopicity studies (Cubison et al, 2008;Gunthe et al, 2009;.…”

Section: Discussionmentioning

confidence: 99%

“…First, we can compare the static size distributions from the 3-vector model with the average size distributions from the vector-matrix model. Second, we can compare the dynamic diurnal average size distributions from the vector-matrix to size distributions estimated from tracer m/z's Cubison et al, 2008;Wang et al, 2010).…”

Section: Evaluation Of the Assumptions Of The 3-vector Modelmentioning

confidence: 99%

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Three-dimensional factorization of size-resolved organic aerosol mass spectra from Mexico City

et al. 2012

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Abstract.A size-resolved submicron organic aerosol composition dataset from a high-resolution time-of-flight mass spectrometer (HR-ToF-AMS) collected in Mexico City during the MILAGRO campaign in March 2006 is analyzed using 3-dimensional (3-D) factorization models. A method for estimating the precision of the size-resolved composition data for use with the factorization models is presented here for the first time. Two 3-D models are applied to the dataset. One model is a 3-vector decomposition (PARAFAC model), which assumes that each chemical component has a constant size distribution over all time steps. The second model is a vector-matrix decomposition (Tucker 1 model) that allows a chemical component to have a size distribution that varies in time. To our knowledge, this is the first report of an application of 3-D factorization models to data from fast aerosol instrumentation, and the first application of this vector-matrix model to any ambient aerosol dataset. A larger number of degrees of freedom in the vector-matrix model enable fitting real variations in factor size distributions, but also make the model susceptible to fitting noise in the dataset, giving some unphysical results. For this dataset and model, more physically meaningful results were obtained by partially constraining the factor mass spectra using a priori information and a new regularization method. We find four factors with each model: hydrocarbon-like organic aerosol (HOA), biomass-burning organic aerosol (BBOA), oxidized organic aerosol (OOA), and a locally occurring organic aerosol (LOA). These four factors have previously been reported from 2-dimensional factor analysis of the highresolution mass spectral dataset from this study. The size distributions of these four factors are consistent with previous reports for these particle types. Both 3-D models produce useful results, but the vector-matrix model captures real variability in the size distributions that cannot be captured by the 3-vector model. A tracer m/z-based method provides a useful approximation for the component size distributions in this study. Variation in the size distributions is demonstrated in a case study day with a large secondary aerosol formation event, in which there is evidence for the coating of HOA-containing particles with secondary species, shifting the HOA size distribution to larger particle sizes. These 3-D factorizations could be used to extract size-resolved aerosol composition data for correlation with aerosol hygroscopicity, cloud condensation nuclei (CCN), and other aerosol impacts. Furthermore, other fast and chemically complex 3-D datasets, including those from thermal desorption or chromatographic separation, could be analyzed with these 3-D factorization models. Applications of these models to new datasets requires careful construction of error estimates and appropriate choice of models that match the underlying structure of those data. Factorization studies with these 3-D datasets have the potential to provide further insights into organic aero...

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Section: Discussionmentioning

confidence: 99%

Section: Evaluation Of the Assumptions Of The 3-vector Modelmentioning

confidence: 99%

Three-dimensional factorization of size-resolved organic aerosol mass spectra from Mexico City

et al. 2012

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“…In the case of absorbed particles, not only the mass concentration but also their composition, the size distribution of both aerosol particles and cloud droplets, and the mixing state (external; internal homogeneous; core/shell) have a strong effect on the interaction with solar radiation Cubison et al, 2008;Péré et al, 2009;Jacobson, 2012).…”

Section: Radiative Effects Of Gases and Aerosolsmentioning

confidence: 99%

Online coupled regional meteorology chemistry models in Europe: current status and prospects

et al. 2014

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Published by Copernicus Publications on behalf of the European Geosciences Union. A. Baklanov et al.: Online coupled regional meteorology chemistry models in EuropeAbstract. Online coupled mesoscale meteorology atmospheric chemistry models have undergone a rapid evolution in recent years. Although mainly developed by the air quality modelling community, these models are also of interest for numerical weather prediction and regional climate modelling as they can consider not only the effects of meteorology on air quality, but also the potentially important effects of atmospheric composition on weather. Two ways of online coupling can be distinguished: online integrated and online access coupling. Online integrated models simulate meteorology and chemistry over the same grid in one model using one main time step for integration. Online access models use independent meteorology and chemistry modules that might even have different grids, but exchange meteorology and chemistry data on a regular and frequent basis. This article offers a comprehensive review of the current research status of online coupled meteorology and atmospheric chemistry modelling within Europe. Eighteen regional online coupled models developed or being used in Europe are described and compared. Topics discussed include a survey of processes relevant to the interactions between atmospheric physics, dynamics and composition; a brief overview of existing online mesoscale models and European model developments; an analysis on how feedback processes are treated in these models; numerical issues associated with coupled models; and several case studies and model performance evaluation methods. Finally, this article highlights selected scientific issues and emerging challenges that require proper consideration to improve the reliability and usability of these models for the three scientific communities: air quality, numerical meteorology modelling (including weather prediction) and climate modelling. This review will be of particular interest to model developers and users in all three fields as it presents a synthesis of scientific progress and provides recommendations for future research directions and priorities in the development, application and evaluation of online coupled models.

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“…Broekhuizen et al (2006) and Cubison et al (2008) both show evidence that CCN closure can be improved with knowledge of size-dependent composition. Cubison et al (2008) also found that assumptions about the aerosol mixing state (internal or external) can adversely impact CCN predictions. They sampled aerosol near Los Angeles, California in an urban airmass.…”

Section: Ccn Closure Reviewmentioning

confidence: 99%

“…It was developed by Roberts and Nenes (2005) and has been used in many field programs and laboratory studies since its introduction (e.g. Medina et al, 2007;Ervens et al, 2007;Cubison et al, 2008;Quinn et al, 2008;Gunthe et al, 2009). Supersaturation (SS) is maintained in the CCN-100 4306 D. S. Ward and W. R. Cotton: Cold and transition season by imposing a tightly controlled temperature gradient on the sheath/sample flow within a moist growth chamber.…”

Section: Methodsmentioning

confidence: 99%

Cold and transition season cloud condensation nuclei measurements in western Colorado

Ward

Cotton

2011

Atmos. Chem. Phys.

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Abstract.Recent studies have shown that orographic precipitation and the water resources that depend on it in the Colorado Rocky Mountains are sensitive to the variability of the region's aerosols, whether emitted locally or from distant sources. However, observations of cloud droplet nucleating aerosols in western Colorado, climatologically upwind of the Colorado Rocky Mountains, have been limited to a few studies at a single, northern site. To address this knowledge gap, atmospheric aerosols were sampled at a ground site in southwestern Colorado and in low-level north to south transects of the Colorado Western Slope as part of the Inhibition of Snowfall by Pollution Aerosols (ISPA-III) field campaign. Total particle and cloud condensation nuclei (CCN) number concentrations were measured for a 24-day period in Mesa Verde National Park, in September and October 2009. Regression analysis showed a positive relationship between mid-troposphere atmospheric pressure to the west of the site and the total particle count at the ground site, but no similar statistically significant relationship was found for the observed CCN. These data were supplemented with particle and CCN number concentration, as well as particle size distribution measurements collected aboard the King Air platform during December 2009. A CCN closure attempt was performed and suggested that the sampled aerosol may have had a low hygroscopicity that changed little with the largescale wind direction. Together, the sampled aerosols from these field programs were characteristic of a rural continental environment with CCN number concentrations that varied slowly in time, and little in space along the Western Slope.

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The influence of chemical composition and mixing state of Los Angeles urban aerosol on CCN number and cloud properties

Cited by 177 publications

References 105 publications

Three-dimensional factorization of size-resolved organic aerosol mass spectra from Mexico City

Three-dimensional factorization of size-resolved organic aerosol mass spectra from Mexico City

Online coupled regional meteorology chemistry models in Europe: current status and prospects

Cold and transition season cloud condensation nuclei measurements in western Colorado

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