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1. Anthropogenic influences on the physical state of submicron particulate matter over a tropical forest

Author

Bateman, AP, Gong, Z, Harder, TH, De Sá, SS, Wang, B, Castillo, P, China, S, Liu, Y, O'Brien, RE, Palm, BB, Shiu, HW, Cirino, GG, Thalman, R, Adachi, K, Lizabeth Alexander, M, Artaxo, P, Bertram, AK, Buseck, PR, Gilles, MK, Jimenez, JL, Laskin, A, Manzi, AO, Sedlacek, A, Souza, RAF, Wang, J, Zaveri, R, and Martin, ST

Subjects
Meteorology & Atmospheric Sciences, Atmospheric Sciences, Astronomical and Space Sciences
Abstract

The occurrence of nonliquid and liquid physical states of submicron atmospheric particulate matter (PM) downwind of an urban region in central Amazonia was investigated. Measurements were conducted during two intensive operating periods (IOP1 and IOP2) that took place during the wet and dry seasons of the GoAmazon2014/5 campaign. Air masses representing variable influences of background conditions, urban pollution, and regional-and continental-scale biomass burning passed over the research site. As the air masses varied, particle rebound fraction, an indicator of physical state, was measured in real time at ground level using an impactor apparatus. Micrographs collected by transmission electron microscopy confirmed that liquid particles adhered, while nonliquid particles rebounded. Relative humidity (RH) was scanned to collect rebound curves. When the apparatus RH matched ambient RH, 95ĝ€% of the particles adhered as a campaign average. Secondary organic material, produced for the most part by the oxidation of volatile organic compounds emitted from the forest, produces liquid PM over this tropical forest. During periods of anthropogenic influence, by comparison, the rebound fraction dropped to as low as 60ĝ€% at 95ĝ€% RH. Analyses of the mass spectra of the atmospheric PM by positive-matrix factorization (PMF) and of concentrations of carbon monoxide, total particle number, and oxides of nitrogen were used to identify time periods affected by anthropogenic influences, including both urban pollution and biomass burning. The occurrence of nonliquid PM at high RH correlated with these indicators of anthropogenic influence. A linear model having as output the rebound fraction and as input the PMF factor loadings explained up to 70ĝ€% of the variance in the observed rebound fractions. Anthropogenic influences can contribute to the presence of nonliquid PM in the atmospheric particle population through the combined effects of molecular species that increase viscosity when internally mixed with background PM and increased concentrations of nonliquid anthropogenic particles in external mixtures of anthropogenic and biogenic PM.

Published
2017

2. Estimating black carbon aging time-scales with a particle-resolved aerosol model

Author

Riemer, N., West, M., Zaveri, R. A., and Easter, R. C.

Subjects
Physics - Atmospheric and Oceanic Physics
Abstract

Understanding the aging process of aerosol particles is important for assessing their chemical reactivity, cloud condensation nuclei activity, radiative properties and health impacts. In this study we investigate the aging of black carbon containing particles in an idealized urban plume using a new approach, the particle-resolved aerosol model PartMC-MOSAIC. We present a method to estimate aging time-scales using an aging criterion based on cloud condensation nuclei activation. The results show a separation into a daytime regime where condensation dominates and a nighttime regime where coagulation dominates. For the chosen urban plume scenario, depending on the supersaturation threshold, the values for the aging time-scales vary between 0.06 hours and 10 hours during the day, and between 6 hours and 20 hours during the night.

Published
2009

3. Simulating the evolution of soot mixing state with a particle-resolved aerosol model

Author

Riemer, N., West, M., Zaveri, R. A., and Easter, R. C.

Subjects
Physics - Atmospheric and Oceanic Physics
Abstract

The mixing state of soot particles in the atmosphere is of crucial importance for assessing their climatic impact, since it governs their chemical reactivity, cloud condensation nuclei activity and radiative properties. To improve the mixing state representation in models, we present a new approach, the stochastic particle-resolved model PartMC-MOSAIC, which explicitly resolves the composition of individual particles in a given population of different types of aerosol particles. This approach accurately tracks the evolution of the mixing state of particles due to emission, dilution, condensation and coagulation. To make this direct stochastic particle-based method practical, we implemented a new multiscale stochastic coagulation method. With this method we achieved optimal efficiency for applications when the coagulation kernel is highly non-uniform, as is the case for many realistic applications. PartMC-MOSAIC was applied to an idealized urban plume case representative of a large urban area to simulate the evolution of carbonaceous aerosols of different types due to coagulation and condensation. For this urban plume scenario we quantified the individual processes that contribute to the aging of the aerosol distribution, illustrating the capabilities of our modeling approach. The results showed for the first time the multidimensional structure of particle composition, which is usually lost in internally-mixed sectional or modal aerosol models., Comment: Submitted to Journal of Geophysical Research

Published
2008
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5. Chemical evolution of volatile organic compounds in the outflow of the Mexico City Metropolitan area

Author

Apel, E. C, Emmons, L. K, Karl, T., Flocke, F., Hills, A. J, Madronich, S., Lee-Taylor, J., Fried, A., Weibring, P., Walega, J., Richter, D., Tie, X., Mauldin, L., Campos, T., Weinheimer, A., Knapp, D., Sive, B., Kleinman, L., Springston, S., Zaveri, R., Ortega, J., Voss, P., Blake, D., Baker, A., Warneke, C., Welsh-Bon, D., de Gouw, J., Zheng, J., Zhang, R., Rudolph, J., Junkermann, W., and Riemer, D. D

Subjects
proton-transfer-reaction, reaction mass-spectrometry, intercomparison experiment nomhice, characterizing ozone production, air-quality, formaldehyde measurements, nonmethane hydrocarbons, field campaigns, urban air, wrf-chem
Abstract

The volatile organic compound (VOC) distribution in the Mexico City Metropolitan Area (MCMA) and its evolution as it is uplifted and transported out of the MCMA basin was studied during the 2006 MILAGRO/MIRAGE-Mex field campaign. The results show that in the morning hours in the city center, the VOC distribution is dominated by non-methane hydrocarbons (NMHCs) but with a substantial contribution from oxygenated volatile organic compounds (OVOCs), predominantly from primary emissions. Alkanes account for a large part of the NMHC distribution in terms of mixing ratios. In terms of reactivity, NMHCs also dominate overall, especially in the morning hours. However, in the afternoon, as the boundary layer lifts and air is mixed and aged within the basin, the distribution changes as secondary products are formed. The WRF-Chem (Weather Research and Forecasting with Chemistry) model and MOZART (Model for Ozone and Related chemical Tracers) were able to approximate the observed MCMA daytime patterns and absolute values of the VOC OH reactivity. The MOZART model is also in agreement with observations showing that NMHCs dominate the reactivity distribution except in the afternoon hours. The WRF-Chem and MOZART models showed higher reactivity than the experimental data during the nighttime cycle, perhaps indicating problems with the modeled nighttime boundary layer height. A northeast transport event was studied in which air originating in the MCMA was intercepted aloft with the Department of Energy (DOE) G1 on 18 March and downwind with the National Center for Atmospheric Research (NCAR) C130 one day later on 19 March. A number of identical species measured aboard each aircraft gave insight into the chemical evolution of the plume as it aged and was transported as far as 1000 km downwind; ozone was shown to be photochemically produced in the plume. The WRF-Chem and MOZART models were used to examine the spatial extent and temporal evolution of the plume and to help interpret the observed OH reactivity. The model results generally showed good agreement with experimental results for the total VOC OH reactivity downwind and gave insight into the distributions of VOC chemical classes. A box model with detailed gas phase chemistry (NCAR Master Mechanism), initialized with concentrations observed at one of the ground sites in the MCMA, was used to examine the expected evolution of specific VOCs over a 1-2 day period. The models clearly supported the experimental evidence for NMHC oxidation leading to the formation of OVOCs downwind, which then become the primary fuel for ozone production far away from the MCMA.

Published
2010

6. Emission and chemistry of organic carbon in the gas and aerosol phase at a sub-urban site near Mexico City in March 2006 during the MILAGRO study

Author

de Gouw, J. A, Welsh-Bon, D., Warneke, C., Kuster, W. C, Alexander, L., Baker, A. K, Beyersdorf, A. J, Blake, D. R, Canagaratna, M., Celada, A. T, Huey, L. G, Junkermann, W., Onasch, T. B, Salcido, A., Sjostedt, S. J, Sullivan, A. P, Tanner, D. J, Vargas, O., Weber, R. J, Worsnop, D. R, Yu, X. Y, and Zaveri, R.

Subjects
trap-mass-spectrometry, source apportionment, air-quality, formaldehyde measurements, ambient aerosols, hydrocarbon-like, field campaigns, high-resolution, fine-particle, atmosphere
Abstract

Volatile organic compounds (VOCs) and carbonaceous aerosol were measured at a sub-urban site near Mexico City in March of 2006 during the MILAGRO study (Megacity Initiative: Local and Global Research Objectives). Diurnal variations of hydrocarbons, elemental carbon (EC) and hydrocarbon-like organic aerosol (HOA) were dominated by a high peak in the early morning when local emissions accumulated in a shallow boundary layer, and a minimum in the afternoon when the emissions were diluted in a significantly expanded boundary layer and, in case of the reactive gases, removed by OH. In comparison, diurnal variations of species with secondary sources such as the aldehydes, ketones, oxygenated organic aerosol (OOA) and watersoluble organic carbon (WSOC) stayed relatively high in the afternoon indicating strong photochemical formation. Emission ratios of many hydrocarbon species relative to CO were higher in Mexico City than in the U. S., but we found similar emission ratios for most oxygenated VOCs and organic aerosol. Secondary formation of acetone may be more efficient in Mexico City than in the U. S., due to higher emissions of alkane precursors from the use of liquefied petroleum gas. Secondary formation of organic aerosol was similar between Mexico City and the U. S. Combining the data for all measured gas and aerosol species, we describe the budget of total observed organic carbon (TOOC), and find that the enhancement ratio of TOOC relative to CO is conserved between the early morning and mid afternoon despite large compositional changes. Finally, the influence of biomass burning is investigated using the measurements of acetonitrile, which was found to correlate with levoglucosan in the particle phase. Diurnal variations of acetonitrile indicate a contribution from local burning sources. Scatter plots of acetonitrile versus CO suggest that the contribution of biomass burning to the enhancement of most gas and aerosol species was not dominant and perhaps not dissimilar from observations in the U.S.

Published
2009

7. Simulating organic aerosol in Delhi with WRF-Chem using the volatility-basis-set approach:exploring model uncertainty with a Gaussian process emulator

Author

Reyes-Villegas, E., Lowe, D., Johnson, J. S., Carslaw, K. S., Darbyshire, E., Flynn, Michael, Allan, J. D., Coe, Hugh, Chen, Y., Wild, O., Archer-Nicholls, Scott, Archibald, A., Singh, S., Shrivastava, M., Zaveri, R. A., Singh, Vikas, Beig, G., Sokhi, R., McFiggans, G., Reyes-Villegas, E., Lowe, D., Johnson, J. S., Carslaw, K. S., Darbyshire, E., Flynn, Michael, Allan, J. D., Coe, Hugh, Chen, Y., Wild, O., Archer-Nicholls, Scott, Archibald, A., Singh, S., Shrivastava, M., Zaveri, R. A., Singh, Vikas, Beig, G., Sokhi, R., and McFiggans, G.

Abstract

The nature and origin of organic aerosol in the atmosphere remain unclear. The gas–particle partitioning of semi-volatile organic compounds (SVOCs) that constitute primary organic aerosols (POAs) and the multigenerational chemical aging of SVOCs are particularly poorly understood. The volatility basis set (VBS) approach, implemented in air quality models such as WRF-Chem (Weather Research and Forecasting model with Chemistry), can be a useful tool to describe emissions of POA and its chemical evolution. However, the evaluation of model uncertainty and the optimal model parameterization may be expensive to probe using only WRF-Chem simulations. Gaussian process emulators, trained on simulations from relatively few WRF-Chem simulations, are capable of reproducing model results and estimating the sources of model uncertainty within a defined range of model parameters. In this study, a WRF-Chem VBS parameterization is proposed; we then generate a perturbed parameter ensemble of 111 model runs, perturbing 10 parameters of the WRF-Chem model relating to organic aerosol emissions and the VBS oxidation reactions. This allowed us to cover the model's uncertainty space and to compare outputs from each run to aerosol mass spectrometer observations of organic aerosol concentrations and O:C ratios measured in New Delhi, India. The simulations spanned the organic aerosol concentrations measured with the aerosol mass spectrometer (AMS). However, they also highlighted potential structural errors in the model that may be related to unsuitable diurnal cycles in the emissions and/or failure to adequately represent the dynamics of the planetary boundary layer. While the structural errors prevented us from clearly identifying an optimized VBS approach in WRF-Chem, we were able to apply the emulator in the following two periods: the full period (1–29 May) and a subperiod period of 14:00–16:00 h LT (local time) on 1–29 May. The combination of emulator analysis and model evaluation metrics

Published
2023

8. Unified theoretical framework for mixing state of black carbon

Author

Wang, J., Cai, R., Liu, C., Jiang, J., Nie, W., Moteki, N., Zaveri, R., Huang, X., Ma, N., Chen, G., Wang, Z., Jin, Y., Cai, J., Zhang, Y., Chi, X., Holanda, B., Xing, J., Liu, T., Qi, X., Wang, Q., Pöhlker, C., Su, H., Cheng, Y., Wang, S., Hao, J., Andreae, M., and Ding, A.

Abstract

Black carbon (BC) plays an important role in the climate system due to its strongwarming effect, yet the magnitude of this effect is highly uncertain due to the complex mixingstate of aerosols. Here we build a unified theoretical framework to describe BC’s mixing states,linking dynamic processes to BC coating thickness distribution, and show its self-similarity for sites in diverse environments. The size distribution of BC-containing particles is found to followan exponential pattern and is independent of BC core size. A mixing state module is establishedbased on this finding and successfully applied in global and regional models, which increases theaccuracy of aerosol climate effect estimations. Our theoretical framework can bridge the gap be-tween observation and model simulation in both mixing state description and light absorption quantification

Published
2022

12. The Messy Aerosol Submodel MADE3 (v2.0b): Description and a Box Model Test

Author

Kaiser, J. C, Hendricks, J, Righi, M, Riemer, N, Zaveri, R. A, Metzger, S, and Aquila, Valentina

Subjects
Meteorology And Climatology
Abstract

We introduce MADE3 (Modal Aerosol Dynamics model for Europe, adapted for global applications, 3rd generation), an aerosol dynamics submodel for application within the MESSy framework (Modular Earth Submodel System). MADE3 builds on the predecessor aerosol submodels MADE and MADE-in. Its main new features are the explicit representation of coarse particle interactions both with other particles and with condensable gases, and the inclusion of hydrochloric acid (HCl)chloride (Cl) partitioning between the gas and condensed phases. The aerosol size distribution is represented in the new submodel as a superposition of nine lognormal modes: one for fully soluble particles, one for insoluble particles, and one for mixed particles in each of three size ranges (Aitken, accumulation, and coarse mode size ranges). In order to assess the performance of MADE3 we compare it to its predecessor MADE and to the much more detailed particle-resolved aerosol model PartMC-MOSAIC in a box model simulation of an idealized marine boundary layer test case. MADE3 and MADE results are very similar, except in the coarse mode, where the aerosol is dominated by sea spray particles. Cl is reduced in MADE3 with respect to MADE due to the HClCl partitioning that leads to Cl removal from the sea spray aerosol in our test case. Additionally, aerosol nitrate concentration is higher in MADE3 due to the condensation of nitric acid on coarse particles. MADE3 and PartMC- MOSAIC show substantial differences in the fine particle size distributions (sizes about 2 micrometers) that could be relevant when simulating climate effects on a global scale. Nevertheless, the agreement between MADE3 and PartMC-MOSAIC is very good when it comes to coarse particle size distribution, and also in terms of aerosol composition. Considering these results and the well-established ability of MADE in reproducing observed aerosol loadings and composition, MADE3 seems suitable for application within a global model.

Published
2014
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13. Overview of the 2010 Carbonaceous Aerosols and Radiative Effects Study (CARES)

Author

Zaveri, R. A, Shaw, W. J, Cahill, J. F, Cairns, Brian, Cappa, C. D, Ottaviani, Matteo, Cziczo, D. J, Ferrare, Richard A, Alexander, M. L, Alexandrov, Mikhail Dmitrievic, Alvarez, R. J, Arnott, W. P, Atkinson, D. B, Schmid, B, Chand, D, China, S, Comstock, J. M, Dubey, M. K, Easter, R. C, Erickson, M. H, Fast, J. D, Flowers, B. A, Fortner, E, Baidar, S, Hair, J, Hostetler, C, Obland, M. D, Rogers, R. R, Floerchinger, C, Banta, R. M, Barnard, J. C, Beranek, J, Berg, L. K, Brechtel, F, and Brewer, W. A

Subjects
Environment Pollution, Meteorology And Climatology
Abstract

Substantial uncertainties still exist in the scientific understanding of the possible interactions between urban and natural (biogenic) emissions in the production and transformation of atmospheric aerosol and the resulting impact on climate change. The US Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) program's Carbonaceous Aerosol and Radiative Effects Study (CARES) carried out in June 2010 in Central Valley, California, was a comprehensive effort designed to improve this understanding. The primary objective of the field study was to investigate the evolution of secondary organic and black carbon aerosols and their climate-related properties in the Sacramento urban plume as it was routinely transported into the forested Sierra Nevada foothills area. Urban aerosols and trace gases experienced significant physical and chemical transformations as they mixed with the reactive biogenic hydrocarbons emitted from the forest. Two heavily-instrumented ground sites - one within the Sacramento urban area and another about 40 km to the northeast in the foothills area - were set up to characterize the evolution of meteorological variables, trace gases, aerosol precursors, aerosol size, composition, and climaterelated properties in freshly polluted and "aged" urban air. On selected days, the DOE G-1 aircraft was deployed to make similar measurements upwind and across the evolving Sacramento plume in the morning and again in the afternoon. The NASA B-200 aircraft, carrying remote sensing instruments, was also deployed to characterize the vertical and horizontal distribution of aerosols and aerosol optical properties within and around the plume. This overview provides: (a) the scientific background and motivation for the study, (b) the operational and logistical information pertinent to the execution of the study, (c) an overview of key observations and initial findings from the aircraft and ground-based sampling platforms, and (d) a roadmap of planned data analyses and focused modeling efforts that will facilitate the integration of new knowledge into improved representations of key aerosol processes and properties in climate models.

Published
2012
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14. Photoacoustic Optical Properties at UV, VIS, and near IR Wavelengths for Laboratory Generated and Winter Time Ambient Urban Aerosols

Author

Gyawali, M, Arnott, W. P, Zaveri, R. A, Song, C, Moosmuller, H, Liu, L, Mishchenko, M. I, Chen, L.-W.A, Green, M. C, Watson, J. G, and Chow, J. C

Subjects
Geophysics
Abstract

We present the laboratory and ambient photoacoustic (PA) measurement of aerosol light absorption coefficients at ultraviolet wavelength (i.e., 355 nm) and compare with measurements at 405, 532, 870, and 1047 nm. Simultaneous measurements of aerosol light scattering coefficients were achieved by the integrating reciprocal nephelometer within the PA's acoustic resonator. Absorption and scattering measurements were carried out for various laboratory generated aerosols, including salt, incense, and kerosene soot to evaluate the instrument calibration and gain insight on the spectral dependence of aerosol light absorption and scattering. Ambient measurements were obtained in Reno, Nevada, between 18 December 2009 and 18 January 2010. The measurement period included days with and without strong ground level temperature inversions, corresponding to highly polluted (freshly emitted aerosols) and relatively clean (aged aerosols) conditions. Particulate matter (PM) concentrations were measured and analyzed with other tracers of traffic emissions. The temperature inversion episodes caused very high concentration of PM (sub 2.5) and PM( sub 10) (particulate matter with aerodynamic diameters less than 2.5 micrometers and 10 micrometers, respectively) and gaseous pollutants: carbon monoxide (CO), nitric oxide (NO), and nitrogen dioxide (NO2). The diurnal change of absorption and scattering coefficients during the polluted (inversion) days increased approximately by a factor of two for all wavelengths compared to the clean days. The spectral variation in aerosol absorption coefficients indicated a significant amount of absorbing aerosol from traffic emissions and residential wood burning. The analysis of single scattering albedo (SSA), Angstrom exponent of absorption (AEA), and Angstrom exponent of scattering (AES) for clean and polluted days provides evidences that the aerosol aging and coating process is suppressed by strong temperature inversion under cloudy conditions. In general, measured UV absorption coefficients were found to be much larger for biomass burning aerosol than for typical ambient aerosols.

Published
2012
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15. NMR investigation of the quasi-brine layer in ice/brine mixtures

Author

H. Cho, Shepson, P.B., Barrie, L.A., Cowin, J.P., and Zaveri, R.

Subjects
Saline waters -- Research, Nuclear magnetic resonance -- Research, Chemicals, plastics and rubber industries
Abstract

The results of the high-resolution nuclear magnetic resonance (NMR) experiments in which (super 1)H and (super 23)Na are quantified in frozen saltwater solutions with a range of NaCl concentrations, and over the environmentally relevant temperature range 246-273 K are reported. They imply that highly concentrated liquid brines, known as quasi-brine layers (QBLs), can coexist with ice and solid NaCl.2H(sub 2)O at temperatures as low as 228 K.

Published
2002

16. Nitrate radicals and biogenic volatile organic compounds: oxidation, mechanisms and organic aerosol

Author

Ng, N. L., primary, Brown, S. S., additional, Archibald, A. T., additional, Atlas, E., additional, Cohen, R. C., additional, Crowley, J. N., additional, Day, D. A., additional, Donahue, N. M., additional, Fry, J. L., additional, Fuchs, H., additional, Griffin, R. J., additional, Guzman, M. I., additional, Hermann, H., additional, Hodzic, A., additional, Iinuma, Y., additional, Jimenez, J. L., additional, Kiendler-Scharr, A., additional, Lee, B. H., additional, Luecken, D. J., additional, Mao, J., additional, McLaren, R., additional, Mutzel, A., additional, Osthoff, H. D., additional, Ouyang, B., additional, Picquet-Varrault, B., additional, Platt, U., additional, Pye, H. O. T., additional, Rudich, Y., additional, Schwantes, R. H., additional, Shiraiwa, M., additional, Stutz, J., additional, Thornton, J. A., additional, Tilgner, A., additional, Williams, B. J., additional, and Zaveri, R. A., additional

Published
2016
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17. Supplementary material to "Nitrate radicals and biogenic volatile organic compounds: oxidation, mechanisms and organic aerosol"

Author

Ng, N. L., primary, Brown, S. S., additional, Archibald, A. T., additional, Atlas, E., additional, Cohen, R. C., additional, Crowley, J. N., additional, Day, D. A., additional, Donahue, N. M., additional, Fry, J. L., additional, Fuchs, H., additional, Griffin, R. J., additional, Guzman, M. I., additional, Hermann, H., additional, Hodzic, A., additional, Iinuma, Y., additional, Jimenez, J. L., additional, Kiendler-Scharr, A., additional, Lee, B. H., additional, Luecken, D. J., additional, Mao, J., additional, McLaren, R., additional, Mutzel, A., additional, Osthoff, H. D., additional, Ouyang, B., additional, Picquet-Varrault, B., additional, Platt, U., additional, Pye, H. O. T., additional, Rudich, Y., additional, Schwantes, R. H., additional, Shiraiwa, M., additional, Stutz, J., additional, Thornton, J. A., additional, Tilgner, A., additional, Williams, B. J., additional, and Zaveri, R. A., additional

Published
2016
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20. WRF-Chem model predictions of the regional impacts of N2O5 heterogeneous processes on night-time chemistry over north-western Europe

Author

Lowe, D., Archer-Nicholls, S., Morgan, W., Allan, J., Utembe, S., Ouyang, B., Aruffo, E., Le Breton, M., Zaveri, R. A., Di Carlo, P., Percival, C., Coe, H., Jones, R., McFiggans, G., Lowe, D., Archer-Nicholls, S., Morgan, W., Allan, J., Utembe, S., Ouyang, B., Aruffo, E., Le Breton, M., Zaveri, R. A., Di Carlo, P., Percival, C., Coe, H., Jones, R., and McFiggans, G.

Abstract

Chemical modelling studies have been conducted over north-western Europe in summer conditions, showing that night-time dinitrogen pentoxide (N2O5) heterogeneous reactive uptake is important regionally in modulating particulate nitrate and has a∼modest influence on oxidative chemistry. Results from Weather Research and Forecasting model with Chemistry (WRF-Chem) model simulations, run with a detailed volatile organic compound (VOC) gas-phase chemistry scheme and the Model for Simulating Aerosol Interactions and Chemistry (MOSAIC) sectional aerosol scheme, were compared with a series of airborne gas and particulate measurements made over the UK in July 2010. Modelled mixing ratios of key gas-phase species were reasonably accurate (correlations with measurements of 0.7-0.9 for NO2 and O3). However modelled loadings of particulate species were less accurate (correlation with measurements for particulate sulfate and ammonium were between 0.0 and 0.6). Sulfate mass loadings were particularly low (modelled means of 0.5-0.7 μg kg−1air, compared with measurements of 1.0-1.5 μg kg−1air). Two flights from the campaign were used as test cases - one with low relative humidity (RH) (60-70%), the other with high RH (80-90%). N2O5 heterogeneous chemistry was found to not be important in the low-RH test case; but in the high-RH test case it had a strong effect and significantly improved the agreement between modelled and measured NO3 and N2O5. When the model failed to capture atmospheric RH correctly, the modelled NO3 and N2O5 mixing ratios for these flights differed significantly from the measurements. This demonstrates that, for regional modelling which involves heterogeneous processes, it is essential to capture the ambient temperature and water vapour profiles. The night-time NO3 oxidation of VOCs across the whole region was found to be 100-300 times slower than the daytime OH oxidation of these compounds. The difference in contribution was less for alkenes (×

Published
2015

23. Supplementary material to "What do correlations tell us about anthropogenic–biogenic interactions and SOA formation in the Sacramento Plume during CARES?"

Author

Kleinman, L., primary, Kuang, C., additional, Sedlacek, A., additional, Senum, G., additional, Springston, S., additional, Wang, J., additional, Zhang, Q., additional, Jayne, J., additional, Fast, J., additional, Hubbe, J., additional, Shilling, J., additional, and Zaveri, R., additional

Published
2015
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24. WRF-Chem model predictions of the regional impacts of N<sub>2</sub>O<sub>5</sub> heterogeneous processes on night-time chemistry over north-western Europe

Author

Lowe, D., primary, Archer-Nicholls, S., additional, Morgan, W., additional, Allan, J., additional, Utembe, S., additional, Ouyang, B., additional, Aruffo, E., additional, Le Breton, M., additional, Zaveri, R. A., additional, Di Carlo, P., additional, Percival, C., additional, Coe, H., additional, Jones, R., additional, and McFiggans, G., additional

Published
2015
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26. The AeroCom evaluation and intercomparison of organic aerosol in global models

Author

Tsigaridis, K., primary, Daskalakis, N., additional, Kanakidou, M., additional, Adams, P. J., additional, Artaxo, P., additional, Bahadur, R., additional, Balkanski, Y., additional, Bauer, S. E., additional, Bellouin, N., additional, Benedetti, A., additional, Bergman, T., additional, Berntsen, T. K., additional, Beukes, J. P., additional, Bian, H., additional, Carslaw, K. S., additional, Chin, M., additional, Curci, G., additional, Diehl, T., additional, Easter, R. C., additional, Ghan, S. J., additional, Gong, S. L., additional, Hodzic, A., additional, Hoyle, C. R., additional, Iversen, T., additional, Jathar, S., additional, Jimenez, J. L., additional, Kaiser, J. W., additional, Kirkevåg, A., additional, Koch, D., additional, Kokkola, H., additional, Lee, Y. H, additional, Lin, G., additional, Liu, X., additional, Luo, G., additional, Ma, X., additional, Mann, G. W., additional, Mihalopoulos, N., additional, Morcrette, J.-J., additional, Müller, J.-F., additional, Myhre, G., additional, Myriokefalitakis, S., additional, Ng, N. L., additional, O'Donnell, D., additional, Penner, J. E., additional, Pozzoli, L., additional, Pringle, K. J., additional, Russell, L. M., additional, Schulz, M., additional, Sciare, J., additional, Seland, Ø., additional, Shindell, D. T., additional, Sillman, S., additional, Skeie, R. B., additional, Spracklen, D., additional, Stavrakou, T., additional, Steenrod, S. D., additional, Takemura, T., additional, Tiitta, P., additional, Tilmes, S., additional, Tost, H., additional, van Noije, T., additional, van Zyl, P. G., additional, von Salzen, K., additional, Yu, F., additional, Wang, Z., additional, Zaveri, R. A., additional, Zhang, H., additional, Zhang, K., additional, Zhang, Q., additional, and Zhang, X., additional

Published
2014
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27. Modeling regional aerosol and aerosol precursor variability over California and its sensitivity to emissions and long-range transport during the 2010 CalNex and CARES campaigns

Author

Fast, J. D., primary, Allan, J., additional, Bahreini, R., additional, Craven, J., additional, Emmons, L., additional, Ferrare, R., additional, Hayes, P. L., additional, Hodzic, A., additional, Holloway, J., additional, Hostetler, C., additional, Jimenez, J. L., additional, Jonsson, H., additional, Liu, S., additional, Liu, Y., additional, Metcalf, A., additional, Middlebrook, A., additional, Nowak, J., additional, Pekour, M., additional, Perring, A., additional, Russell, L., additional, Sedlacek, A., additional, Seinfeld, J., additional, Setyan, A., additional, Shilling, J., additional, Shrivastava, M., additional, Springston, S., additional, Song, C., additional, Subramanian, R., additional, Taylor, J. W., additional, Vinoj, V., additional, Yang, Q., additional, Zaveri, R. A., additional, and Zhang, Q., additional

Published
2014
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28. Supplementary material to "WRF-chem model predictions of the regional impacts of N2O5 heterogeneous processes on nighttime chemistry over north-western Europe"

Author

Lowe, D., primary, Archer-Nicholls, S., additional, Morgan, W., additional, Allan, J., additional, Utembe, S., additional, Ouyang, B., additional, Aruffo, E., additional, Le Breton, M., additional, Zaveri, R. A., additional, Di Carlo, P., additional, Percival, C., additional, Coe, H., additional, Jones, R., additional, and McFiggans, G., additional

Published
2014
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29. WRF-chem model predictions of the regional impacts of N2O5 heterogeneous processes on nighttime chemistry over north-western Europe

Author

Lowe, D., primary, Archer-Nicholls, S., additional, Morgan, W., additional, Allan, J., additional, Utembe, S., additional, Ouyang, B., additional, Aruffo, E., additional, Le Breton, M., additional, Zaveri, R. A., additional, Di Carlo, P., additional, Percival, C., additional, Coe, H., additional, Jones, R., additional, and McFiggans, G., additional

Published
2014
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32. Modeling regional aerosol variability over California and its sensitivity to emissions and long-range transport during the 2010 CalNex and CARES campaigns

Author

Fast, J. D., primary, Allan, J., additional, Bahreini, R., additional, Craven, J., additional, Emmons, L., additional, Ferrare, R., additional, Hayes, P. L., additional, Hodzic, A., additional, Holloway, J., additional, Hostetler, C., additional, Jimenez, J. L., additional, Jonsson, H., additional, Liu, S., additional, Liu, Y., additional, Metcalf, A., additional, Middlebrook, A., additional, Nowak, J., additional, Pekour, M., additional, Perring, A., additional, Russell, L., additional, Sedlacek, A., additional, Seinfeld, J., additional, Setyan, A., additional, Shilling, J., additional, Shrivastava, M., additional, Springston, S., additional, Song, C., additional, Subramanian, R., additional, Taylor, J. W., additional, Vinoj, V., additional, Yang, Q., additional, Zaveri, R. A., additional, and Zhang, Q., additional

Published
2014
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33. Supplementary material to "Modeling regional aerosol variability over California and its sensitivity to emissions and long-range transport during the 2010 CalNex and CARES campaigns"

Author

Fast, J. D., primary, Allan, J., additional, Bahreini, R., additional, Craven, J., additional, Emmons, L., additional, Ferrare, R., additional, Hayes, P. L., additional, Hodzic, A., additional, Holloway, J., additional, Hostetler, C., additional, Jimenez, J. L., additional, Jonsson, H., additional, Liu, S., additional, Liu, Y., additional, Metcalf, A., additional, Middlebrook, A., additional, Nowak, J., additional, Pekour, M., additional, Perring, A., additional, Russell, L., additional, Sedlacek, A., additional, Seinfeld, J., additional, Setyan, A., additional, Shilling, J., additional, Shrivastava, M., additional, Springston, S., additional, Song, C., additional, Subramanian, R., additional, Taylor, J. W., additional, Vinoj, V., additional, Yang, Q., additional, Zaveri, R. A., additional, and Zhang, Q., additional

Published
2014
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34. Supplementary material to "The AeroCom evaluation and intercomparison of organic aerosol in global models"

Author

Tsigaridis, K., primary, Daskalakis, N., additional, Kanakidou, M., additional, Adams, P. J., additional, Artaxo, P., additional, Bahadur, R., additional, Balkanski, Y., additional, Bauer, S. E., additional, Bellouin, N., additional, Benedetti, A., additional, Bergman, T., additional, Berntsen, T. K., additional, Beukes, J. P., additional, Bian, H., additional, Carslaw, K. S., additional, Chin, M., additional, Curci, G., additional, Diehl, T., additional, Easter, R. C., additional, Ghan, S. J., additional, Gong, S. L., additional, Hodzic, A., additional, Hoyle, C. R., additional, Iversen, T., additional, Jathar, S., additional, Jimenez, J. L., additional, Kaiser, J. W., additional, Kirkevåg, A., additional, Koch, D., additional, Kokkola, H., additional, Lee, Y. H., additional, Lin, G., additional, Liu, X., additional, Luo, G., additional, Ma, X., additional, Mann, G. W., additional, Mihalopoulos, N., additional, Morcrette, J.-J., additional, Müller, J.-F., additional, Myhre, G., additional, Myriokefalitakis, S., additional, Ng, S., additional, O'Donnell, D., additional, Penner, J. E., additional, Pozzoli, L., additional, Pringle, K. J., additional, Russell, L. M., additional, Schulz, M., additional, Sciare, J., additional, Seland, Ø., additional, Shindell, D. T., additional, Sillman, S., additional, Skeie, R. B., additional, Spracklen, D., additional, Stavrakou, T., additional, Steenrod, S. D., additional, Takemura, T., additional, Tiitta, P., additional, Tilmes, S., additional, Tost, H., additional, van Noije, T., additional, van Zyl, P. G., additional, von Salzen, K., additional, Yu, F., additional, Wang, Z., additional, Zaveri, R. A., additional, Zhang, H., additional, Zhang, K., additional, Zhang, Q., additional, and Zhang, X., additional

Published
2014
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39. Toward a minimal representation of aerosols in climate models : description and evaluation in the Community Atmosphere Model CAM5

Author

Liu, X., Easter, R. C., Ghan, S. J., Zaveri, R., Rasch, P., Shi, X., Lamarque, J. -F, Gettelman, A., Morrison, H., Vitt, F., Conley, A., Park, S., Neale, R., Hannay, C., Ekman, Annica, Hess, P., Mahowald, N., Collins, W., Iacono, M. J., Bretherton, C. S., Flanner, M. G., Mitchell, D., Liu, X., Easter, R. C., Ghan, S. J., Zaveri, R., Rasch, P., Shi, X., Lamarque, J. -F, Gettelman, A., Morrison, H., Vitt, F., Conley, A., Park, S., Neale, R., Hannay, C., Ekman, Annica, Hess, P., Mahowald, N., Collins, W., Iacono, M. J., Bretherton, C. S., Flanner, M. G., and Mitchell, D.

Abstract

A modal aerosol module (MAM) has been developed for the Community Atmosphere Model version 5 (CAM5), the atmospheric component of the Community Earth System Model version 1 (CESM1). MAM is capable of simulating the aerosol size distribution and both internal and external mixing between aerosol components, treating numerous complicated aerosol processes and aerosol physical, chemical and optical properties in a physically-based manner. Two MAM versions were developed: a more complete version with seven lognormal modes (MAM7), and a version with three lognormal modes (MAM3) for the purpose of long-term (decades to centuries) simulations. In this paper a description and evaluation of the aerosol module and its two representations are provided. Sensitivity of the aerosol lifecycle to simplifications in the representation of aerosol is discussed. Simulated sulfate and secondary organic aerosol (SOA) mass concentrations are remarkably similar between MAM3 and MAM7. Differences in primary organic matter (POM) and black carbon (BC) concentrations between MAM3 and MAM7 are also small (mostly within 10 %). The mineral dust global burden differs by 10 % and sea salt burden by 30-40 % between MAM3 and MAM7, mainly due to the different size ranges for dust and sea salt modes and different standard deviations of the log-normal size distribution for sea salt modes between MAM3 and MAM7. The model is able to qualitatively capture the observed geographical and temporal variations of aerosol mass and number concentrations, size distributions, and aerosol optical properties. However, there are noticeable biases; e.g., simulated BC concentrations are significantly lower than measurements in the Arctic. There is a low bias in modeled aerosol optical depth on the global scale, especially in the developing countries. These biases in aerosol simulations clearly indicate the need for improvements of aerosol processes (e.g., emission fluxes of anthropogenic aerosols and precursor gases in de, AuthorCount:22

Published
2012
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42. Evolution of multispectral aerosol optical properties in a biogenically-influenced urban environment during the CARES campaign

Author

Gyawali, M., primary, Arnott, W. P., additional, Zaveri, R. A., additional, Song, C., additional, Pekour, M., additional, Flowers, B., additional, Dubey, M. K., additional, Setyan, A., additional, Zhang, Q., additional, Harworth, J. W., additional, Radney, J. G., additional, Atkinson, D. B., additional, China, S., additional, Mazzoleni, C., additional, Gorkowski, K., additional, Subramanian, R., additional, Jobson, B. T., additional, and Moosmüller, H., additional

Published
2013
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44. Enhanced SOA formation from mixed anthropogenic and biogenic emissions during the CARES campaign

Author

Shilling, J. E., primary, Zaveri, R. A., additional, Fast, J. D., additional, Kleinman, L., additional, Alexander, M. L., additional, Canagaratna, M. R., additional, Fortner, E., additional, Hubbe, J. M., additional, Jayne, J. T., additional, Sedlacek, A., additional, Setyan, A., additional, Springston, S., additional, Worsnop, D. R., additional, and Zhang, Q., additional

Published
2013
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46. Enhanced SOA formation from mixed anthropogenic and biogenic emissions during the CARES campaign

Author

Shilling, J. E., primary, Zaveri, R. A., additional, Fast, J. D., additional, Kleinman, L., additional, Alexander, M. L., additional, Canagaratna, M. R., additional, Fortner, E., additional, Hubbe, J. M., additional, Jayne, J. T., additional, Sedlacek, A., additional, Setyan, A., additional, Springston, S., additional, Worsnop, D. R., additional, and Zhang, Q., additional

Published
2012
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47. Characterization of submicron particles influenced by mixed biogenic and anthropogenic emissions using high-resolution aerosol mass spectrometry: results from CARES

Author

Setyan, A., primary, Zhang, Q., additional, Merkel, M., additional, Knighton, W. B., additional, Sun, Y., additional, Song, C., additional, Shilling, J. E., additional, Onasch, T. B., additional, Herndon, S. C., additional, Worsnop, D. R., additional, Fast, J. D., additional, Zaveri, R. A., additional, Berg, L. K., additional, Wiedensohler, A., additional, Flowers, B. A., additional, Dubey, M. K., additional, and Subramanian, R., additional

Published
2012
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