References

ACP

Atmospheric Chemistry and Physics

ACP

1680-7324

Copernicus GmbH

Göttingen, Germany

10.5194/acp-9-6727-2009

Aerosol optical properties relevant to regional remote sensing of CCN activity and links to their organic mass fraction: airborne observations over Central Mexico and the US West Coast during MILAGRO/INTEX-B

Shinozuka

¹ ⁷ Clarke

A. D.

¹ DeCarlo

P. F.

² ³ ⁸ Jimenez

J. L.

² ⁴ Dunlea

E. J.

² Roberts

G. C.

⁵ Tomlinson

J. M.

⁶ ⁹ Collins

D. R.

⁶ Howell

S. G.

¹ Kapustin

V. N.

¹ McNaughton

C. S.

¹ Zhou

School of Ocean and Earth Science and Technology, University of Hawaii, Honolulu, HI, USA

Cooperative Institute for Research in the Environmental Sciences, University of Colorado, Boulder, CO, USA

Dept. of Atmospheric and Oceanic Sciences, University of Colorado, Boulder, CO, USA

Dept. of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA

Center for Atmospheric Sciences, Scripps Institution of Oceanography, La Jolla, CA, USA

Department of Atmospheric Sciences, Texas A&M University, College Station, TX, USA

now at: NASA Postdoctoral Program, NASA Ames Research Center, MS 245-5, Moffett Field, CA, USA

now at: Paul Scherrer Institut, 5232 Villigen-PSI, Switzerland

now at: Pacific Northwest National Laboratory, Richland, WA, USA

17 09 2009

9 18 6727 6742

This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

This article is available from http://www.atmos-chem-phys.net/9/6727/2009/acp-9-6727-2009.html

The full text article is available as a PDF file from http://www.atmos-chem-phys.net/9/6727/2009/acp-9-6727-2009.pdf

Remote sensing of cloud condensation nuclei (CCN) would help evaluate the indirect effects of tropospheric aerosols on clouds and climate. To assess its feasibility, we examined relationships of submicron aerosol composition to CCN activity and optical properties observed during the MILAGRO/INTEX-B aircraft campaigns. An indicator of CCN activity, κ, was calculated from hygroscopicity measured under saturation. κ for dry 100 nm particles decreased with increasing organic fraction of non-refractory mass of submicron particles (OMF) as 0.34–0.20×OMF over Central Mexico and 0.47–0.43×OMF over the US West Coast. These fits represent the critical dry diameter, centered near 100 nm for 0.2% supersaturation but varied as κ<sup>(−1/3)</sup>, within measurement uncertainty (~20%). The decreasing trends of CCN activity with the organic content, evident also in our direct CCN counts, were consistent with previous ground and laboratory observations of highly organic particles. The wider range of OMF, 0–0.8, for our research areas means that aerosol composition will be more critical for estimation of CCN concentration than at the fixed sites previously studied. Furthermore, the wavelength dependence of extinction was anti-correlated with OMF as −0.70×OMF+2.0 for Central Mexico's urban and industrial pollution air masses, for unclear reasons. The Angstrom exponent of absorption increased with OMF, more rapidly under higher single scattering albedo, as expected for the interplay between soot and colored weak absorbers (some organic species and dust). Because remote sensing products currently use the wavelength dependence of extinction albeit in the column integral form and may potentially include that of absorption, these regional spectral dependencies are expected to facilitate retrievals of aerosol bulk chemical composition and CCN activity over Central Mexico.

References 1

Aiken, A. C., DeCarlo, P. F., and Jimenez, J. L.: Elemental Analysis of Organic Species with Electron Ionization High-Resolution Mass Spectrometry, Anal. Chem., 79, 8350–8358, 2007.

Aiken, A. C., DeCarlo, P. F., Kroll, J. H., Worsnop, D. R., et al.: O/C and OM/OC Ratios of Primary, Secondary, and Ambient Organic Aerosols with High Resolution Time-of-Flight Aerosol Mass Spectrometry , Environ. Sci. Technol., 42, 4478–4485, 2008.

Aiken, A. C., Salcedo, D., Cubison, M. J., Huffman, J. A., DeCarlo, P. F., Ulbrich, I. M., Docherty, K. S., Sueper, D., Kimmel, J. R., Worsnop, D. R., Trimborn, A., Northway, M., Stone, E. A., Schauer, J. J., Volkamer, R., Fortner, E., de Foy, B., Wang, J., Laskin, A., Shutthanandan, V., Zheng, J., Zhang, R., Gaffney, J., Marley, N. A., Paredes-Miranda, G., Arnott, W. P., Molina, L. T., Sosa, G., and Jimenez, J. L.: Mexico City aerosol analysis during MILAGRO using high resolution aerosol mass spectrometry at the urban supersite (T0) - Part~1: Fine particle composition and organic source apportionment, Atmos. Chem. Phys. Discuss., 9, 8377–8427, 2009.

Albrecht, B. A.: Aerosols, cloud microphysics, and fractional cloudiness, Science, 245, 1227–1230, 1989.

Allan, J. D., Coe, H., Bower, K. N., et al.: Technical note: Extraction of chemically resolved mass spectra from Aerodyne aerosol mass spectrometer data, J. Aerosol Sci., 35, 909–922, 2004.

An, W. J., Pathak, R. K., Lee, B. H., and Pandis, S. N.: Aerosol volatility measurement using an improved thermodenuder: Application to secondary organic aerosol, J. Aerosol Sci., 38, 305–314, doi:10.1016/j.jaerosci.2006.12.002, 2007.

Anderson, T. L., Covert, D. S., Marshall, S. F., Laucks, M. L., Charlson, R. J., Waggoner, A. P., Ogren, J. A., Caldow, R., Holm, R. L., Quant, F. R., Sem, G. J., Wiedensohler, A., Ahlquist, N. A., and Bates, T. S.: Performance characteristics of a high-sensitivity, three-wavelength, total scatter/backscatter nephelometer, J. Atmos. Ocean. Tech., 13, 967–986, 1996.

Anderson, T. L., Masonis, S. J., Covert, D. S., Ahlquist, N. C., Howell, S. G., Clarke, A. D., and McNaughton, C. S.: Variability of aerosol optical properties derived from in situ aircraft measurements during ACE-Asia, J. Geophys. Res., 108(D23), 8647, doi:10.1029/2002JD003247, 2003.

Anderson, T. L., Wu, Y. H., Chu, D. A., Schmid, B., Redemann, J., and Dubovik, O.: Testing the MODIS satellite retrieval of aerosol fine-mode fraction, J. Geophys. Res.-Atmos., 110(D18), D18204, doi:10.1029/2005JD005978, 2005.

Andreae, M. O.: Correlation between cloud condensation nuclei concentration and aerosol optical thickness in remote and polluted regions, Atmos. Chem. Phys., 9, 543–556, 2009.

Barnard, J. C., Volkamer, R., and Kassianov, E. I.: Estimation of the mass absorption cross section of the organic carbon component of aerosols in the Mexico City Metropolitan Area, Atmos. Chem. Phys., 8, 6665–6679, 2008.

Bergstrom, R. W., Russell, P. B., and Hignett, P.: Wavelength dependence of the absorption of black carbon particles: Predictions and results from the TARFOX experiment and implications for the aerosol single scattering albedo, J. Atmos. Sci., 59(3), 567–577, 2002.

Bond, T. C., Anderson, T. L., and Campbell, D.: Calibration and intercomparison of filter-based measurements of visible light absorption by aerosols, Aerosol Sci. Tech., 30, 582–600, 1999.

Bougiatioti, A., Fountoukis, C., Kalivitis, N., Pandis, S. N., Nenes, A., and Mihalopoulos, N.: Cloud condensation nuclei measurements in the eastern Mediterranean marine boundary layer: CCN closure and droplet growth kinetics, Atmos. Chem. Phys. Discuss., 9, 10303–10336, 2009.

Canagaratna, M. R., Jayne, J. T., Jimenez, J. L., et al.: Chemical and Microphysical Characterization of Ambient Aerosols with the Aerodyne Aerosol Mass Spectrometer, Mass Spectrom. Rev., 26, 185–222, 2007.

Cappa, C. D., Lack, D. A., Burkholder, J. B., and Ravishankara, A. R.: Bias in filter based aerosol light absorption measurements due to organic aerosol loading: Evidence from laboratory measurements, Aerosol Sci. Tech., 42(12), 1022–1032, 2008.

Clarke, A. D.: A thermo-optic technique for in situ analysis of size-resolved aerosol physicochemistry, Atmos. Environ., 25A, 635–644, 1991.

Clarke, A. D., Varner, J. L., Eisele, F., Mauldin, R. L., Tanner, D., and Litchy, M.: Particle production in the remote marine atmosphere: Cloud outflow and subsidence during ACE~1, J. Geophys. Res., 103(D13), 16397–16409, 1998.

Corr, C. A., Krotkov, N., Madronich, S., Slusser, J. R., Holben, B., Gao, W., Flynn, J., Lefer, B., and Kreidenweis, S. M.: Retrieval of aerosol single scattering albedo at ultraviolet wavelengths at the T1 site during MILAGRO, Atmos. Chem. Phys., 9, 5813–5827, 2009.

Cubison, M. J., Ervens, B., Feingold, G., Docherty, K. S., Ulbrich, I. M., Shields, L., Prather, K., Hering, S., and Jimenez, J. L.: The influence of chemical composition and mixing state of Los Angeles urban aerosol on CCN number and cloud properties, Atmos. Chem. Phys., 8, 5649–5667, 2008.

DeCarlo, P., Slowik, J. G., Worsnop, D. R., Davidovits, P., and Jimenez, J. L.: Particle Morphology and Density Characterization by Combined Mobility and Aerodynamic Diameter Measurements, Part~1: Theory, Aerosol Sci. Tech., 38, 1185–1205, doi:10.1080/027868290903907, 2004.

DeCarlo, P. F., Dunlea, E. J., Kimmel, J. R., Aiken, A. C., Sueper, D., Crounse, J., Wennberg, P. O., Emmons, L., Shinozuka, Y., Clarke, A., Zhou, J., Tomlinson, J., Collins, D. R., Knapp, D., Weinheimer, A. J., Montzka, D. D., Campos, T., and Jimenez, J. L.: Fast airborne aerosol size and chemistry measurements above Mexico City and Central Mexico during the MILAGRO campaign, Atmos. Chem. Phys., 8, 4027–4048, 2008.

DeCarlo, P. F., Kimmel, J. R., Trimborn, A., Northway, M. J., Jayne, J. T., Aiken, A. C., Gonin, M., Fuhrer, K., Horvath, T., Docherty, K. S., Worsnop, D. R., and Jimenez, J. L.: Field-Deployable, High-Resolution, Time-of-Flight Aerosol Mass Spectrometer, Anal. Chem., 78(24), 8281–8289, 2006.

Dunlea, E. J., DeCarlo, P. F., Aiken, A. C., Kimmel, J. R., Peltier, R. E., Weber, R. J., Tomlison, J., Collins, D. R., Shinozuka, Y., McNaughton, C. S., Howell, S. G., Clarke, A. D., Emmons, L. K., Apel, E. C., Pfister, G. G., van Donkelaar, A., Martin, R. V., Millet, D. B., Heald, C. L., and Jimenez, J. L.: Evolution of Asian aerosols during transpacific transport in INTEX-B, Atmos. Chem. Phys. Discuss., 8, 15375–15461, 2008.

Dusek, U., Frank, G. P., Hildebrandt, L., et al.: Size Matters More Than Chemistry for Cloud-Nucleating Ability of Aerosol Particles, Science, 312, 1375–1378, 2006.

Ervens, B., Cubison, M., Andrews, E., Feingold, G., Ogren, J. A., Jimenez, J. L., DeCarlo, P., and Nenes, A.: Prediction of CCN number concentration using Measurements of Aerosol Size Distributions and Composition and Light Scattering Enhancement due to Humidity. J. Geophys. Res.-Atmos., 112, D10S32, doi:10.1029/2006JD007426, 2007.

Facchini, M. C., Mircea, M., Sandro, F., and Charlson, R.J.: Cloud albedo enhancement by surface-active organic solutes in growing droplets, Nature, 401(6750), 257–259, 1999.

Faulhaber, A. E., Thomas, B. M., Jimenez, J. L., et al. : Characterization of a Thermodenuder-Particle Beam Mass Spectrometer System for the Study of Organic Aerosol Volatility and Composition, Atmos. Meas. Tech., 2, 15–31, 2009.

Garland, R. M., Yang, H., Schmid, O., Rose, D., Nowak, A., Achtert, P., Wiedensohler, A., Takegawa, N., Kita, K., Miyazaki, Y., Kondo, Y., Hu, M., Shao, M., Zeng, L. M., Zhang, Y. H., Andreae, M. O., and Pöschl, U.: Aerosol optical properties in a rural environment near the mega-city Guangzhou, China: implications for regional air pollution, radiative forcing and remote sensing, Atmos. Chem. Phys., 8, 5161–5186, 2008.

Gasparini, R., Li, R., and Collins, D. R.: Integration of size distributions and size-resolved hygroscopicity measured during the Houston Supersite for compositional categorization of the aerosol, Atmos. Environ., 38(20), 3285–3303, 2004.

Gunthe, S. S., King, S. M., Rose, D., Chen, Q., Roldin, P., Farmer, D. K., Jimenez, J. L., Artaxo, P., Andreae, M. O., Martin, S. T., and Pöschl, U.: Cloud condensation nuclei in pristine tropical rainforest air of Amazonia: size-resolved measurements and modeling of atmospheric aerosol composition and CCN activity, Atmos. Chem. Phys. Discuss., 9, 3811–3870, 2009.

Hartz, K. E. H., Tischuk, J. E., Chan, M. N., Donahue, C. K. C. N. M., and Pandis, S. N.: Cloud condensation nuclei activation of limited solubility organic aerosol, Atmos. Environ., 40(4), 605–617, 2006.

Heald, C. L., Goldstein, A. H., Allan, J. D., Aiken, A. C., Apel, E., Atlas, E. L., Baker, A. K., Bates, T. S., Beyersdorf, A. J., Blake, D. R., Campos, T., Coe, H., Crounse, J. D., DeCarlo, P. F., de Gouw, J. A., Dunlea, E. J., Flocke, F. M., Fried, A., Goldan, P., Griffin, R. J., Herndon, S. C., Holloway, J. S., Holzinger, R., Jimenez, J. L., Junkermann, W., Kuster, W. C., Lewis, A. C., Meinardi, S., Millet, D. B., Onasch, T., Polidori, A., Quinn, P. K., Riemer, D. D., Roberts, J. M., Salcedo, D., Sive, B., Swanson, A. L., Talbot, R., Warneke, C., Weber, R. J., Weibring, P., Wennberg, P. O., Worsnop, D. R., Wittig, A. E., Zhang, R., Zheng, J., and Zheng, W.: Total observed organic carbon (TOOC) in the atmosphere: a synthesis of North American \mboxobservations, Atmos. Chem. Phys., 8, 2007–2025, 2008.

Heintzenberg, J. and Charlson, R. J.: Design and Applications of the Integrating Nephelometer: A Review, J. Atmos. Ocean. Tech., 13, 987–1000, 1996.

Hoppel, W. A., Frick, G. M., and Fitzgerald, J. W.: Deducing droplet concentration and supersaturation in marine boundary layer clouds from surface aerosol measurements, J. Geophys. Res., 101(D21), 26553–26565, 1996.

Hudson, J. G. and Svensson, G.: Cloud Microphysical \mboxRelationships in California Marine Stratus, J. Appl. Meteorol., 34(12), 2655–2666, 1995.

Huffman, J. A., Ziemann, P. J., Jayne, J. T., Worsnop, D. R., and Jimenez, J. L.: Development and Characterization of a Fast-Stepping/Scanning Thermodenuder for Chemically-Resolved Aerosol Volatility Measurements, Aerosol Sci. Tech.., 42, 395–407, 2008.

Jimenez, J. L., Jayne, J. T., Shi, Q., et al.: Ambient Aerosol Sampling with an Aerosol Mass Spectrometer, J. Geophys. Res., 108, 8425, doi:8410.1029/2001JD001213, 2003.

Kahn, R. A., Gaitley, B. J., Martonchik, J. V., et al.: Multiangle Imaging Spectroradiometer (MISR) global aerosol optical depth validation based on 2 years of coincident Aerosol Robotic Network (AERONET) observations, J. Geophys. Res., 110, D10S04, doi:10.1029/2004JD004706, 2005.

Kanakidou, M., Seinfeld, J. H., Pandis, S. N., Barnes, I., Dentener, F. J., Facchini, M. C., Van Dingenen, R., Ervens, B., Nenes, A., Nielsen, C. J., Swietlicki, E., Putaud, J. P., Balkanski, Y., Fuzzi, S., Horth, J., Moortgat, G. K., Winterhalter, R., Myhre, C. E. L., Tsigaridis, K., Vignati, E., Stephanou, E. G., and Wilson, J.: Organic aerosol and global climate modelling: a review, Atmos. Chem. Phys., 5, 1053–1123, 2005.

King, S. M., Rosenoern, T., Shilling, J. E., Chen, Q., and Martin, S. T.:, Cloud condensation nucleus activity of secondary organic aerosol particles mixed with sulfate, Geophys. Res. Lett., 34, L24806, doi:10.1029/2007GL030390, 2007.

Kinne, S.: Climatologies of Cloud-related Aerosols: Part~1: Particle number and size, edited by: Heintzenberg, J. and Charlson, R. J.,Cambridge, MA, The MIT Press, ISBN 978-0-262-012874, 37–57, 2009.

Kirchstetter, T. W., Novakov, T., and Hobbs, P. V.: Evidence that the spectral dependence of light absorption by aerosols is affected by organic carbon, J. Geophys. Res., 109, D21208, doi:10.1029/2004JD004999, 2004.

Kline, J., Huebert, B., Howell, S., Blomquist, B., Zhuang, J., Bertram, T., and Carrillo, J.: Aerosol composition and size versus altitude measured from the C-130 during ACE-Asia, J. Geophys. Res., 109, D19S08, doi:10.1029/2004JD004540, 2004.

Kuwata, M., Kondo, Y., Miyazaki, Y., Komazaki, Y., Kim, J. H., Yum, S. S., Tanimoto, H., and Matsueda, H.: Cloud condensation nuclei activity at Jeju Island, Korea in spring 2005, Atmos. Chem. Phys., 8, 2933–2948, 2008.

Lance, S., Medina, J., Smith, J., and Nenes, A.: Mapping the Operation of the DMT Continuous Flow CCN Counter, Aerosol Sci. Tech., 40, 242–254, 2006.

McNaughton, C. S., Clarke, A. D., Howell, S. G., Pinkerton, M., Anderson, B. E., Thornhill, K. L., Winstead, E. L., Hudgins, C. H., Dibb, J. E., Scheuer, E., and Maring, H.: Results from the DC-8 inlet characterization experiment (DICE): Airborne versus surface sampling of mineral dust and sea salt aerosols, Aerosol Sci. Tech., 41(2), 136-159, 2007.

McNaughton, C. S., Clarke, A. D., Kapustin, V., Shinozuka, Y., Howell, S. G., Anderson, B. E., Winstead, E., Dibb, J., Scheuer, E., Cohen, R. C., Wooldridge, P., Perring, A., Huey, L. G., Kim, S., Jimenez, J. L., Dunlea, E. J., DeCarlo, P. F., Wennberg, P. O., Crounse, J. D., Weinheimer, A. J., and Flocke, F.: Observations of heterogeneous reactions between Asian pollution and mineral dust over the Eastern North Pacific during INTEX-B, Atmos. Chem. Phys. Discuss., 9, 8469–8539, 2009.

Molina, L. T., Madronich, S., Gaffney, J., et al.: An Overview of MILAGRO 2006 Campaign: Mexico City Emissions and its Transport and Transformation, submitted to Atmos. Chem. Phys. Discuss., 2009.

Nenes, A., Charlson, R. J., Facchini, M. C., Kulmala, M., Laaksonen, A., and Seinfeld, J. H.: Can chemical effects on cloud droplet number rival the first indirect effect?, Geophys. Res. Lett., 29(17), 1848, doi:10.1029/2002GL015295, 2002.

Petters, M. D. and Kreidenweis, S. M.: A single parameter representation of hygroscopic growth and cloud condensation nucleus activity, Atmos. Chem. Phys., 7, 1961–1971, 2007.

Pöschl, U., Rose, D. and Andreae, M. O.: Climatologies of Cloud-related Aerosols: Part~2: Particle Hygroscopicity and Cloud Condensation Nuclei Activity, edited by: Heintzenberg, J. and Charlson, R. J., Cambridge, MA, The MIT Press, ISBN 978-0-262-012874, 2009.

Pruppacher, H. R., and Klett, J. D.: Microphysics of Clouds and Precipitation, 1980.

Quinn, P. K., Bates, T. S., Baynard, T., et al.: Impact of particulate organic matter on the relative humidity dependence of light scattering: A simplified parameterization, Geophys. Res. Lett., 32, L22809, doi:22810.21029/22005GL024322, 2005.

Raymond, T. M. and Pandis, S. N.: Cloud activation of single-component organic aerosol particles, J. Geophys. Res., 107(D24), 4787, doi:10.1029/2002JD002159, 2002.

Remer, L. A., Kaufman, Y. J., Tanré, D., et al.: The MODIS Aerosol Algorithm, Products, and Validation, J. Atmos. Sci., 62, 947–973, 2006.

Roberts, G. C. and Nenes, A.: A Continuous-Flow Streamwise Thermal-Gradient CCN Chamber for Atmospheric Measurements, Aerosol Sci. Tech., 39, 206–221, 2005.

Rogers, R. R., Hair, J. W., Hostetler, C. A., Ferrare, R. A., Obland, M. D., Cook, A. L., Harper, D. B., Burton, S. P., Shinozuka, Y., McNaughton, C. S., Clarke, A. D., Redemann, J., Russell, P. B., Livingston, J. M., and Kleinman, L. I.: NASA LaRC airborne high spectral resolution lidar aerosol measurements during MILAGRO: observations and validation, Atmos. Chem. Phys., 9, 4811–4826, 2009.

Rose, D., Gunthe, S. S., Mikhailov, E., Frank, G. P., Dusek, U., Andreae, M. O., and Pöschl, U.: Calibration and measurement uncertainties of a continuous-flow cloud condensation nuclei counter (DMT-CCNC): CCN activation of ammonium sulfate and sodium chloride aerosol particles in theory and experiment, Atmos. Chem. Phys., 8, 1153–1179, 2008a.

Rose, D., Nowak, A., Achtert, P., Wiedensohler, A., Hu, M., Shao, M., Zhang, Y., Andreae, M. O., and Pöschl, U.: Cloud condensation nuclei in polluted air and biomass burning smoke near the mega-city Guangzhou, China - Part~1: Size-resolved measurements and implications for the modeling of aerosol particle hygroscopicity and CCN activity, Atmos. Chem. Phys. Discuss., 8, 17343–17392, 2008b.

Shinozuka, Y., Clarke, A. D., Howell, S. G., Kapustin, V. N., McNaughton, C. S., Zhou, J., and Anderson, B. E.: Aircraft profiles of aerosol microphysics and optical properties over North America: Aerosol optical depth and its association with PM$_2.5$ and water uptake, J. Geophys. Res., 112, D12S20, doi:10.1029/2006JD007918, 2007.

Shulman, M. L., Jacobson, M. C., Carlson, R. J., Synovec, R. E., and Young, T. E.: Dissolution behavior and surface tension \mboxeffects of organic compounds in nucleating cloud droplets, Geophys. Res. Lett., 23(3), 277–280, 1996.

Singh, H. B., Brune, W. H., Crawford, J. H., Jacob, D. J., and Russell, P. B.: Overview of the summer 2004 Intercontinental Chemical Transport Experiment – North America (INTEX-A), J. Geophys. Res., 111, D24S01, doi:10.1029/2006JD007905, 2006.

Singh, H. B., Brune, W. H., Crawford, J. H., Flocke, F., and Jacob, D. J.: Chemistry and transport of pollution over the Gulf of Mexico and the Pacific: spring 2006 INTEX-B campaign overview and first results, Atmos. Chem. Phys., 9, 2301–2318, 2009.

Sorooshian, A., Murphy, S. M., Hersey, S., Gates, H., Padro, L. T., Nenes, A., Brechtel, F. J., Jonsson, H., Flagan, R. C., and Seinfeld, J. H.: Comprehensive airborne characterization of aerosol from a major bovine source, Atmos. Chem. Phys., 8, 5489–5520, 2008.

Stroud, C. A., Nenes, A., Jimenez, J. L., DeCarlo, P. F., Huffman, J. A., Bruintjes, R., Nemitz, E., Delia, A. E., Toohey, D. W., Guenther, A. B., and Nandi, S.: Cloud Activating Properties of Aerosol Observed during CELTIC, J. Atmos. Sci., 64(2), 441–459, 2007.

Subramanian, R., Kok, G. L., Baumgardner, D., Clarke, A., Shinozuka, Y., Campos, T. L., Heizer, C. G., and Stephens, B. B.: Black carbon over Mexico: the effect of atmospheric transport on mixing state, mass absorption cross-section, and BC/CO ratios, Atmos. Chem. Phys. Discuss., 9, 9081–9115, 2009.

Tomlinson, J.M., Li, R., and Collins, D. R.: Physical and chemical properties of the aerosol within the southeastern Pacific marine boundary layer, J. Geophys. Res., 112, D12211, doi:10.1029/2006JD007771, 2007.

Twomey, S.: Pollution and the planetary albedo, Atmos. Environ., 8, 1251–1256, 1974.

Ulbrich, I. M., Canagaratna, M. R., Zhang, Q., Worsnop, D. R., and Jimenez, J. L.: Interpretation of organic components from Positive Matrix Factorization of aerosol mass spectrometric data, Atmos. Chem. Phys., 9, 2891–2918, 2009.

van Donkelaar, A., Martin, R. V., Leaitch, W. R., Macdonald, A. M., Walker, T. W., Streets, D. G., Zhang, Q., Dunlea, E. J., Jimenez, J. L., Dibb, J. E., Huey, L. G., Weber, R., and Andreae, M. O.: Analysis of aircraft and satellite measurements from the Intercontinental Chemical Transport Experiment (INTEX-B) to quantify long-range transport of East Asian sulfur to Canada, Atmos. Chem. Phys., 8, 2999–3014, 2008.

Virkkula, A., Ahlquist, N. C., Covert, D. S., Arnott, W. P., Sheridan, P. J., Quinn, P. K., and Coffman, D. J.: Modification, Calibration and a Field Test of an Instrument for Measuring Light Absorption by Particles, Aerosol Sci. Tech., 39(1), 68-83, 2005.

Wang, J., Lee, Y.-N., Daum, P. H., Jayne, J., and Alexander, M. L.: Effects of aerosol organics on cloud condensation nucleus (CCN) concentration and first indirect aerosol effect, Atmos. Chem. Phys., 8, 6325–6339, 2008.

Yokelson, R. J., Crounse, J. D., DeCarlo, P. F., Karl, T., Urbanski, S., Atlas, E., Campos, T., Shinozuka, Y., Kapustin, V., Clarke, A. D., Weinheimer, A., Knapp, D. J., Montzka, D. D., Holloway, J., Weibring, P., Flocke, F., Zheng, W., Toohey, D., Wennberg, P. O., Wiedinmyer, C., Mauldin, L., Fried, A., Richter, D., Walega, J., Jimenez, J. L., Adachi, K., Buseck, P. R., Hall, S. R., and Shetter, R.: Emissions from biomass burning in the Yucatan, Atmos. Chem. Phys., 9, 5785–5812, 2009.

Zhang, D., Shi, G.-Y., Iwasaka, Y., and Hu, M.: Mixture of sulfate and nitrate in coastal atmospheric aerosols: individual particle studies in Qingdao (36°04´ N, 120°21´ E), China, Atmos. Environ., 34(17), 2669–2679, 2000.

Zhou, J.: Hygroscopic properties of atmospheric aerosol particles in various environments, Ph.D. thesis, Lund University, Lund, Sweden, ISBN 91-7874-120-3, LUTFD2/(TFKF-1025)/1-166/(2001), 166~pp., 2001.

Zhou, J., Swietlicki, E., Hansson, H. C., and Artaxo, P.: Submicrometer aerosol particle size distribution and hygroscopic growth measured in the Amazon rain forest during the wet season, J. Geophys. Res., 107(D20), 8055, doi:10.1029/2000JD000203, 2002.