Boundary layer and aerosol evolution during the 3rd Lagrangian experiment of ACE-2

Wood, R.; Johnson, D.; Osborne, S.; Andreae, M.O.; Bandy, B.; Bates, T.; O’Dowd, C.; Glantz, P.; Noone, K.; Quinn, P.; Rudolph, J.; and Suhre, K.
2000 | Tellus B Chem Phys Meteorol | 52B (239-257)

Evolution of the aerosol, cloud and boundary layer dynamic and thermodynamic characteristics during the second Lagrangian experiment of ACE-2

Osborne, S.M.; Johnson, D.W.; Wood, R.; Bandy, B.J.; Andreae, M.O.; O’Dowd, C.D.; Glantz, P.; Noone, K.; Gerbig, C.; Rudolph, J.; Bates, T.S.; and Quinn, P
2000 | Tellus B Chem Phys Meteorol | 52B (375-400)

Observations of the evolution of the aerosol, cloud and boundary layer characteristics during the 1st ACE-2 Lagrangian experiment

Johnson, D.W; Osborne, S.; Wood, R.; Suhre, K.; Quinn, P.K.; Bates, T.S.; Andreae, M.O.; Noone, K.; Glantz, P.; Bandy , B.; Rudolph, J.; and, O’Dowd
2000 | Tellus B Chem Phys Meteorol | 52B (348-376)

Organic atmospheric aerosols: Review and state of the science

Jacobson, MC; Hansson, HC; Noone, KJ; Charlson, RJ
2000 | Rev Geophys | 38 (2) (267-294)
carbonaceous aerosols , cloud condensation nuclei , dicarboxylic-acids , diffusion denuder sampler , los-angeles basin , mass spectrometry , particle concentrations , polycyclic aromatic hydrocarbons , resolution gas-chromatography , united-states

Atmospheric aerosol particles are known to contain organic carbon material in variable amounts, depending on their location. In some parts of the world, organic compounds make up the majority of the total suspended particle mass. This class of particulate matter is important in a wide range of geophysical and environmental problems, ranging from local issues (e.g., pollution toxicity) to the global scale (e.g., climate change). Unfortunately, the richness of organic chemistry and the highly variable physical properties associated with both natural and anthropogenic organic particles lead to great difficulties in sampling and obtaining complete chemical information on these materials. These obstacles result in an incomplete picture of a potentially significant part of atmospheric chemistry and a correspondingly poor understanding of the geophysical and environmental effects of this aerosol. Given the paucity of quantitative molecular data, the purpose of this paper is not to quantitatively describe the importance of organic aerosols in environmental issues, but rather to present a basis for defining what data are needed. With this goal in mind, we begin with an overview of the major environmental issues known to be affected by organic aerosols, followed by a description of the distribution, sources, and chemical and physical properties of organic aerosols as they are currently understood. Methods used to collect and study organic aerosols are provided, followed by a list of outstanding scientific questions and suggestions for future research priorities.

A physically-based algorithm for estimating the relationship between aerosol mass and cloud droplet number

Glantz, P. and Noone, K. J.
2000 | Tellus B Chem Phys Meteorol | 52B (1216-1231)

Small ice crystals in cirrus clouds: A model study and comparison with in situ observations

Lin, H; Noone, KJ; Ström, J; Heymsfield, AJ
1998 | J. Atmos. Sci. | 55 (11) (1928-1939)

Dynamical influences on cirrus cloud formation process

Lin, H; Noone, KJ; Ström, J; Heymsfield, AJ
1998 | J. Atmos. Sci. | 55 (11) (1940-1949)

Microphysics of clouds: Model vs measurements

Hallberg, A; Wobrock, W; Flossmann, AI; Bower, KN; Noone, KJ; Wiedensohler, A; Hansson, HC; Wendisch, M; Berner, A; Kruisz, C; Laj, P; Facchini, MC; Fuzzi, S; Arends, BG
1997 | Atmos. Environ. | 31 (16) (2453-2462)
aerosol-particles , ccn , cloud chemistry , cloud physics , fog , simulations , water

In order to study the relation between the initial aerosol particle spectrum at cloud base and the resulting droplet spectrum in cloud for the ''Ground-based Cloud Experiment'' field campaign at the Great Dun Fell in 1993 numerical model simulations have been performed. The droplet spectra were calculated from a microphysical model coupled to a dynamic air flow model. The resulting droplet spectra were compared with cloud droplet spectra measured with a forward scattering spectrometer probe. The size distribution and chemical composition of the initial aerosol population were derived from a combination of size distribution and size-segregated chemical measurements below cloud base. From this we concluded that the aerosol particles consisted almost entirely of an inorganic salt. As part of the sensitivity studies two different microphysical models were used, as well as the dynamic flow fields from two different air flow models. As in previous studies we found that the measured droplet spectra were broader and contained larger drops than the modelled spectra. From the sensitivity studies we identified fluctuations in the dynamics as the most likely explanation for these differences. (C) 1997 Elsevier Science Ltd.

Phase partitioning of aerosol constituents in cloud based on single-particle and bulk analysis

Gieray, R; Wieser, P; Engelhardt, T; Swietlicki, E; Hansson, HC; Mentes, B; Orsini, D; Martinsson, B; Svenningsson, B; Noone, KJ; Heintzenberg, J
1997 | Atmos. Environ. | 31 (16) (2491-2502)
atmospheric aerosol , cloud droplet residues , condensation nuclei , droplets , fog , interstitial aerosol , laser microprobe mass spectrometry , methanesulfonic-acid , north-sea , nucleation scavenging

Single-particle analysis, performed by laser microprobe mass spectrometry and bulk analytical techniques were used to study aerosol-cloud interactions within the third field campaign of the EUROTRAC subproject ''ground-based cloud experiments'' at the Great Dun Fell, Cumbria, U.K. in spring 1993. The shape of the ridge made it possible for ground-based instrumentation to sample similar parcels of air before, during and after their transit through the cloud. A single jet five-stage minicascade impactor was used for sampling particles of the interstitial aerosol. A second impactor worked in tandem with a counterflow virtual impactor and collected residues of cloud droplets. Considering marine conditions largest droplets nucleated on sea-salt particles, whereas smaller droplets were formed on sulphate and methane sulphonate containing particles. This clearly indicates chemical inhomogeneities in the droplet phase. Particles, which were disfavoured by droplet formation, often contained the highest amounts of water-insoluble carbonaceous matter. For the submicron size range we found that the carbonaceous matter was always internally mixed with sulphate. The fraction of carbonaceous matter increased with decreasing size. A detectable fraction of particles remained in the cloud interstitial air, although they were in size as well as in composition suitable to form cloud droplets. The findings confirm that nucleation is the most important process affecting phase partitioning in cloud, but that spatial and temporal variations of water vapour supersaturation have also an influence on the observed phase partitioning. Proton induced X-ray emission analysis and light absorption measurements of filter samples showed that the average scavenged fraction was 0.77 for sulphur and 0.57 for soot in clouds formed by continental influenced air and 0.62 and 0.44, respectively, for marine influenced clouds. (C) 1997 Elsevier Science Ltd.

Phase partitioning of aerosol constituents in cloud based on single-particle and bulk analysis.

Gieray, R.; Wieser, P.; Engelhardt, T.; Swietlicki, E.; Hansson, H.-C.; Mentes, B.; Orsini, D.; Martinsson, B.; Svenningsson, B.; Noone, K.J.; Heintzenberg, J.
1997 | Atmos. Environ. | 31 (2491-2502)

The Great Dun Fell Cloud Experiment 1993: an overview

Choularton, T.W.; Colvile, R.N.; Bower, K.N.; Gallagher, M.W.; Wells, M.; Beswick, K.M.; Arends, B.G.; Möls, J.J.; Kos, G.P.A.; Fuzzi, S.; Lind, J.A.; Orsi, G.; Facchini, M.C.; Laj, P.; Gieray, R.; Wieser, P.; Engelhardt, T.; Berner, A.; Kruisz, C.; Möller, D.; Acker, K.; Wieprecht, W.; Lüttke, J.; Levsen, K.; Bizjak, M.; Hansson, H.-C.; Cederfelt, S-I.; Frank, G.; Mentes, B.; Martinsson, B.G.; Orsini, D.; Svenningsson, B.; Swietlicki, E.; Wiedensohler, A.; Noone, K.J.; Pahl, S.; Winkler, P.; Seyffer, E.; Helas, G.; Jaeschke, W.; Georgii, H.W.; Wobrock, W.; Preiss, M.; Maser, R.; Schell, D.; Dollard, G.; Jones, B.; Davies, T.; Sedlak, D.L.; David, M.M.; Wendisch, M.; Cape, J.N.; Hargreaves, K.J.; Sutton, M.A. Storeton-West; R.L., Fowler; D., Hallberg; A., Harrison; R.M.; Peak, J.D.
1997 | Atmos. Environ. | 31 (2393-2405)

The effect of hygroscopicity on cloud droplet formation

Kulmala, M; Korhonen, P; Vesala, T; Hansson, HC; Noone, K; Svenningsson, B
1996 | Tellus B Chem Phys Meteorol | 48 (3) (347-360)
aerosols , albedo , condensation , growth , nitric acid , parameterization , radiation , scattering , temperature , water

The effects of particle hygroscopicity and the availability of condensable material (other than water) in the gas phase on cloud droplet formation and the radiative properties of clouds have been studied using an adiabatic air parcel model with detailed multicomponent condensation. The pre-existing log-normal particle distribution used is bimodal in size and bimodal in hygroscopicity. To simulate this, four log-normal distributions were used and in each mode particles were assumed to be internally mixed, i.e., they are composed partly of salt and partly of an insoluble substance. The mean diameters, standard deviations, total number of pre-existing particles, the mass fraction of the soluble salt and initial concentration of condensable vapour were varied in the simulations. There is a clear effect of hygroscopicity on the activated fraction of aerosol particles in our simulations. Thus hygroscopicity of pre-existing aerosol particles and concentrations of condensable gases can also influence the optical thickness and reflectance of clouds. The change in optical thickness varies as a function of the number concentration of pre-existing particles, having a maximum (Delta tau/tau = 0.2) near a concentration of 1000/cc.

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