Competition between Sea Salt and Sulfate Particles as Cloud Condensation Nuclei

Ghan, Steven J.; Guzman, Gina; Abdul-Razzak, Hayder

doi:10.1175/1520-0469(1998)055<3340:cbssas>2.0.co;2

Cited by 140 publications

(150 citation statements)

References 17 publications

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“…Figure 1 of Ghan et al (1998). Curves shown here are for initial equilibration of aerosol at RH of 97% rather than 100%.…”

Section: Discussionmentioning

confidence: 99%

“…Ghan et al (1998) reported that the addition of a sea-salt distribution into a rising parcel containing an (NH 4 ) 2 SO 4 distribution can increase or decrease the overall cloud droplet number depending on the atmospheric conditions. Similarly, coarse dust particles may enhance the cloud droplet number by providing CCN or decrease the droplet number by reducing the cloud saturation and inhibiting activation of numerous fine particles.…”

Section: Equilibrium (Kohler) Theorymentioning

confidence: 99%

“…Condensational particle growth is calculated similar to Majeed and Wexler (2001); however, the saturation ratio of water is determined in the transport equation according to (1)- (3) to account for slightly soluble substances. Since our focus is on the formation of cloud droplets Ghan et al (1998) and allow water competition due to dust to be compared with previous results for sea salt. However, we initially equilibrate aerosol at an RH of 97% rather than 100% (Ghan et al, 1998) to account for kinetic limitations near the cloud base (Nenes et al, 2001;Phinney et al, 2003).…”

Section: /21/2006mentioning

confidence: 99%

“…Since our focus is on the formation of cloud droplets Ghan et al (1998) and allow water competition due to dust to be compared with previous results for sea salt. However, we initially equilibrate aerosol at an RH of 97% rather than 100% (Ghan et al, 1998) to account for kinetic limitations near the cloud base (Nenes et al, 2001;Phinney et al, 2003). Coarse dust is represented by a lognormal distribution with σ g = 2.0 and D g = 1.5 or 2.2 µm, which is suitable for long-range transported dust (e.g., Patterson and Gillette, 1977;McTainsh et al, 1997;Singer et al, 2004).…”

Section: /21/2006mentioning

confidence: 99%

“…Curves in Figure 1 of Ghan et al (1998) illustrating the influence of trimodal sea-salt distributions externally mixed with (NH 4 ) 2 SO 4 on the total number of activated particles were recalculated here using the initial condition of RH=97% (see Figure 10 here). Equilibration of aerosol at an RH of 97% rather than 100% slightly reduces the influence of sea salt on cloud properties.…”

Section: /21/2006mentioning

confidence: 99%

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Influence of dust composition on cloud droplet formation

Kelly

Chuang

Wexler

2007

Atmospheric Environment

128

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Previous studies suggest that interactions between dust particles and clouds are significant; yet the conditions where dust particles can serve as cloud condensation nuclei (CCN) are uncertain. Since major dust components are insoluble, the CCN activity of dust strongly depends on the presence of minor components. However, many minor components measured in dust particles are overlooked in cloud modeling studies. Some of these compounds are believed to be products of heterogeneous reactions involving carbonates. In this study, we calculate with diameters between about 0.6 and 2 µm under some conditions. Dust particles > 2 µm often activate regardless of their composition. Only under very specialized conditions does the addition of a dust distribution into a rising parcel containing fine (NH 4 ) 2 SO 4 particles significantly reduce the total number of activated particles via water competition. Effects of dust on cloud saturation and droplet number via water competition are generally smaller than those reported previously for sea salt. Large numbers of fine dust CCN can significantly enhance the number of activated particles under certain conditions. Improved representations of dust mineralogy and reactions in global aerosol models could improve predictions of the effects of aerosol on climate.

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“…Figure 1 of Ghan et al (1998). Curves shown here are for initial equilibration of aerosol at RH of 97% rather than 100%.…”

Section: Discussionmentioning

confidence: 99%

Section: Equilibrium (Kohler) Theorymentioning

confidence: 99%

Section: /21/2006mentioning

confidence: 99%

Section: /21/2006mentioning

confidence: 99%

Section: /21/2006mentioning

confidence: 99%

See 3 more Smart Citations

Influence of dust composition on cloud droplet formation

Kelly

Chuang

Wexler

2007

Atmospheric Environment

128

View full text Add to dashboard Cite

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Primary marine aerosol‐cloud interactions off the coast of California

et al. 2015

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Primary marine aerosol (PMA)-cloud interactions off the coast of California were investigated using observations of marine aerosol, cloud condensation nuclei (CCN), and stratocumulus clouds during the Eastern Pacific Emitted Aerosol Cloud Experiment (E-PEACE) and the Stratocumulus Observations of Los-Angeles Emissions Derived Aerosol-Droplets (SOLEDAD) studies. Based on recently reported measurements of PMA size distributions, a constrained lognormal-mode-fitting procedure was devised to isolate PMA number size distributions from total aerosol size distributions and applied to E-PEACE measurements. During the 12 day E-PEACE cruise on the R/V Point Sur, PMA typically contributed less than 15% of total particle concentrations. PMA number concentrations averaged 12 cm À3 during a relatively calmer period (average wind speed 12 m/s 1 ) lasting 8 days, and 71 cm À3 during a period of higher wind speeds (average 16 m/s 1 ) lasting 5 days. On average, PMA contributed less than 10% of total CCN at supersaturations up to 0.9% during the calmer period; however, during the higher wind speed period, PMA comprised 5-63% of CCN (average 16-28%) at supersaturations less than 0.3%. Sea salt was measured directly in the dried residuals of cloud droplets during the SOLEDAD study. The mass fractions of sea salt in the residuals averaged 12 to 24% during three cloud events. Comparing the marine stratocumulus clouds sampled in the two campaigns, measured peak supersaturations were 0.2 ± 0.04% during E-PEACE and 0.05-0.1% during SOLEDAD. The available measurements show that cloud droplet number concentrations increased with >100 nm particles in E-PEACE but decreased in the three SOLEDAD cloud events.

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On the Influence of Air Mass Origin on Low‐Cloud Properties in the Southeast Atlantic

et al. 2017

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This study investigates the impact of air mass origin and dynamics on cloud property changes in the Southeast Atlantic (SEA) during the biomass burning season. The understanding of clouds and their determinants at different scales is important for constraining the Earth's radiative budget and thus prominent in climate system research. In this study, the thermodynamically stable SEA stratocumulus cover is observed not only as the result of local environmental conditions but also as connected to large‐scale meteorology by the often neglected but important role of spatial origins of air masses entering this region. In order to assess to what extent cloud properties are impacted by aerosol concentration, air mass history, and meteorology, a Hybrid Single‐Particle Lagrangian Integrated Trajectory cluster analysis is conducted linking satellite observations of cloud properties (Spinning‐Enhanced Visible and Infrared Imager), information on aerosol species (Monitoring Atmospheric Composition and Climate), and meteorological context (ERA‐Interim reanalysis) to air mass clusters. It is found that a characteristic pattern of air mass origins connected to distinct synoptical conditions leads to marked cloud property changes in the southern part of the study area. Long‐distance air masses are related to midlatitude weather disturbances that affect the cloud microphysics, especially in the southwestern subdomain of the study area. Changes in cloud effective radius are consistent with a boundary layer deepening and changes in lower tropospheric stability (LTS). In the southeastern subdomain cloud cover is controlled by a generally higher LTS, while air mass origin plays a minor role. This study leads to a better understanding of the dynamical drivers behind observed stratocumulus cloud properties in the SEA and frames potentially interesting conditions for aerosol‐cloud interactions.

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Competition between Sea Salt and Sulfate Particles as Cloud Condensation Nuclei

Cited by 140 publications

References 17 publications

Influence of dust composition on cloud droplet formation

Influence of dust composition on cloud droplet formation

Primary marine aerosol‐cloud interactions off the coast of California

On the Influence of Air Mass Origin on Low‐Cloud Properties in the Southeast Atlantic

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