Growth Rate Measurements for Single Suspended Droplets Using the Optical Resonance Method

Richardson, C. B.; Lin, Horn-Bond; McGraw, Robert; Tang, I.N.

doi:10.1080/02786828608959080

Cited by 36 publications

(4 citation statements)

References 18 publications

(13 reference statements)

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“…This result suggests that in the atmosphere much of the ammonium sulfate aerosol will be in the form of concentrated aqueous solution. Although there have been some measurements of the kinetics of evaporation and condensation from mixed systems including aqueous ammonium sulfate (21,22), and studies of other systems, such as sodium chloride (23), few studies of the aqueous ammonium sulfate system exist (14,24). A definitive laboratory study of evaporation kinetics from concentrated ammonium sulfate solution is needed to determine whether the presence of such inorganic solutes significantly affects the gasliquid exchange dynamics for atmospheric particles.…”

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confidence: 99%

On the evaporation of ammonium sulfate solution

Drisdell

Saykally

Cohen

2009

Proc. Natl. Acad. Sci. U.S.A.

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Aqueous evaporation and condensation kinetics are poorly understood, and uncertainties in their rates affect predictions of cloud behavior and therefore climate. We measured the cooling rate of 3 M ammonium sulfate droplets undergoing free evaporation via Raman thermometry. Analysis of the measurements yields a value of 0.58 ؎ 0.05 for the evaporation coefficient, identical to that previously determined for pure water. These results imply that subsaturated aqueous ammonium sulfate, which is the most abundant inorganic component of atmospheric aerosol, does not affect the vapor-liquid exchange mechanism for cloud droplets, despite reducing the saturation vapor pressure of water significantly.aerosol ͉ clouds ͉ aqueous ͉ inorganic T he vapor-liquid exchange dynamics of water underlie vital processes in biology, engineering, and atmospheric science. The evaporation and condensation rates of water are particularly important in the formation of cloud particles and are among the largest unknowns in assessing the impact of indirect aerosol effects on the radiative balance in the atmosphere (1). Model studies suggest that evaporation rates Ͻ10% of the maximum rate determined by gas kinetic theory for atmospherically relevant aqueous systems would indicate kinetic control over cloud growth processes, with implications for cloud and aerosol models (2, 3). Attempts to quantify the evaporation and condensation rates of water have yielded values spanning three orders of magnitude, although the most recent values converge to a single order of magnitude (4-10). This uncertainty contributes to the wide variability in cloud model predictions for the anthropogenic effect on size and number of cloud condensation nuclei (CCN) and the corresponding radiative impact on the global system (1,3,11,12).Measuring evaporation and condensation rates of liquid water is difficult because of the complex heat and mass transfer processes occurring in such experiments. The temperature of the liquid surface must be accurately determined and, in most cases, both evaporation and condensation must be properly accounted for. In addition, it has been suggested that some of the earlier measurements of these rates, which typically involved static liquid surfaces, yielded artificially low rates because of the contamination of the liquid with surface impurities (6). Such impurities may well be present in atmospheric conditions; indeed, field measurements of aerosol growth rates appear to indicate such a slowing effect (13,14). In our previous work, we addressed the problem of accurately modeling the heat and mass transfer processes through our measurements of the free evaporation of pure H 2 O and pure D 2 O (4, 5, 10). We also studied relative evaporation rates of isotopomers in mixtures (10,15). In those studies of pure solutions, condensation was negligible, allowing the evaporation process to be modeled accurately and then directly related to the cooling rate of the droplets. We found that evaporation for both pure H 2 O and pure D 2 O occurred at Ϸ60%...

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mentioning

confidence: 99%

On the evaporation of ammonium sulfate solution

Drisdell

Saykally

Cohen

2009

Proc. Natl. Acad. Sci. U.S.A.

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“…The values of kh given in Table 3 have been determined for a temperature of 267 K and a pressure of 900 mbar, with • set equal to 0.01 for all species. The latter is conservative in light of recent reports suggesting that values of • for H20 and many water-soluble species are >0.01, and perhaps close to unity [Wagner, 1982' Richardson et al, 1986Gardner et al, 1987;Mozurkewich et al, 1987;Worsnop et al, 1987].…”

Section: Modelmentioning

confidence: 85%

Possible contribution of N₂O₅ scavenging to HNO₃ observed in winter stratiform cloud

Leaitch¹,

Bottenheim²,

Strapp³

1988

J. Geophys. Res.

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During a winter field study in early 1984, the concentrations of NO3−, SO4=, and H+, measured in cloud water samples collected in the bases of deep stratiform clouds and in the aerosol and gas phases below cloud, suggested a substantial enhancement of NO3− in the cloud water samples for 8 of 12 days. For these 8 days, variations in cloud water NO3−/SO4= were associated with an excess H+/SO4= in the cloud water, indicating HNO3. For the conditions of study, which included subfreezing temperatures and weak solar fluxes to the low‐level cloud, the possibility exists that much of the NO3− in the cloud water was from the formation and subsequent scavenging of N2O5 by cloud droplets. A chemical model set in a Lagrangian framework is used to describe the daytime evolution of odd nitrogen species, including dry deposition of HNO3, under conditions approximating the average conditions for the 8 days. Computations with no cloud scavenging of N2O5 predict an average cloud water NO3− mixing ratio well below the geometric mean determined for the measurements. For the conditions most typical of the observations, the production rate of HNO3 via the cloud scavenging of N2O5 was computed to be approximately equal to that for the gas‐phase production of HNO3.

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“…(9) Vogel, V., Dissertation, Fachbereich Physik, Frankfurt am Main, 1987. (10) Hansen, R. S.; Mann, J. A. J. Appl.…”

Section: Introductionunclassified

“…Theoretical1,10,11 as well as experimental evidence is given for a large number of surfactant monolayers including lipids and polymers. 4,6,[10][11][12][13][14][15][16] An approximate dispersion relation for longitudinal wave propagation has been derived by Lucassen1 The surface dilatational elasticity e strongly affects the wave number of longitudinal waves whereas its influence on the dispersion of transverse capillary waves at filmcovered interfaces is relatively small.…”

Section: Introductionmentioning

confidence: 99%

Resonance of transverse capillary and longitudinal waves as a tool for monolayer investigations at the air-water interface

Vogel

Möbius

1989

Langmuir

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Periodical surface density fluctuations, Le., longitudinal waves, and transverse capillary waves are inherently coupled at fi-covered liquid-gas interfaces. A resonance occm for a particular surface dilatational elasticity where both waves have the same propagation velocity. In this paper, periodical surface density fluctuations are excited in polymer monolayers via the generation of transverse capillary waves. Without contacting the monolayer these transverse ripples are excited by an electrocapillary deflection of the interface (100 Hz to 1 IrHz) and detected by specular reflection of a laser beam from the water surface. The surface pressure fluctuations are investigated by superposing two transverse capillary waves perpendicularly to each other under resonance. In addition, the surface pressurejarea isotherm as well as the propagation characteristics of transverse capillary waves are given for a poly(viny1 acetate) monolayer.

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Growth Rate Measurements for Single Suspended Droplets Using the Optical Resonance Method

Cited by 36 publications

References 18 publications

On the evaporation of ammonium sulfate solution

On the evaporation of ammonium sulfate solution

Possible contribution of N₂O₅ scavenging to HNO₃ observed in winter stratiform cloud

Resonance of transverse capillary and longitudinal waves as a tool for monolayer investigations at the air-water interface

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Growth Rate Measurements for Single Suspended Droplets Using the Optical Resonance Method

Cited by 36 publications

References 18 publications

On the evaporation of ammonium sulfate solution

On the evaporation of ammonium sulfate solution

Possible contribution of N2O5 scavenging to HNO3 observed in winter stratiform cloud

Resonance of transverse capillary and longitudinal waves as a tool for monolayer investigations at the air-water interface

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Product

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About

Possible contribution of N₂O₅ scavenging to HNO₃ observed in winter stratiform cloud