Influence of Functional Groups on Organic Aerosol Cloud Condensation Nucleus Activity

2014 ◽  
Vol 48 (17) ◽  
pp. 10182-10190 ◽  
Author(s):  
Sarah R. Suda ◽  
Markus D. Petters ◽  
Geoffrey K. Yeh ◽  
Christen Strollo ◽  
Aiko Matsunaga ◽  
...  
Keyword(s):  
Functional Groups ◽  
Condensation Nucleus ◽  
Organic Aerosol ◽  
Cloud Condensation Nucleus ◽  
Aerosol Cloud

scholarly journals Widening the gap between measurement and modelling of secondary organic aerosol properties?

2010 ◽  
Vol 10 (6) ◽  
pp. 2577-2593 ◽  
Author(s):  
N. Good ◽  
D. O. Topping ◽  
J. Duplissy ◽  
M. Gysel ◽  
N. K. Meyer ◽  
...  
Keyword(s):  
Surface Tension ◽  
Water Activity ◽  
Condensation Nucleus ◽  
Organic Aerosol ◽  
Solute Concentration ◽  
Complex Model ◽  
Cloud Condensation Nucleus ◽  
Saturated Water ◽  
Cloud Activation ◽  
Ccn Activity

Abstract. The link between measured sub-saturated hygroscopicity and cloud activation potential of secondary organic aerosol particles produced by the chamber photo-oxidation of α-pinene in the presence or absence of ammonium sulphate seed aerosol was investigated using two models of varying complexity. A simple single hygroscopicity parameter model and a more complex model (incorporating surface effects) were used to assess the detail required to predict the cloud condensation nucleus (CCN) activity from the sub-saturated water uptake. Sub-saturated water uptake measured by three hygroscopicity tandem differential mobility analyser (HTDMA) instruments was used to determine the water activity for use in the models. The predicted CCN activity was compared to the measured CCN activation potential using a continuous flow CCN counter. Reconciliation using the more complex model formulation with measured cloud activation could be achieved widely different assumed surface tension behavior of the growing droplet; this was entirely determined by the instrument used as the source of water activity data. This unreliable derivation of the water activity as a function of solute concentration from sub-saturated hygroscopicity data indicates a limitation in the use of such data in predicting cloud condensation nucleus behavior of particles with a significant organic fraction. Similarly, the ability of the simpler single parameter model to predict cloud activation behaviour was dependent on the instrument used to measure sub-saturated hygroscopicity and the relative humidity used to provide the model input. However, agreement was observed for inorganic salt solution particles, which were measured by all instruments in agreement with theory. The difference in HTDMA data from validated and extensively used instruments means that it cannot be stated with certainty the detail required to predict the CCN activity from sub-saturated hygroscopicity. In order to narrow the gap between measurements of hygroscopic growth and CCN activity the processes involved must be understood and the instrumentation extensively quality assured. It is impossible to say from the results presented here due to the differences in HTDMA data whether: i) Surface tension suppression occurs ii) Bulk to surface partitioning is important iii) The water activity coefficient changes significantly as a function of the solute concentration.

scholarly journals Widening the gap between measurement and modelling of secondary organic aerosol properties?

2009 ◽  
Vol 9 (5) ◽  
pp. 22619-22657
Author(s):  
N. Good ◽  
D. O. Topping ◽  
J. Duplissy ◽  
M. Gysel ◽  
N. K. Meyer ◽  
...  
Keyword(s):  
Surface Tension ◽  
Water Activity ◽  
Condensation Nucleus ◽  
Organic Aerosol ◽  
Solute Concentration ◽  
Complex Model ◽  
Cloud Condensation Nucleus ◽  
Saturated Water ◽  
Cloud Activation ◽  
Ccn Activity

Abstract. The link between measured sub-saturated hygroscopicity and cloud activation potential of secondary organic aerosol particles produced by the chamber photo-oxidation of α-pinene in the presence or absence of ammonium sulphate seed aerosol was investigated using two models of varying complexity. A simple single hygroscopicity parameter model and a more complex model (incorporating surface effects) were used to assess the detail required to predict the cloud condensation nucleus (CCN) activity from the sub-saturated water uptake. Sub-saturated water uptake measured by three hygroscopicity tandem differential mobility analyser (HTDMA) instruments was used to determine the water activity for use in the models. The predicted CCN activity was compared to the measured CCN activation potential using a continuous flow CCN counter. Reconciliation using the more complex model formulation with measured cloud activation required widely different assumed surface tension behavior of the growing droplet; this was entirely determined by the instrument used as the source of water activity data. This unreliable derivation of the water activity as a function of solute concentration from sub-saturated hygroscopicity data indicates a limitation in the use of such data in predicting cloud condensation nucleus behavior of particles with a significant organic fraction. Similarly, the ability of the simpler single parameter model to predict cloud activation behaviour was dependent on the instrument used to measure sub-saturated hygroscopicity and the relative humidity used to provide the model input. However, agreement was observed for inorganic salt solution particles, which were measured by all instruments in agreement with theory. The difference in HTDMA data from proven instruments means that it cannot be stated with certainty the detail required to predict the CCN activity from sub-saturated hygroscopicity. In order to narrow the gap between measurements of hygroscopic growth and CCN activity the processes involved must be understood. It is impossible to say from the results presented here whether: i) Surface tension suppression occurs ii) Bulk to surface partitioning is important iii) The water activity coefficient changes significantly as a function of the solute concentration.

scholarly journals Towards closing the gap between hygroscopic growth and activation for secondary organic aerosol: Part 1 – Evidence from measurements

2009 ◽  
Vol 9 (12) ◽  
pp. 3987-3997 ◽  
Author(s):  
H. Wex ◽  
M. D. Petters ◽  
C. M. Carrico ◽  
E. Hallbauer ◽  
A. Massling ◽  
...  
Keyword(s):  
Pure Water ◽  
Condensation Nucleus ◽  
Organic Aerosol ◽  
Cloud Condensation Nucleus ◽  
Hygroscopic Growth ◽  
The Past ◽  
Particle Activation ◽  
Closing The Gap ◽  
Scattering Signal ◽  
Made In

Abstract. Secondary Organic Aerosols (SOA) studied in previous laboratory experiments generally showed only slight hygroscopic growth, but a much better activity as a CCN (Cloud Condensation Nucleus) than indicated by the hygroscopic growth. This discrepancy was examined at LACIS (Leipzig Aerosol Cloud Interaction Simulator), using a portable generator that produced SOA particles from the ozonolysis of α-pinene, and adding butanol or butanol and water vapor during some of the experiments. The light scattering signal of dry SOA-particles was measured by the LACIS optical particle spectrometer and was used to derive a refractive index for SOA of 1.45. LACIS also measured the hygroscopic growth of SOA particles up to 99.6% relative humidity (RH), and a CCN counter was used to measure the particle activation. SOA-particles were CCN active with critical diameters of e.g. 100 nm and 55 nm at super-saturations of 0.4% and 1.1%, respectively. But only slight hygroscopic growth with hygroscopic growth factors ≤1.05 was observed at RH<98% RH. At RH>98%, the hygroscopic growth increased stronger than would be expected if a constant hygroscopicity parameter for the particle/droplet solution was assumed. An increase of the hygroscopicity parameter by a factor of 4–6 was observed in the RH-range from below 90% to 99.6%, and this increase continued for increasingly diluted particle solutions for activating particles. This explains an observation already made in the past: that the relation between critical super-saturation and dry diameter for activation is steeper than what would be expected for a constant value of the hygroscopicity. Combining measurements of hygroscopic growth and activation, it was found that the surface tension that has to be assumed to interpret the measurements consistently is greater than 55 mN/m, possibly close to that of pure water, depending on the different SOA-types produced, and therefore only in part accounts for the discrepancy between hygroscopic growth and CCN activity observed for SOA particles in the past.

scholarly journals Investigating potential biases in observed and modeled metrics of aerosol-cloud-precipitation interactions

2011 ◽  
Vol 11 (9) ◽  
pp. 4027-4037 ◽  
Author(s):  
H. T. Duong ◽  
A. Sorooshian ◽  
G. Feingold
Keyword(s):  
Liquid Water ◽  
Drop Size ◽  
Rain Rate ◽  
Rate Sensitivity ◽  
Condensation Nucleus ◽  
Cloud Condensation Nucleus ◽  
Liquid Water Path ◽  
Full Spectrum ◽  
Aerosol Cloud ◽  
The Impact

Abstract. This study utilizes large eddy simulation, aircraft measurements, and satellite observations to identify factors that bias the absolute magnitude of metrics of aerosol-cloud-precipitation interactions for warm clouds. The metrics considered are precipitation susceptibility So, which examines rain rate sensitivity to changes in drop number, and a cloud-precipitation metric, χ, which relates changes in rain rate to those in drop size. While wide ranges in rain rate exist at fixed cloud drop concentration for different cloud liquid water amounts, χ and So are shown to be relatively insensitive to the growth phase of the cloud for large datasets that include data representing the full spectrum of cloud lifetime. Spatial resolution of measurements is shown to influence the liquid water path-dependent behavior of So and χ. Other factors of importance are the choice of the minimum rain rate threshold, and how to quantify rain rate, drop size, and the cloud condensation nucleus proxy. Finally, low biases in retrieved aerosol amounts owing to wet scavenging and high biases associated with above-cloud aerosol layers should be accounted for. The paper explores the impact of these effects for model, satellite, and aircraft data.

scholarly journals Investigating potential biases in observed and modeled metrics of aerosol-cloud-precipitation interactions

2010 ◽  
Vol 10 (12) ◽  
pp. 29897-29922
Author(s):  
H. T. Duong ◽  
A. Sorooshian ◽  
G. Feingold
Keyword(s):  
Liquid Water ◽  
Drop Size ◽  
Rain Rate ◽  
Rate Sensitivity ◽  
Condensation Nucleus ◽  
Cloud Condensation Nucleus ◽  
Liquid Water Path ◽  
Full Spectrum ◽  
Aerosol Cloud ◽  
The Impact

Abstract. This study utilizes large eddy simulation, aircraft measurements, and satellite observations to identify factors that bias the absolute magnitude of metrics of aerosol-cloud-precipitation interactions for warm clouds. The metrics considered are precipitation susceptibility So, which examines rain rate sensitivity to changes in drop number, and a cloud-precipitation metric, χ, which relates changes in rain rate to those in drop size. While wide ranges in rain rate exist at fixed cloud drop concentration for different cloud liquid water amounts, χ and So are shown to be relatively insensitive to the growth phase of the cloud for large datasets that include data representing the full spectrum of cloud lifetime. Spatial resolution of measurements is shown to influence both the magnitude and liquid water path-dependent behavior of So and χ. Other factors of importance are the choice of how to quantify rain rate, drop size, and the cloud condensation nucleus proxy. Finally, low biases in retrieved aerosol amounts owing to wet scavenging and high biases associated with above-cloud aerosol layers should be accounted for. The paper explores the impact of these effects for model, satellite, and aircraft data.

scholarly journals Cloud condensation nucleus activity of secondary organic aerosol particles mixed with sulfate

2007 ◽  
Vol 34 (24) ◽  
Author(s):  
Stephanie M. King ◽  
Thomas Rosenoern ◽  
John E. Shilling ◽  
Qi Chen ◽  
Scot T. Martin
Keyword(s):  
Secondary Organic Aerosol ◽  
Aerosol Particles ◽  
Condensation Nucleus ◽  
Organic Aerosol ◽  
Cloud Condensation Nucleus

The effect of atmospheric nitric acid vapor on cloud condensation nucleus activation

1993 ◽  
Vol 98 (D12) ◽  
pp. 22949 ◽  
Author(s):  
M. Kulmala ◽  
A. Laaksonen ◽  
P. Korhonen ◽  
T. Vesala ◽  
T. Ahonen ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Condensation Nucleus ◽  
Cloud Condensation Nucleus ◽  
Acid Vapor
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