Calibration of a Photometric Cloud Condensation Nucleus Counter Designed for Deployment on a Balloon Package

Delene, David J.; Deshler, Terry

doi:10.1175/1520-0426(2000)017<0459:coapcc>2.0.co;2

Cited by 32 publications

(45 citation statements)

References 20 publications

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“…From Figs. 4 and 5 in Delene and Deshler (2000), the peak voltage appears to lag the peak number by approximately 2 s for S ϭ 0.3%. We performed an additional sensitivity run for case 3, shown in Fig.…”

Section: ϫ3mentioning

confidence: 92%

“…CCN spectra were recorded with a University of Wyoming thermal-gradient static-diffusion cloud chamber (CCNC-100A) Delene and Deshler 2000;Snider et al 2003). The CCN instrument optically counted the number concentration of aerosol activated to cloud drop sizes.…”

Section: B Measurement Descriptionmentioning

confidence: 99%

“…In our estimation of ␣, we do not consider the model-measurement differences due to the fact that the model predicts number concentration and the observations are of scattering voltage. We did not perform concurrent video camera measurements of CCN number within the instrument chamber, as performed by Delene and Deshler (2000). Therefore, we rely on the results from Delene and Deshler to estimate the magnitude of this effect.…”

Section: ϫ3mentioning

confidence: 99%

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Cloud Activating Properties of Aerosol Observed during CELTIC

Stroud

Nenes

Jimenez³

et al. 2007

Journal of the Atmospheric Sciences

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Measurements of aerosol size distribution, chemical composition, and cloud condensation nuclei (CCN) concentration were performed during the Chemical Emission, Loss, Transformation, and Interactions with Canopies (CELTIC) field program at Duke Forest in North Carolina. A kinetic model of the cloud activation of ambient aerosol in the chamber of the CCN instrument was used to perform an aerosol-CCN closure study. This study advances prior investigations by employing a novel fitting algorithm that was used to integrate scanning mobility particle sizer (SMPS) measurements of aerosol number size distribution and aerosol mass spectrometer (AMS) measurements of the mass size distribution for sulfate, nitrate, ammonium, and organics into a single, coherent description of the ambient aerosol in the size range critical to aerosol activation (around 100-nm diameter). Three lognormal aerosol size modes, each with a unique internally mixed composition, were used as input into the kinetic model. For the two smaller size modes, which control CCN number concentration, organic aerosol mass fractions for the defined cases were between 58% and 77%. This study is also unique in that the water vapor accommodation coefficient was estimated based on comparing the initial timing for CCN activation in the instrument chamber with the activation predicted by the kinetic model. The kinetic model overestimated measured CCN concentrations, especially under polluted conditions. Prior studies have attributed a positive model bias to an incomplete understanding of the aerosol composition, especially the role of organics in the activation process. This study shows that including measured organic mass fractions with an assumed organic aerosol speciation profile (pinic acid, fulvic acid, and levoglucosan) and an assumed organic aerosol solubility of 0.02 kg kg Ϫ1 still resulted in a significant model positive bias for polluted case study periods. The slope and y intercept for the CCN predicted versus CCN observed regression was found to be 1.9 and Ϫ180 cm Ϫ3 , respectively. The overprediction generally does not exceed uncertainty limits but is indicative that a bias exists in the measurements or application of model. From this study, uncertainties in the particle number and mass size distributions as the cause for the model bias can be ruled out. The authors are also confident that the model is including the effects of growth kinetics on predicted activated number. However, one cannot rule out uncertainties associated with poorly characterized CCN measurement biases, uncertainties in assumed organic solubility, and uncertainties in aerosol mixing state. Sensitivity simulations suggest that assuming either an insoluble organic fraction or external aerosol mixing were both sufficient to reconcile the model bias.

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Section: ϫ3mentioning

confidence: 92%

Section: B Measurement Descriptionmentioning

confidence: 99%

Section: ϫ3mentioning

confidence: 99%

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Cloud Activating Properties of Aerosol Observed during CELTIC

Stroud

Nenes

Jimenez³

et al. 2007

Journal of the Atmospheric Sciences

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“…The instrument itself consists of a chamber that is circular in the horizontal dimension with ports for sample intake and exhaust, a temperaturecontrolled plate on the chamber bottom, and a photodetector. The theory and operation of this instrument is described by Delene and Deshler (2000), Snider et al (2003), and Snider et al (2006). The method for creating a supersaturated environment in the CCNC-100A is similar to that for the DMT continuous flow diffusion chamber in that a sharp temperature gradient across a small space is used to establish and control the SS.…”

Section: Instruments and Calibrationmentioning

confidence: 99%

“…The detection stage lasts for 20 s during which a steady SS is maintained within the chamber (Snider et al, 2006). The entire process takes 30 to 40 s including the time needed to flush the old sample out of the chamber, admit the new sample, and achieve the steady state SS which can be as much as 15 s depending on how long it takes for the temperature gradient within the chamber to stabilize (Delene and Deshler, 2000;Snider et al, 2006).…”

Section: Instruments and Calibrationmentioning

confidence: 99%

Cold and transition season cloud condensation nuclei measurements in western Colorado

Ward

Cotton

2011

Atmos. Chem. Phys.

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Abstract.Recent studies have shown that orographic precipitation and the water resources that depend on it in the Colorado Rocky Mountains are sensitive to the variability of the region's aerosols, whether emitted locally or from distant sources. However, observations of cloud droplet nucleating aerosols in western Colorado, climatologically upwind of the Colorado Rocky Mountains, have been limited to a few studies at a single, northern site. To address this knowledge gap, atmospheric aerosols were sampled at a ground site in southwestern Colorado and in low-level north to south transects of the Colorado Western Slope as part of the Inhibition of Snowfall by Pollution Aerosols (ISPA-III) field campaign. Total particle and cloud condensation nuclei (CCN) number concentrations were measured for a 24-day period in Mesa Verde National Park, in September and October 2009. Regression analysis showed a positive relationship between mid-troposphere atmospheric pressure to the west of the site and the total particle count at the ground site, but no similar statistically significant relationship was found for the observed CCN. These data were supplemented with particle and CCN number concentration, as well as particle size distribution measurements collected aboard the King Air platform during December 2009. A CCN closure attempt was performed and suggested that the sampled aerosol may have had a low hygroscopicity that changed little with the largescale wind direction. Together, the sampled aerosols from these field programs were characteristic of a rural continental environment with CCN number concentrations that varied slowly in time, and little in space along the Western Slope.

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Observations for Chemistry (In Situ): Particles

Deshler

2024

Reference Module in Earth Systems and Environmental Sciences

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Calibration of a Photometric Cloud Condensation Nucleus Counter Designed for Deployment on a Balloon Package

Cited by 32 publications

References 20 publications

Cloud Activating Properties of Aerosol Observed during CELTIC

Cloud Activating Properties of Aerosol Observed during CELTIC

Cold and transition season cloud condensation nuclei measurements in western Colorado

Observations for Chemistry (In Situ): Particles

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