CCN Measurements at Urban Site during CoURAGE

Asa-Awuku, Akua; Jacoby, Stephanie

doi:10.5439/3005016

Title: CCN Measurements at Urban Site during CoURAGE

Dataset
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Abstract

Cloud condensation nuclei (CCN) measurements were collected during CoURAGE from March - June 2025 at the BSEC urban atmospheric chemistry supersite (39.32057 N, 76.6246 W). CCN number concentrations (# cm-3) were obtained at a frequency of 1 second using a cloud condensation nuclei counter (CCN-100, Droplet Measurement Technologies). The CCN counter was operated in stepping mode, measuring CCN over a range of supersaturations from 0.2 to 1.0%. The settings of the instrument were set such that the supersaturation increased in increments of 0.2% up to the maximum supersaturation, and then decreased in increments of 0.2% down to the minimum supersaturation in a repeating cycle. The supersaturation of the instrument was calibrated weekly using ammonium sulfate. The weekly calibrated supersaturation values have been applied to the data. Data during transitions between supersaturation values were removed and replaced with a value of -999. Transitions are defined as the first 210 seconds after a new supersaturation value to ensure the instrument has stabilized following a change in supersaturation. Data were also flagged with a value of -999 if there were concerns with the function of the instrument, specifically the presence of alarm codes, fogging of the optical particle counter (1st stage monitor >more »« less

Authors:

;

Publication Date:: Tue Nov 25 04:00:00 UTC 2025

DOE Contract Number:: AC05-00OR22725

Research Org.:: Atmospheric Radiation Measurement User Facility

Sponsoring Org.:: USDOE Office of Science (SC), Biological and Environmental Research (BER)

Collaborations:: PNNL, BNL, ANL, ORNL

Subject:: CCN number density; Cloud Condensation Nuclei Counter; Cloud condensation nuclei number density; Instrument supersaturation; Tropospheric CCN

OSTI Identifier:: 3005016

DOI:: https://doi.org/10.5439/3005016

Citation Formats


                    Asa-Awuku, Akua, and Jacoby, Stephanie. CCN Measurements at Urban Site during CoURAGE.  United States: N. p., 2025. 
        Web.  doi:10.5439/3005016.

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                    Asa-Awuku, Akua, & Jacoby, Stephanie. CCN Measurements at Urban Site during CoURAGE.  United States.  doi:https://doi.org/10.5439/3005016

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                    Asa-Awuku, Akua, and Jacoby, Stephanie. 2025.  
"CCN Measurements at Urban Site during CoURAGE".  United States.  doi:https://doi.org/10.5439/3005016.  https://www.osti.gov/servlets/purl/3005016. Pub date:Tue Nov 25 04:00:00 UTC 2025

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@article{osti_3005016,

  title        = {CCN Measurements at Urban Site during CoURAGE},

  author       = {Asa-Awuku, Akua and Jacoby, Stephanie},

  abstractNote = {Cloud condensation nuclei (CCN) measurements were collected during CoURAGE from March - June 2025 at the BSEC urban atmospheric chemistry supersite (39.32057 N, 76.6246 W). CCN number concentrations (# cm-3) were obtained at a frequency of 1 second using a cloud condensation nuclei counter (CCN-100, Droplet Measurement Technologies). The CCN counter was operated in stepping mode, measuring CCN over a range of supersaturations from 0.2 to 1.0%. The settings of the instrument were set such that the supersaturation increased in increments of 0.2% up to the maximum supersaturation, and then decreased in increments of 0.2% down to the minimum supersaturation in a repeating cycle. The supersaturation of the instrument was calibrated weekly using ammonium sulfate. The weekly calibrated supersaturation values have been applied to the data. Data during transitions between supersaturation values were removed and replaced with a value of -999. Transitions are defined as the first 210 seconds after a new supersaturation value to ensure the instrument has stabilized following a change in supersaturation. Data were also flagged with a value of -999 if there were concerns with the function of the instrument, specifically the presence of alarm codes, fogging of the optical particle counter (1st stage monitor > 0.4 V), or a sheath to sample flow ratio outside the expected range (< 9 or > 11).},

  doi          = {10.5439/3005016},

  journal      = {},

  number       = ,

  volume       = ,

  place        = {United States},

  year         = {Tue Nov 25 04:00:00 UTC 2025},

  month        = {Tue Nov 25 04:00:00 UTC 2025}

}

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DOI: https://doi.org/10.5439/3005016

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