Cloud condensation nuclei (CCN) concentration during the Arctic Ocean 2018 expedition

Patrick Duplessis, Rachel Y.-W. Chang, Michael Wheeler, Richard Leaitch, Birgitta Svenningsson, Linn Karlsson, Paul Zieger

Measurements of cloud condensation nuclei concentrations in the whole-air sampling inlet (WAI) and the cloud residuals inlet (CVI), using two Cloud Condensation Nuclei Counters (CCNC, Droplet Measurement Technologies, CCN-100). The instruments were calibrated before and after the campaign using ammonium sulfate, and the supersaturation was adjusted accordingly.

This dataset is highly valuable to estimate the hygroscopicity of ambient aerosols and droplet residuals. It can also be used to estimate the maximum supersaturation during cloud formation.

Measurements were performed on the 4th deck of icebreaker Oden during August and September 2018 along the track of the expedition. The instruments scanned through five supersaturation settings of nominal values from 0.1% to 1%. Concentrations are reported as droplets per cubic centimetre, at a 12-minute time resolution (one value per supersaturation per hour).

Map

Citation

Patrick Duplessis, Rachel Y.-W. Chang, Michael Wheeler, Richard Leaitch, Birgitta Svenningsson, Linn Karlsson, Paul Zieger (2023) Cloud condensation nuclei (CCN) concentration during the Arctic Ocean 2018 expedition. Dataset version 1. Bolin Centre Database. https://doi.org/10.17043/oden-ao-2018-ccnc-1

References

Rose, D., Gunthe, S. S., Mikhailov, E., Frank, G. P., Dusek, U., Andreae, M. O., & Pöschl, U. (2008). Calibration and measurement uncertainties of a continuous-flow cloud condensation nuclei counter (DMT-CCNC): CCN activation of ammonium sulfate and sodium chloride aerosol particles in theory and experiment. Atmospheric Chemistry and Physics, 8(5), 1153–1179. https://doi.org/10.5194/acp-8-1153-2008

Roberts, G. C., & Nenes, A. (2005). A Continuous-Flow Streamwise Thermal-Gradient CCN Chamber for Atmospheric Measurements. Aerosol Science and Technology, 39(3), 206–221. https://doi.org/10.1080/027868290913988

Karlsson, L., Baccarini, A., Duplessis, P., Baumgardner, D., Brooks, I. M., Chang, R. Y. W., ... & Zieger, P. (2022). Physical and chemical properties of cloud droplet residuals and aerosol particles during the Arctic Ocean 2018 expedition. Journal of Geophysical Research: Atmospheres, 127(11). https://doi.org/10.1029/2021JD036383

Data description

Data from the whole-air inlet (WAI) and residual inlet (CVI) are separated in two respective files:

1. CCNC_WAI.csv
2. CCNC_CVI.csv

The raw data were collected at 1 Hz frequency and then averaged over the period of stable supersaturation. The first 5 minutes of data following the change from maximum to minimum supersaturation was excluded from the average, and the first 2 minutes following the other four saturation changes were excluded.

1. Timestamp [UTC] Datetime is reported in the UTC time zone.
2. Supersaturation [%] Supersaturation, in %.
3. CCN concentration [cm-3] is the CCN concentration, in unit per cm³. The measurement uncertainty is estimated to be approximately 5 % on CCN concentration, and 0.01 % on supersaturation.
4. clean data [1], contaminated data [0] is a flag to separate between clean data and data that are potentially influenced by the ship exhaust: 1 indicates clean data and 0 contaminated data. NaN values indicate unavailable data due to various causes specific to the instrument, including calibration, maintenance, or failure.

Comments

More information on the CVI measurements can be found in Karlsson et al. (2022).