Cloud Condensation Nuclei number concentrations over the Southern Ocean during the austral summer of 2016/2017.

Dataset abstract

Cloud Condensation Nuclei (CCN) are a subclass of atmospheric aerosol particles, which can be activated to cloud droplets at a certain supersaturation, with respect to water. Due to their abundance, these particles can affect micro-physical properties of clouds, while acting as CCN. It was found that CCN are relevant for the Earth’s radiation budget, by affecting cloud albedo and lifetime. When giving a number concentration of CCN, also the supersaturation (SS) at which it was measured has to be given. Our dataset gives CCN number concentrations measured by a CCN counter (type CCN-100 by DMT, Boulder, US) operated at five different levels of supersaturation (SS=0.15%, 0.2%, 0.3%, 0.5%, 1%) during the Antarctic Circumnavigation Expedition (ACE) cruise over the Southern Ocean, as part of the ACE-SPACE project. Temporal coverage is from December 20, 2016 to March 19, 2017. We give 1-minute averaged and quality controlled CCN number concentrations.

Dataset contents

• ACESPACE_cloud_condensation_nuclei_number_concentration_SS015.csv, data file, comma-separated values
• ACESPACE_cloud_condensation_nuclei_number_concentration_SS020.csv, data file, comma-separated values
• ACESPACE_cloud_condensation_nuclei_number_concentration_SS030.csv, data file, comma-separated values
• ACESPACE_cloud_condensation_nuclei_number_concentration_SS050.csv, data file, comma-separated values
• ACESPACE_cloud_condensation_nuclei_number_concentration_SS100.csv, data file, comma-separated values
• data_file_header.txt, metadata, text
• README.md, metadata, text

The files listed above contain Cloud Condensation Nuclei (CCN) number concentration (N_CCN) values for the Antarctic Circumnavigation Expedition from in-situ measurements. Each file contains only N_CCN values for one of the five measured levels of supersaturation (SS): SS=0.15% in ACESPACE_cloud_condensation_nuclei_number_concentration_SS015.csv, SS=0.2% in ACESPACE_cloud_condensation_nuclei_number_concentration_SS020.csv etc. Values are from 1 Hz measurements and averaged to represent 1-minute intervals.

For latitude and longitude NaN values are given, in cases where positioning data was not available for the given time period. There are no NaN values for CCN number concentration included, in a way that only quality assured data is given.

For every given value of CCN number concentration, the respective supersaturation level is given, although files only contain values for one level only. Additionally, longitude and latitude for the ship’s position at the start time of the averaging period are given.