***** Dataset title *****

Particle number size distribution of fluorescent, hyper-fluorescent, and total aerosol particles measured during the Antarctic Circumnavigation Expedition.

***** Dataset abstract *****

This dataset consists of a 5-minute time series of particle number concentration of fluorescent and total aerosol particles that were measured by wideband integrated by aerosol sensor during the Antarctic Circumnavigation Expedition during the austral summer of 2016/2017. For this dataset, aerosol particles within the optical diameter range of 0.5 μm to 14.5 μm were considered. In this dataset, the time periods when samples are likely contaminated by the ship’s exhaust were removed from the time series.

***** Original data collection *****

The 5-minute time series data was obtained by processing the single aerosol measurements conducted by the wideband integrated by aerosol sensor (WIBS-4, University of Hertfordshire, Hatfield, UK). The raw data was initially stored in CSV format on the data collection computer.

***** Data processing *****

The initial step in aerosol analysis is to label the raw single aerosol data according whether they are fluorescent or not. In summary, aerosol particles exceeding certain user-defined moderate fluorescent signal thresholds are labelled as fluorescent particles, and a subset of fluorescent particles which exceed a user-defined high threshold are labelled as hyper-fluorescent aerosol particles. A detailed explanation of single particle categorization of aerosol particles is included in DOI: 10.5281/zenodo.5109382. 
After labelling single particle data, a Python script was employed to gather single particle data in 5-minute time intervals and conduct statistical analysis in the 5-minute groups. The aerosol size distributions were constructed by taking the histogram of the aerosol optical diameter data within the 5-minute groups. In our analysis, we considered nine size bins with logarithmically equidistant values (log10 based). The size bins were constructed by dividing the distance between 0.5 to 14.5 μm. The count data at each size bins of the histogram were normalized by the logarithm of fractions of upper and lower bounds of each size bin. Furthermore the normalized histogram data was divided by the sampling volume within the 5-minute time interval which was equal to 1.15 l (i.e. instrument sample flow rate (0.23 lpm) multiplied by 5 minutes). Note that for (hyper-)fluorescent aerosol number concentration we only counted the (hyper-)fluorescent single particle data, while for total aerosol number concentration we counted all the single particles within the 5-minute time interval. It is possible that the sampling was contaminated by the ship’s exhaust. Data were removed from time periods during which this was suspected (explained in more detail in Moallemi et al. (2021)).
As we expect that presence of bioaerosols and fluorescent aerosols have time scales in the range of hours, the sampling frequency of WIBS (~ 125 Hz) is reasonably high to capture such variations. In our analysis, we removed samples acquired prior to 2017-01-06 because we suspected that the instrument was not functioning properly before 2017-01-06.

***** Dataset contents *****

-PSD_fluorescent.csv , data file, comma-separated values
-PSD_hyper_fluorescent.csv , data file, comma-separated values
-PSD_hyper_tot.csv , data file, comma-separated values
-data_file_header.txt, metadata, text
-README.txt, metadata, text

***** Dataset contact *****

Alireza Moallemi, Paul Scherrer Institute. ORCID: 0000-0002-9491-1993. Email: alireza.moallemi@psi.ch

***** Dataset license*****

This particle number size distribution of fluorescent, hyper-fluorescent, and total aerosol particles dataset from ACE is made available under the Creative Commons Attribution 4.0 International License (CC BY 4.0) whose full text can be found at https://creativecommons.org/licenses/by/4.0/

***** Dataset citation *****

Please cite this dataset as: 
Moallemi, A., J. Schmale, M. Schnaiter, M. Gysel-Beer, R. Modini and S. Landwehr. (2021). Particle number size distribution of fluorescent, hyper-fluorescent, and total aerosol particles measured during the Antarctic Circumnavigation Expedition. (1.0) [Data set]. Zenodo. https://doi.org/10.5281/zenodo.5109384