Size distribution of interstitial and total particles between 18 and 660 nm collected during the Arctic Ocean 2018 expedition

Andrea Baccarini, Julia Schmale

The aerosol size distribution was measured with a custom made scanning mobility particle sizer (SMPS), range 18⁠ – ⁠660 nm.

Aerosols are important for a variety of reasons, one of the most prominent is that a sub-set of the aerosol population can act as cloud condensation nuclei (CCN) influencing cloud formation and the Earth radiative budget. The measurements reported here can be used to investigate aerosol sources and processes. Moreover, an interstitial inlet was used to characterize the interstitial aerosol population during fog events.

Measurements were performed on the 4th deck of icebreaker Oden during August and September 2018 along the track of the expedition. The concentration is reported as dN/dlog(Dp) per cubic centimeter with a 3 minutes time resolution.

Citation

Andrea Baccarini, Julia Schmale (2020) Size distribution of interstitial and total particles between 18 and 660 nm collected during the Arctic Ocean 2018 expedition. Dataset version 1. Bolin Centre Database. https://doi.org/10.17043/oden-ao-2018-aerosol-smps-1

References

Baccarini A, Karlsson L, Dommen J, Duplessis P, Vüllers J, Brooks IM, Saiz-Lopez A, Salter M, Tjernström M, Baltensperger U, Zieger P, Schmale J (2020) Frequent new particle formation over the high Arctic pack ice by enhanced iodine emissions. Nature Communications 11:4924. https://doi.org/10.1038/s41467-020-18551-0

Wang SC, Flagan RC (1989) Scanning Electrical Mobility Spectrometer. J. Aerosol Sci. 20:1485⁠ – ⁠1488. https://doi.org/10.1080/02786829008959441

Data description

The instrument time resolution is 3 minutes that corresponds to the scan time from the smallest (18 nm) to the largest (660 nm) particle diameter. The datetime is reported in the UTC timezone as yyyy-mm-dd HH:MM:SS.

Data are reported as dN/dlog(Dp), where dN is the particle number concentration per cubic centimeter per measured size bin, normalized over the logarithm of the bin width. The bin width is defined as the distance between two diameters. They are spaced equally in log-space with 64 bins per decade.

The instrument was sampling behind two different inlets: a whole-air inlets sampling the entire aerosol population and an interstitial inlet sampling only particles smaller than 1 micrometer. Therefore, during a fog event the interstitial inlet would only sample the non-activated fraction of the aerosol population because fog droplets are larger than the inlet cut-off.

The instrument was switching between the two inlets every 15 minutes, each measurement right before and after the inlet switch was removed to avoid potential issues with pressure drops in the inlet line. The “Inlet status” column indicates behind which inlet the instrument was sampling: 1 indicates the total inlet and 2 the interstitial inlet. The last column in the dataset is a flag to separate between clean data and data that are potentially influenced by the ship exhaust: 1 indicates clean data and 2 contaminated data. The numeric column header corresponds to the starting size of each diameter bin.

The SMPS diameter range used for the aerosol size selection was not kept constant during the entire measurement period. However, in order to keep data consistent, the diameter size bins were resampled on a common grid. The presence of missing data for some diameter bins indicates that the SMPS measurements did not cover that specific size range at that time.

A description of the SMPS instrument is provided by Wang et al. (1989).

Comments

The ship track with latitude and longitude information can be found in the Navigation, meteorological and surface seawater data from the Arctic Ocean 2018 expedition data set.

The data creator ORCIDs are the following:

• Andrea Baccarini: https://orcid.org/0000-0003-4614-247X
• Julia Schmale: https://orcid.org/0000-0002-1048-7962

Data were collected during the Arctic Ocean 2018 expedition on board the Swedish icebreaker (I/B) Oden, which was organized by the Swedish Polar Research Secretariat. The observations were part of the project ‘Aerosol-cloud interactions in the High Arctic’ (PI Paul Zieger, Department of Environmental Science, Stockholm University; see MOCCHA project website with updates).