CCN measurements at the Princess Elisabeth Antarctica research station during three austral summers
Authors: Herenz Paul , Wex Heike , Mangold Alexander , Laffineur Quentin , Gorodetskaya Irina V. , Fleming Zoë L. , Panagi Marios , Stratmann Frank 
Published: January 2019

Abstract. For three austral summer seasons (2013–2016, each from December to February)
aerosol particles arriving at the Belgian Antarctic research station Princess
Elisabeth (PE) in Dronning Maud Land in East Antarctica were characterized.
This included number concentrations of total aerosol
particles (NCN) and cloud condensation nuclei (NCCN),
the particle number size distribution (PNSD), the aerosol particle
hygroscopicity, and the influence of the air mass origin on NCN
and NCCN. In general NCN was found to range from
40 to 6700 cm−3, with a median of 333 cm−3, while
NCCN was found to cover a range between less than 10 and
1300 cm−3 for supersaturations (SSs) between 0.1 % and 0.7 %. It is
shown that the aerosol is dominated by the Aitken mode, being characterized by a
significant amount of small, and therefore likely secondarily formed, aerosol
particles, with 94 % and 36 % of the aerosol particles smaller than
90 and ≈35 nm, respectively. Measurements of the basic
meteorological parameters as well as the history of the air masses arriving
at the measurement station indicate that the station is influenced by both
marine air masses originating from the Southern Ocean and coastal areas
around Antarctica (marine events – MEs) and continental air masses
(continental events – CEs). CEs, which were defined as instances when the air
masses spent at least 90 % of the time over the
Antarctic continent during the last 10 days prior to arrival at the measurements station, occurred during 61 % of the time during which
measurements were done. CEs came along with rather constant NCN
and NCCN values, which we denote as Antarctic continental
background concentrations. MEs, however, cause large fluctuations
in NCN and NCCN, with low concentrations likely caused
by scavenging due to precipitation and high concentrations likely originating
from new particle formation (NPF) based on marine precursors. The application
of HYSPLIT back trajectories in form of the potential source contribution
function (PSCF) analysis indicate that the region of the Southern Ocean is a
potential source of Aitken mode particles. On the basis of PNSDs, together
with NCCN measured at an SS of 0.1 %, median values for the
critical diameter for cloud droplet activation and the aerosol particle
hygroscopicity parameter κ were determined to be 110 nm and 1,
respectively. For particles larger than ≈110 nm the Southern Ocean
together with parts of the Antarctic ice shelf regions were found to be
potential source regions. While the former may contribute sea spray particles
directly, the contribution of the latter may be due to the emission of sea salt
aerosol particles, released from snow particles from surface snow layers,
e.g., during periods of high wind speed, leading to drifting or blowing snow.
The region of the Antarctic inland plateau, however, was not found to feature a
significant source region for aerosol particles in general or for cloud condensation nuclei measured at the PE station in
the austral summer.