2 research outputs found
Jungfraujoch, Switzerland, cloud condensation nuclei concentration, 2012-2014
cloud condensation nuclei concentration, Jungfraujoch, Switzerland, 2012-201
Using Novel Molecular-Level Chemical Composition Observations of High Arctic Organic Aerosol for Predictions of Cloud Condensation Nuclei
Predictions of cloud droplet activation in the late summertime
(September) central Arctic Ocean are made using κ-Köhler theory with novel observations of the aerosol chemical
composition from a high-resolution time-of-flight chemical ionization
mass spectrometer with a filter inlet for gases and aerosols (FIGAERO-CIMS)
and an aerosol mass spectrometer (AMS), deployed during the Arctic Ocean 2018 expedition onboard the Swedish icebreaker Oden. We find that the hygroscopicity parameter κ of the total aerosol is 0.39 ± 0.19 (mean ±
std). The predicted activation diameter of ∼25 to 130 nm particles
is overestimated by 5%, leading to an underestimation of the cloud
condensation nuclei (CCN) number concentration by 4–8%. From
this, we conclude that the aerosol in the High Arctic late summer
is acidic and therefore highly cloud active, with a substantial CCN
contribution from Aitken mode particles. Variability in the predicted
activation diameter is addressed mainly as a result of uncertainties
in the aerosol size distribution measurements. The organic κ
was on average 0.13, close to the commonly assumed κ of 0.1, and therefore did not significantly influence the predictions.
These conclusions are supported by laboratory experiments of the activation
potential of seven organic compounds selected as representative of
the measured aerosol