Pan-Arctic hourly mean homogenised (dry diameter range 20 to 500 nm) observations of aerosol number size distributions from five arctic long-term observation sites

• Main Authors: Freud, Eyal, Krejci, Radovan, Tunved, Peter, Leaitch, W Richard, Nguyen, Quynh T, Massling, Andreas, Skov, Henrik, Barrie, Leonard
• Format: Dataset
• Language: English
• Published: PANGAEA 2017
• Subjects: Arctic; Arctic Ocean; Tiksi; Station Nord; Siberia
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.877333; https://doi.org/10.1594/PANGAEA.877333

The Arctic environment has an amplified response to global climatic change. It is sensitive to human activities that mostly take place elsewhere. For this study, a multi-year set of observed aerosol number size distributions in the diameter range of 10 to 500 nm from five sites around the Arctic Ocean (Alert, Villum Research Station - Station Nord, Zeppelin, Tiksi and Barrow) was assembled and analysed. A cluster analysis of the aerosol number size distributions, revealed four distinct distributions. Together with Lagrangian air parcel back-trajectories, they were used to link the observed aerosol number size distributions with a variety of transport regimes. This analysis yields insight into aerosol dynamics, transport and removal processes, on both an intra- and inter-monthly scales. For instance, the relative occurrence of aerosol number size distributions that indicate new particle formation (NPF) event is near zero during the dark months, and increases gradually to ~ 40 % from spring to summer, and then collapses in autumn. Also, the likelihood of Arctic Haze aerosols is minimal in summer and peaks in April at all sites. The residence time of accumulation-mode particles in the Arctic troposphere is typically long enough to allow tracking them back to their source regions. Air flow that passes at low altitude over central Siberia and Western Russia is associated with relatively high concentrations of accumulation-mode particles (Nacc) at all five sites - often above 150/cm**3. There are also indications of air descending into the Arctic boundary layer after transport from lower latitudes. The analysis of the back-trajectories together with the meteorological fields along them indicates that the main driver of the Arctic annual cycle of Nacc, on the larger scale, is when atmospheric transport covers the source regions for these particles in the 10-day period preceding the observations in the Arctic. The scavenging of these particles by precipitation is shown to be important on a regional scale and it is most ...