2019, Hartmann, M., Blunier, T., Brügger, S.O., Schmale, J., Schwikowski, M., Vogel, A., Wex, H., Stratmann, F.

The historical development of ice nucleating particle concentrations (NINP) is still unknown. Here, we present for the first time NINP from the past 500 years at two Arctic sites derived from ice core samples. The samples originate from the EUROCORE ice core (Summit, Central Greenland) and from the Lomo09 ice core (Lomonosovfonna, Svalbard). No long-term trend is obvious in the measured samples, and the overall range of NINP is comparable to present-day observations. We observe that the short-term variations in NINP is larger than the long-term variability, but neither anthropogenic pollution nor volcanic eruptions seem to have influenced NINP in the measured temperature range. Shape and onset temperature of several INP spectra suggest that INP of biogenic origin contributed to the Arctic INP population throughout the past. ©2019. The Authors.

2018, Stachlewska, Iwona S., Samson, Mateusz, Zawadzka, Olga, Harenda, Kamila M., Janicka, Lucja, Poczta, Patryk, Szczepanik, Dominika, Heese, Birgit, Wang, Dongxiang, Borek, Karolina, Tetoni, Eleni, Proestakis, Emmanouil, Siomos, Nikolaos, Nemuc, Anca, Chojnicki, Bogdan H., Markowicz, Krzysztof M., Pietruczuk, Aleksander, Szkop, Artur, Althausen, Dietrich, Stebel, Kerstin, Schuettemeyer, Dirk, Zehner, Claus

During August 2016, a quasi-stationary high-pressure system spreading over Central and North-Eastern Europe, caused weather conditions that allowed for 24/7 observations of aerosol optical properties by using a complex multi-wavelength PollyXT lidar system with Raman, polarization and water vapour capabilities, based at the European Aerosol Research Lidar Network (EARLINET network) urban site in Warsaw, Poland. During 24–30 August 2016, the lidar-derived products (boundary layer height, aerosol optical depth, Ångström exponent, lidar ratio, depolarization ratio) were analysed in terms of air mass transport (HYSPLIT model), aerosol load (CAMS data) and type (NAAPS model) and confronted with active and passive remote sensing at the ground level (PolandAOD, AERONET, WIOS-AQ networks) and aboard satellites (SEVIRI, MODIS, CATS sensors). Optical properties for less than a day-old fresh biomass burning aerosol, advected into Warsaw’s boundary layer from over Ukraine, were compared with the properties of long-range transported 3–5 day-old aged biomass burning aerosol detected in the free troposphere over Warsaw. Analyses of temporal changes of aerosol properties within the boundary layer, revealed an increase of aerosol optical depth and Ångström exponent accompanied by an increase of surface PM10 and PM2.5. Intrusions of advected biomass burning particles into the urban boundary layer seem to affect not only the optical properties observed but also the top height of the boundary layer, by moderating its increase.