2026-10-01T21:30:02Zhttps://skemman.is/oai/request

oai:skemman.is:1946/452092023-06-16T14:05:19Zcom_1946_35053com_1946_3515col_1946_35055

Landbúnaðarháskóli Íslands Ellie Fisher 2000- Tuukka Petäjä Henrik Skov Andreas Massling Juan Andrés Casquero Vera Atmospheric aerosols are solid or liquid phase particles which are suspended in ambient air. These particles have an impact on the climate through direct and indirect radiative forcing, and their measurement presents challenges in high latitude environments where concentrations may fall under the detection limit of the responsible instruments. In order to both qualify and quantify the contribution of aerosol particles to environmental change at higher latitudes, it is important to understand their microphysical and optical properties, which control their interaction with visible wavelength radiation. This thesis focuses on the characterisation of the aforementioned aerosol properties in a High Arctic environment, Villum Research Station (Northeast Greenland), during two six-month observation periods in 2020 and 2021. The parameters presented in the analysis are particle total number concentration and size distribution in the 0.3 - 10 µm size range, particle scattering coefficients σsp, particle absorption coefficients σap, and Ångström exponents describing the wavelength dependence of both optical coefficients. The seasonal variability and distribution of these properties was analysed, and case studies of exceptional particle number concentration identified as particle transport events to evaluate the contribution of local and long-distance source regions to the overall aerosol population at the station. The results of the analysis show that there is a notable seasonality to both number concentration and optical characteristics of aerosol particles at Villum Research Station, with median values for these parameters at their highest in the winter, followed by the autumn and then the summer. The dominant species during episodes of exceptional particle number concentrations were found to be dust, Elemental Carbon/Organic Carbon (EC/OC) and mixed aerosols, with source regions across continental Greenland, the Canadian Archipelago and Arctic Ocean. 30 ECTS thesis approved in partial fulfillment of a double Nordic Master MSc degree in environmental changes at higher latitudes (EnCHiL), from University of Helsinki and Agricultural University of Iceland. 2023-06-16T13:59:06Z 2023-06-16T13:59:06Z 2023-06-16T13:59:06Z 2023-06-16T13:59:06Z 2023-05 http://hdl.handle.net/1946/45209 en Umhverfisbreytingar á norðurslóðum Environmental changes at Higher Latitudes (EnCHiL) Atmospheric Aerosol Particle North-Eash Greenland Aerosol Number Concentration Arosol Optical Properties Ångström Exponent Back Trajectories Aerosol Particle Sources Characterisation of Microphysical and Optical Properties of Atmospheric Aerosols in a High Arctic environment: Villum Research Station, NE Greenland Thesis Master's