Atmospheric boundary layer dynamics and aerosol properties based on observations of unmanned research aircraft

• Main Author: Harm-Altstädter, Barbara
• Other Authors: Hecker, Peter, Kottmeier, Christoph
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Niedersächsisches Forschungszentrum für Luftfahrt 2022
• Subjects: doctoral thesis; ddc:62; Veröffentlichung der TU Braunschweig; unbemanntes Forschungsflugzeug > Atmosphärische Grenzschicht > Aerosol > Turbulenz > Polargebiete > unmanned aerial system > atmospheric boundary layer > aerosol > turbulence > polar area; Antarc*; Antarctic; polar night; Sea ice; Weddell Sea
• Online Access: https://doi.org/10.24355/dbbs.084-202205241053-0; https://nbn-resolving.org/urn:nbn:de:gbv:084-2022052411478; https://leopard.tu-braunschweig.de/receive/dbbs_mods_00070714; https://leopard.tu-braunschweig.de/servlets/MCRFileNodeServlet/dbbs_derivate_00049386/Diss_Harm-Altstädter.pdf

The outline of the thesis considers a characterization of dynamic processes and aerosol particles that were studied with unmanned aerial systems (UAS) in the atmospheric boundary layer (ABL) at two investigation areas; in the polar region and at a continental site in Middle Europe. The use of UAS provides a detailed 4-D picture of ABL properties, thus offers a high potential for filling the sparse small-scale observations that exist in the ABLdue to missing measurement tools. The Carolo T200 ”M2AV” (Mini Meteorological Aerial Vehicle) was applied for ABL profiling and investigations of turbulence parameters as part of a Polarstern cruise in the Antarctic Weddell-Sea during polar night between 8 June and 12 August 2013. Eleven research flights were carried out with the M2AV but the field activity was strongly affected by a multitude of critical challenges like icing, strong wind speed and externally driven limitations, mainly influenced by the need of a suitable airfield on sea ice. The results address a detailed investigation of the ABL’s stability, measured above closed sea ice and above open water sections at two different sites on 11 July and 1–2 August 2013. The observations are strongly questioning the common picture of a stably stratified ABL, as generally assumed in models that are applied for polar areas. Since October 2013, the UAS Carolo P360 ”ALADINA” (Application of Light-weight Aircraft for Detecting IN-situ Aerosol) was operated for more than 100 research flights at the Leibniz Institute for Tropospheric Research (TROPOS) site in Melpitz, Germany. The main focus of the study is on investigating the correlation between ABL’s properties and the new particle formation (NPF). This was primarily realized by targeting vertical profiles of ultrafine aerosol particles (UFP, usual size <50 nm) in the lowermost 1 km. According to different selected case studies, a high variability of the observed UFP was identified in the vertical scale and the major impact on the distribution was linked to dynamics of ...