TY  - THES
AU  - Weber, Patrick
TI  - On a multi-spectral method for measuring aerosol properties, suitable for operation on iagos passenger aircraft
VL  - 625
PB  - Univ. Wuppertal
VL  - Dissertation
CY  - Jülich
M1  - FZJ-2024-03409
SN  - 978-3-95806-746-2
T2  - Schriften des Forschungszentrums Jülich Reihe Energie & Umwelt / Energy & Environment
SP  - 123
PY  - 2024
N1  - Dissertation, Univ. Wuppertal, 2023
AB  - The very need for a ground truth for satellite validations and continuous monitoring of essential climate variables are the motivation of this thesis. An extensive set of property information is needed to improve climate modelling and air quality observation. To address this need, we present a new instrument package for the European research infrastructure IAGOS (In-service Aircraft for a Global Observing System). This new instrument will deliver long-term observations of aerosol optical properties and NO2 as proxies for air pollution, conducted globally on board of instrumented passenger aircraft of the IAGOS fleet. The new instrument package is designed and optimised for the environmental conditions on board of commercial aircraft cruising in the upper-troposphere-lower-stratosphere (UTLS) region. The operation onboard commercial aircraft requires that the instruments must operate unattended reliably for at least three months and must comply to strict safety requirements. The new instrument package is equipped with the following devices: Four different CAPS (Cavity Attenuated Phase Shift) tubes measure aerosol light extinction at 630 nm and 450 nm wavelength, as well as nitrogen dioxide. One of the CAPS PMex tubes is used for permanent baseline monitoring for NO2 and PM measurements. A modified POPS (Portable Optical Particle Spectrometer) measures aerosol particle number concentration and size distribution for particle diameters ranging from 125 nm to 4 μm. A water-based condensation particle counter (CPC) measures total aerosol particle number concentration. Continuous developments, improvements and discoveries are the foundation of research. In this thesis, an aerosol optical line was set up to produce aerosol of well-characterised properties as a reference system for aerosol instruments that rely on the aerosol interaction with visible light. By using this line during an extensive instrument evaluation study, the uncertainties for a combined set of instruments measuring aerosol extensive properties and the resulting measurement accuracy for aerosol intensive properties were qualified for a large assembly of aerosol mixtures. Improving a commercially available water-based condensation particle counter for operation under extreme conditions was a second major achievement of this thesis. The improvement consists of enlarging the operation range of this water-based CPC to pressure levels down to 200 hPa as a requirement for using this particle counter in aircraft-based measurements. This modification was later implemented by the manufacturer in a new instrument product. Another significant improvement of the operation of condensation particle counters was achieved by introducing Dimethylsulfoxide (DMSO) as a safe working fluid substitute for alcoholbased condensation particle counters. With this new working fluid, the range for originally condensation particle counters are enlarged since it is now safe to use in working environment with strict safety restrictions and even more use cases can be achieved when this substance is mixed with water.The thesis concludes with the full characterisation of the IAGOS Air Quality instrument which is now ready for certification for operation on commercial passenger aircraft in the framework of IAGOS.
LB  - PUB:(DE-HGF)3 ; PUB:(DE-HGF)11
DO  - DOI:10.34734/FZJ-2024-03409
UR  - https://juser.fz-juelich.de/record/1026465
ER  -