Abstract:
The Uncrewed Aircraft System (UAS) Multipurpose Airborne Sensor Carrier, version 3 (MASC-3), which is capable
of measuring the three-dimensional wind vector, air temperature, and humidity at high resolution, was used in this
thesis as a starting point in the development of a system that can simultaneously measure meteorological variables,
atmospheric electricity, and aerosol particle concentration and size distribution. The aim of this development
was to be able to accurately record Saharan dust events and, in contrast to existing measurements, to make insitu measurements of all of the above variables simultaneously. This is important because no such combined
measurements exist to date, and in particular, the influence of atmospheric electricity on aerosol particle transport is
still largely unexplored. This thesis consists of three publications, each dealing with one aspect of this combined
measurement system. First, MASC-3 was used to measure the local wind field in an Arctic fjord at high resolution.
It was shown that the wind field in Kongsfjorden, in the immediate vicinity of the Ny-Alesund research station on ˚
Svalbard, is complex and strongly influenced by the local terrain. MASC-3 captured small-scale katabatic flows
that affect aerosol particle transport in the immediate vicinity of the research station, which are not resolved in
large-scale numerical models. Second, a sensor payload was developed for MASC-3 to measure the space charge in
the atmospheric electric field. Validation measurements of this sensor system were performed by flying MASC-3
past a 100 m high metallic measurement mast. A simulation of the electric field around the mast was compared with
the measurement data, and it was shown that MASC-3 was able to measure the changes in the electric field around
the mast with low noise after the signal from the charge sensors was corrected to remove the influence of the aircraft
motion. Finally, a low-cost Optical Particle Counter (OPC) was integrated into MASC-3 to measure aerosol particle
concentration and size distribution. For this purpose, the OPC was equipped with a passive aspiration system and a
diffusion dryer and integrated into an airfoil-shaped pod. The measurement system was validated both in ambient
conditions against a reference instrument and in a wind tunnel. The three measurement methods were combined
in the measurement of a Saharan dust event over Cyprus, where aerosol particle concentration, wind, temperature,
humidity, and space charge were measured simultaneously. The resulting measurements can be used in the future to
investigate fundamental relationships in aerosol particle transport.
