European Facility For Airborne Research Nov. 29, 2020, 01:45
|Name||Aerosol and Cloud Particle Sampling|
|Description||The EWG on Aerosol and Cloud Particle Sampling addresses the following topics:
Atmospheric research aircraft deploy a great variety of sensors to measure atmospheric state parameters (temperature, pressure, and altitude), gas-phase constituents, and particles. For these measurements, especially for aerosol and cloud particles, it is fundamental to have an air sample representative of the free stream atmospheric environment. However, appropriate air sampling from aircraft is a challenge, because air entering a sampling inlet or sensor can be influenced by the aircraft itself or by the sampling device. Movement of air around the aircraft fuselage can affect not only the airflow speed and direction, but also the concentrations of various atmospheric components, especially of aerosol and cloud particles.
Once particles enter a sampling inlet, additional biases can occur. These potential changes are a function of sensor location and shape, particle size and composition, and the type of measurement being made. In some cases, errors due to sampling location and inlet type may be larger than errors inherent in the measurement itself. Errors can be minimised if flow speed, flow direction, and particle behavior is known for sampling locations and inlets, so the best environment can be chosen for a specific measurement. Once a location and inlet is chosen, remaining biases must be understood and quantified for a complete analysis of the measurement uncertainty.