Development of a calibration system for measuring aerosol particles in the stratosphere
Joseph B. Habeck, Christopher J. Hogan, James Flaten, Graham V. Candler
Abstract
View Video Presentation: https://doi.org/10.2514/6.2022-1582.vid Characterization of the aerosol environment in the stratosphere is needed to better understand the role of aerosol particles in high-speed boundary layer transition. This paper presents the development and initial testing of a calibration system for optical particle counters that measure aerosol particles in the stratosphere via high-altitude balloon platforms. The calibration system is currently capable of replicating a range of low-pressures corresponding to altitudes between 24 and 37 km, a range of aerosol velocities between 1 and 5 m/s, and generating aerosol particle sizes ranging from 0.5 to 5.0 micrometers. The initial testing consisted of applying the calibration system to evaluate the performance of a modified Alphasense OPC-N3 in the 20 to 3 Torr range (corresponding to altitudes of 24 to 37 km). It was found that detection efficiency appears to be highly dependent on the ambient pressure and there exists a critical pressure below which the OPC-N3 fails to measure the particle size distribution. The results also suggest that the low-pressure environment limits the detection efficiency for larger particles.