High-altitude balloon measurements of atmospheric particulates
Joseph B. Habeck, James Flaten, Graham V. Candler
Abstract
Laminar-turbulent transition of hypersonic boundary layers is believed to be sensitive to particulates that exist in the atmosphere. In order to better understand their role in the transition process, it is necessary to know their number concentration and size distribution at relevant altitudes. This paper reports on preliminary in-situ measurements of particulate number concentrations and size distributions that were performed during two high-altitude balloon flights over southern Minnesota. Vertical profiles of the particulate number concentration for 19 size classes within the 0.2 to 50 $\mu$m diameter size range are presented up to an altitude of 34 km. Particulate size distributions are presented above 22 km and up to an altitude of 34 km.