Aircraft-based observation of meteoric material in lower stratospheric aerosol particles between 15 and 68°N

Abstract

Abstract. In this paper we analyze aerosol particle composition measurements from five research missions conducted between 2014 and 2018 sampling the upper troposphere and lower stratosphere (UTLS), to assess the meridional extent of particles containing meteoric material. Additional data sets from a ground based study and from a low altitude aircraft mission are used to confirm the existence of meteoric material in lower tropospheric particles. Single particle laser ablation techniques with bipolar ion detection were used to measure the chemical composition of particles in a size range of approximately 150\u2009nm to 3\u2009μm. The five UTLS aircraft missions cover a latitude range from 15 to 68°\u2009N, altitudes up to 21\u2009km, and a potential temperature range from 280 to 480\u2009K. In total, 338\u2009363 single particles were analyzed, of which 147\u2009338 particles were measured in the stratosphere. Of these particles, 50\u2009688 were characterized by high abundances of magnesium, iron, and rare iron oxide compounds, together with sulfuric acid. This particle type was found almost exclusively in the stratosphere (48\u2009610 particles) and is interpreted as meteoric material immersed or dissolved within stratospheric sulfuric acid particles. Below the tropopause, the observed fraction of this particle type decreases sharply. However, small fractional abundances were observed below 3000\u2009m\u2009a.s.l. in the Canadian Arctic and also at the Jungfraujoch high altitude station (3600\u2009m\u2009a.s.l.). Thus, the removal pathway by sedimentation and/or mixing into the troposphere is confirmed. In the tropical lower stratosphere, only a small fraction (