Influence of Stratospheric-Tropospheric Exchange on Aerosol Particle Concentrations in the UT/LMS - a Statistical Analysis of Aircraft Data from the IAGOS-CARIBIC Observatory
Monday, 19 March 2018: 11:30
Salon Vilaflor (Hotel Botanico)
Denise Nadine Assmann1, Markus Hermann1, Andreas Weigelt2, Bengt G Martinsson3, Carl A M Brenninkmeijer4, Armin Rauthe-Schöch5, Peter F. J. van Velthoven6, Harald Boenisch7 and Andreas Zahn7, (1)Leibniz Institute for Tropospheric Research, Leipzig, Germany, (2)BSH Federal Maritime and Hydrographic Agency, Hamburg, Germany, (3)Lund University, Lund, Sweden, (4)Max Planck Institute for Chemistry, Mainz, Germany, (5)Deutscher Wetterdienst (DWD), Offenbach am Main, Germany, (6)Royal Netherlands Meteorological Institute, De Bilt, Netherlands, (7)Karlsruhe Institute of Technology, Karlsruhe, Germany
Abstract:
Submicrometer aerosol particles in the upper troposphere and lowermost stratosphere (UT/LMS) influence the Earth`s radiation budget not only directly, but also indirectly by acting as cloud condensation nuclei and by changing trace gas concentrations through heterogeneous chemical processes. Since 1997, regular in situ measurements of UT/LMS aerosol particles have been conducted by TROPOS, Germany, and Lund University, Sweden, using the CARIBIC passenger aircraft observatory (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container; www.iagos.org/iagos-caribic/). Aerosol particle number concentrations and the submicrometer particle size distribution are measured using three condensation particle counters and one optical particle size spectrometer. Moreover, particle elemental composition is determined using an aerosol impactor sampler and post-flight ion beam analyses (Particle Induced X-ray Emission (PIXE), Particle Elastic Scattering Analysis (PESA)) at Lund University.
Based on this unique data set, including meteorological analyses by KNMI, we present seasonal distributions of UT/LMS particle number concentrations, e.g. as potential temperature - equivalent latitude plots. The results are interpreted with respect to aerosol microphysics and transport using IAGOS-CARIBIC trace gas data like ozone or acetonitrile. The influence of deep convective clouds and other transport processes are clearly visible in these distributions. We investigated four transport pathways into the UT/LMS: deep convective clouds, warm conveyor belts, downward transport with the Brewer-Dobson-circulation, and transport along isentropes, and analyze their influence on the UT/LMS aerosol particle number concentration and size distribution. The data set contains a wealth of information on UT/LMS transport and aerosol sources, sinks, and ageing and thus is a unique treasure to validate remote sensing instruments and global atmospheric models.
