Regular Mass Spectrometric Aerosol Particle Measurements in the Upper Troposphere and Lowermost Stratosphere (AMS-CARIBIC 2)
Final Report Abstract
Particles in the upper troposphere and lowermost stratosphere significantly influences the radiative balance of the Earth due to their long lifetime in this atmospheric region, the surface area they provide for heterogeneous chemistry, and their role in the formation of ice clouds. The particle size distribution and the chemical composition are the most important aerosol parameters in this respect. However, due to technical and financial issues, our knowledge of these parameters is far from complete. As consequence, in 1994 the CARIBIC project was initiated. In this project, regular measurements of trace gases and aerosol particles in 8-12 km altitude have been conducted with an instrument container flown aboard a commercial aircraft platform. In a predecessor DFG project, an airworthy Aerosol Mass Spectrometer (AMS) was constructed for CARIBIC. This CARIBIC-AMS can measure quantitative particle mass concentrations of non-refractory aerosol species, such as organics, nitrate, sulphate, ammonium, and chloride, in the size range 50 - 800 nm particle diameter. In order to assess the CARIBIC-AMS measurement capability, in this project several ground tests were carried out. The agreement between the CARIBIC-AMS and the reference instruments was much better than the typical stated 30% uncertainty for AMS instruments. In order to provide quantitative particle mass concentrations the material dependent ionization efficiency (ions per molecule of a compound) of the CARIBIC-AMS was determined. Also the sizing capability of the CARIBIC-AMS was tested and shows a better performance than the classical AMS arrangement. Besides ground calibrations, in-flight calibrations were programmed and implemented in the automatically running CARIBIC-AMS. For the instrument checks between the flight sequences, check routines were developed and implemented. In May 2018 the CARIBIC-AMS was flown for the first time. A row of 46 measurements flights were conducted, until in March 2020 Lufthansa decided to ground the CARIBIC aircraft, because of the COVID-19 lockdown. The aircraft was not brought back into service and thus CARIBIC-AMS measurements ended for the time being. Not all flights yielded useable data, as the fully automated CARIBIC-AMS had the usual teething problems of new instruments. The available data were quality checked and analyzed with respect to case studies such as the Raikoke volcanic eruption in 2019. The time without a carrier platform was also used to fly the CARIBIC-AMS in a research campaign. Data analysis and respective publications are in progress. After having successfully accomplished an aircraft changeover to a new Lufthansa Airbus A350, the CARIBIC-AMS measurements will be hopefully resumed end of 2025.
Publications
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First results of aerosol mass spectrometer measurements on board of a passenger aircraft within the IAGOS-CARIBIC project, Presentation at the European Aerosol Conference (EAC), Aachen, Germany, 30. August - 4. September, 2020
Schulz, C. et al.
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Impact of the Raikoke volcanic eruption 2019 on the Northern Hemisphere UT/LS aerosol load and properties as seen from IAGOS-CARIBIC in-situ observations. Presentation at the European Aerosol Conference (EAC), Aachen, Germany, 30. August - 4. September, 2020
Petzold, A. et al.
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Evolution of the Raikoke volcanic plume in the Northern Hemisphere UT/LS over 9 months past eruption as seen from IAGOS-CARIBIC in-situ observations. Presentation at the EGU General Assembly, Vienna, Austria, 19. - 30. April, 2021
Petzold, A. et al.
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Spatiotemporal Distributions of Aerosol Particles at the Northern Hemispheric Extratropical Tropopause based on IAGOS-CARIBIC Observations, Presentation at the TP Challenges Conference, Mainz, Germany, 11.-15. March, 2024
Hermann, M. et al.
