Book/Dissertation / PhD Thesis

FZJ-2021-01991

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Atmospheric Trace Gas Measurements Using Chemical Ionisation Time-of-Flight Mass Spectrometry

Li, Y. (Corresponding author)FZJ*

2020
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich
ISBN: 978-3-95806-520-8

Please use a persistent id in citations: http://hdl.handle.net/2128/27719  urn:nbn:de:0001-2020121107

Abstract: Atmospheric trace gases whose concentrations range from parts per million by volume (ppt)to parts per quadrillion by volume (ppq) undergo complicated microphysical and chemical processes in the lower atmosphere and play a significant role in climate by indirectly affecting the global radiative feedback through particle formation processes. This work presents the first detailed validation and interpretation of nitric acid (HNO$_{3}$), hydrogen cyanide (HCN)and some other relevant trace gases measured during the first two campaign deployments of the innovative Time-of-Flight Chemical Ionisation Mass Spectrometer FunMass. The two campaigns span science objectives as versatile as upper tropospheric and lower stratospheric processes above the Asian Monsoon region for the 2017 StratoClim campaign and the nighttime oxidation of isoprene for the 2018 NO$_{3}$-Isoprene campaign. The Asian Summer Monsoon (ASM) is the dominant circulation system in boreal summer. During high monsoon season, air in the highly polluted Asian boundary is rapidly transported into the Upper Troposphere and Lower Stratosphere (UTLS) by strong convective activities, where it is horizontally retained in the Asian Monsoon Anticyclone (AMA). With the upwelling motion inside the upper part of the AMA, these air pollutants can enter the global stratosphere, potentially affecting the worldwide climate. During the StratoClim aircraft campaign from Kathmandu, Nepal, in July and August 2017, FunMass was deployed onboard the high-altitude research aircraft M55-Geophysica. On August 6 and 8 of the campaign, the first two successful high spatial and temporal resolution in-situ measurements of gaseous HNO$_{3}$ and HCN with high spatial and temporal resolution were carried out inside the AMA. The atmospheric concentrations of HNO$_{3}$ and HCN were calibrated with reference to gravimetrically controlled permeation devices. HNO$_{3}$ was further referred to ion-chromatographic analyses. The in-situ measurements show a good agreement with satellite observations, i.e. HNO$_{3}$ from Aura-MLS and HCN from ACE-FTS. Tracer correlations have been studied with CO and O$_{3}$ obtained by the airborne instruments COLD and FOZAN, respectively. The HCN observations show significant vertical and horizontal signatures within the AMA which have been analysed by backward trajectory analyses employing the Lagrangian models TRACZILLA and CLaMS. Some of the structures are consistent with the CO measurements indicating quite recent convective events while some segments show CO enhancements without obvious HCN features, which is attributed to different origin regions. Measurements in both flights point to the existence of a layer with enhanced HCN at $\sim$ 365 K potential temperature level which probably is the main convective outflow layer. [...]

Note: Dissertation, Universität Wuppertal, 2020

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Contributing Institute(s):

1. Stratosphäre (IEK-7)

Research Program(s):

1. 244 - Composition and dynamics of the upper troposphere and middle atmosphere (POF3-244) (POF3-244)

Appears in the scientific report 2021

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