In:
Atmospheric Chemistry and Physics, Copernicus GmbH, Vol. 21, No. 10 ( 2021-05-27), p. 8213-8232
Kurzfassung:
Abstract. Measurements of the pollution trace gases ethane (C2H6), ethyne
(C2H2), formic acid (HCOOH), and peroxyacetyl nitrate (PAN) were
performed in the North Atlantic upper troposphere and lowermost stratosphere
(UTLS) region with the airborne limb imager GLORIA (Gimballed Limb Observer
for Radiance Imaging of the Atmosphere) with high spatial resolution down to
cloud top. Observations were made during flights with the German research
aircraft HALO (High Altitude and LOng Range Research Aircraft) in the frame
of the WISE (Wave-driven ISentropic Exchange) campaign, which was carried
out in autumn 2017 from Shannon (Ireland) and Oberpfaffenhofen (Germany).
Enhanced volume mixing ratios (VMRs) of up to 2.2 ppbv C2H6, 0.2
ppbv C2H2, 0.9 ppbv HCOOH, and 0.4 ppbv PAN were detected during
the flight on 13 September 2017 in the upper troposphere and around the
tropopause above the British Isles. Elevated quantities of PAN were measured
even in the lowermost stratosphere (locally up to 14 km), likely reflecting
the fact that this molecule has the longest lifetime of the four species
discussed herein. Backward trajectory calculations as well as global
three-dimensional Chemical
Lagrangian Model of the Stratosphere (CLaMS) simulations with artificial tracers of air mass
origin have shown that the main sources of the observed pollutant species
are forest fires in North America and anthropogenic pollution in South Asia and
Southeast Asia uplifted and moved within the Asian monsoon anticyclone (AMA)
circulation system. After release from the AMA, these species or their
precursor substances are transported by strong tropospheric winds over large
distances, depending on their particular atmospheric lifetime of up to
months. Observations are compared to simulations with the atmospheric models
EMAC (ECHAM5/MESSy Atmospheric Chemistry) and CAMS (Copernicus Atmosphere
Monitoring Service). These models are qualitatively able to reproduce the
measured VMR enhancements but underestimate the absolute amount of the
increase. Increasing the emissions in EMAC by a factor of 2 reduces the
disagreement between simulated and measured results and illustrates the
importance of the quality of emission databases used in chemical models.
Materialart:
Online-Ressource
ISSN:
1680-7324
DOI:
10.5194/acp-21-8213-2021
Sprache:
Englisch
Verlag:
Copernicus GmbH
Publikationsdatum:
2021
ZDB Id:
2092549-9
ZDB Id:
2069847-1