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| Titel |
NMHC Climatology from Central European Mountain Observatories |
| VerfasserIn |
Christian Plaß-Dülmer, Stefan Reimann, Markus Wallasch, Sverre Solberg, Dieter Klemp, Patrice Coddeville, Emmanuel Mahieu |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250056240
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| Zusammenfassung |
| NMHC (non-methane hydrocarbons) are a major group of atmospheric trace gases with
impact on photochemical processes in the atmosphere, especially oxidant formation with
ozone being the most prominent of them, and contributions to SOA (secondary organic
aerosols). By this, they are coupled to climate issues via the oxidizing capacity of the
atmosphere, the greenhouse gas ozone and aerosol effects. NMHC monitoring was initiated
in Europe in the “Tropospheric Ozone Research” project (1988-1995), and it was continued
in EMEP and GAW (Global Atmosphere Watch) where it is an ongoing initiative
which recently has been reinforced (GAW Report 171). In this presentation we will
focus on time series from Central European mountain stations (46-49Ë N, 7-13Ë
E):
Hohenpeissenberg (985 m, DWD, Germany, 1998-ongoing), Rigi (1031 m, EMPA,
Switzerland, 2003-ongoing), Junfraujoch (3580 m, EMPA, Switzerland, 2000-ongoing, and
ULg (FTIR), Belgium, 1984-ongoing), Zugpitze (2650 m, UBA, Germany, 2000-ongoing),
Schauinsland (1205 m, FZ-Jülich (1989-94), and UBA, Germany, 2004-ongoing),
Brotjacklriegel (1016 m, UBA, Germany, 2000-2004), Donon (775 m, EMD, France,
1997-2007).
Most sites used weekly flask samples but also on-line measurements were carried out
with higher time resolution within the former TOR project and in the more recent time series
at Hohenpeissenberg, Rigi, and Jungfraujoch. All samples were analysed by GC.
Additionally to these GC measurements, a time series of column integrated acetylene and
ethane by FTIR (Fourier Transform InfraRed spectrometry) is available from Jungfraujoch,
from 1984 onwards. We focus here on time series of monthly averages of anthropogenic
hydrocarbons over the 1997-2009 time period. They show quite similar patterns among the
various stations over the whole period with pronounced seasonal cycles. Significantly lower
mixing ratios were measured at the highest elevated sites, the Zugspitze and Jungfraujoch.
Differences between the lower mountain sites (775-1200 m) are on first view surprisingly
small. Generally, the differences between the high altitude and the other mountain sites are
lowest in summer due to enhanced vertical mixing and thermal upslope winds.
Downward trends for anthropogenic hydrocarbons are very similar at the various
stations and are 2 %/yr for C2-C3 alkanes (+/- 1%), 3-6 %/yr for C4-C7 alkanes (+/-
2%), 2-3 %/yr for C2-C3 alkynes and ethene (+/- 2%), 4 % /yr for propene and
benzene (+/- 2%), and 5-10%/yr for toluene and xylenes (+/-3 and 5%, respectively). |
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