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| Titel |
Continuous atmospheric measurements of COS, CO2, CO and H2O at the Lutjewad tower in the Netherlands |
| VerfasserIn |
Linda M. J. Kooijmans, Huilin Chen, Nelly A. M. Uitslag, Mark S. Zahniser, David D. Nelson, Stephen A. Montzka |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250108899
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| Publikation (Nr.) |
 EGU/EGU2015-8735.pdf |
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| Zusammenfassung |
| A critical step in carbon modelling studies is to resolve both Gross Primary Production (GPP)
and Respiration (Re). Although several methods have been proposed to partition the Net
Ecosystem Exchange (NEE) into GPP and Re, large uncertainties still exist in quantifying
these fluxes. As a potential solution to this problem carbonyl sulfide (COS) was
proposed as a tracer for photosynthetic CO2 uptake as it is also taken up by plants, but
not being released. Although atmospheric COS measurements have been made
since a few decades, there has not been any atmospheric measurement station that
performs continuous in situ measurements of COS on the long term. For this reason,
the source and sink terms of COS are poorly known, which limits the ability of
employing COS as a tracer for GPP. In July 2014 we set up a quantum cascade
laser (QCL) spectrometer (Aerodyne Research Inc., MA, USA) for continuous and
simultaneous measurements of COS, CO2, CO and H2O at the Lutjewad atmospheric
monitoring station (60 m, 6°21’E, 53°24’N, 1 m a.s.l) in the Netherlands. The
so called QCL mini monitor was initially configured to measure COS, CO2 and
H2O. We extended the frequency range of the laser to include measurements of CO
(2050.854 cm-1). The short-term precision of the analyser is 2.5 ppt for COS,
0.03 ppm for CO2 and 0.11 ppb for CO (1 Hz). Calibrations were necessary on
time scales of an hour to correct for instrument response drift. Furthermore, we
assessed the correction for water vapour interference applied by the instrument
control software and present an alternative water vapour correction for CO2. The
accuracy of the instrument for measurements of CO2 and CO is evaluated with a
cavity ring-down spectrometer (Picarro Inc., CA, USA). Besides that, we tested the
ability to do flask sample measurements with the QCL analyser for assessing the
stability of the COS scale, and for controlling the quality of the COS measurements
from our Lutjewad station. We will do tracer-tracer (COS, Radon, CO, and CO2)
correlation studies to estimate COS fluxes and to understand the sources and sinks of
COS. |
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