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Titel |
Continuous measurements of greenhouse gases and atmospheric oxygen at the Namib Desert Atmospheric Observatory |
VerfasserIn |
E. J. Morgan, J. V. Lavrič, T. Seifert, T. Chicoine, A. Day, J. Gómez, R. Logan, J. Sack, T. Shuuya, E. G. Uushona, K. Vincent, U. Schultz, E.-G. Brunke, C. Labuschagne, R. L. Thompson, S. Schmidt, A. C. Manning, M. Heimann |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1867-1381
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Digitales Dokument |
URL |
Erschienen |
In: Atmospheric Measurement Techniques ; 8, no. 6 ; Nr. 8, no. 6 (2015-06-01), S.2233-2250 |
Datensatznummer |
250116417
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Publikation (Nr.) |
copernicus.org/amt-8-2233-2015.pdf |
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Zusammenfassung |
A new coastal background site has been established for observations of
greenhouse gases (GHGs) in the central Namib Desert at Gobabeb, Namibia. The
location of the site was chosen to provide observations for a data-poor
region in the global sampling network for GHGs. Semi-automated continuous
measurements of carbon dioxide, methane, nitrous oxide, carbon monoxide,
atmospheric oxygen, and basic meteorology are made at a height of 21 m a.g.l.,
50 km from the coast at the northern border of the Namib Sand Sea.
Atmospheric oxygen is measured with a differential fuel cell analyzer (DFCA).
Carbon dioxide and methane are measured with an early-model cavity ring-down
spectrometer (CRDS); nitrous oxide and carbon monoxide are measured with an
off-axis integrated cavity output spectrometer (OA-ICOS). Instrument-specific
water corrections are employed for both the CRDS and OA-ICOS instruments in
lieu of drying. The performance and measurement uncertainties are discussed
in detail. As the station is located in a remote desert environment, there
are some particular challenges, namely fine dust, high diurnal temperature
variability, and minimal infrastructure. The gas handling system and
calibration scheme were tailored to best fit the conditions of the site. The
CRDS and DFCA provide data of acceptable quality when base requirements for
operation are met, specifically adequate temperature control in the
laboratory and regular supply of electricity. In the case of the OA-ICOS
instrument, performance is significantly improved through the implementation
of a drift correction through frequent measurements of a reference cylinder. |
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