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Titel |
A horizontal mobile measuring system for atmospheric quantities |
VerfasserIn |
J. Hübner, J. Olesch, H. Falke, F. X. Meixner, T. Foken |
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 ; 7, no. 9 ; Nr. 7, no. 9 (2014-09-16), S.2967-2980 |
Datensatznummer |
250115899
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Publikation (Nr.) |
copernicus.org/amt-7-2967-2014.pdf |
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Zusammenfassung |
A fully automatic horizontal mobile measuring system (HMMS) for atmospheric
quantities has been developed. The HMMS is based on the drive mechanism of
a garden railway system and can be installed at any location and along any
measuring track. In addition to meteorological quantities (temperature,
humidity and short-/long-wave down/upwelling radiation), HMMS also measures
trace gas concentrations (carbon dioxide and ozone). While sufficient spatial
resolution is a problem even for measurements on distributed towers, this
could be easily achieved with the HMMS, which has been specifically developed
to obtain higher information density about horizontal gradients in
a heterogeneous forest ecosystem. There, horizontal gradients of
meteorological quantities and trace gases could be immense, particularly at
the transition from a dense forest to an open clearing, with large impact on
meteorological parameters and exchange processes. Consequently, HMMS was
firstly applied during the EGER IOP3 project (ExchanGE processes in mountainous
Regions – Intense Observation Period 3) in the Fichtelgebirge
Mountains (SE Germany) during summer 2011. At a constant 1 m above
ground, the measuring track of the HMMS consisted of a straight line
perpendicular to the forest edge, starting in the dense spruce forest and
leading 75 m into an open clearing. Tags with bar codes, mounted every
metre on the wooden substructure, allowed (a) keeping the speed of the HMMS
constant (approx. 0.5 m s−1) and (b) operation of the HMMS in
a continuous back and forth running mode. During EGER IOP3, HMMS was
operational for almost 250 h. Results show that – due to considerably
long response times (between 4 and 20 s) of commercial
temperature, humidity and the radiation sensors – true spatial variations of
the meteorological quantities could not be adequately captured (mainly at the
forest edge). Corresponding dynamical (spatial) errors of the measurement
values were corrected on the basis of well-defined individual response times
of the sensors and application of a linear correction algorithm. Due to the
very short response times (≤ 1 s) of the applied commercial
CO2 and O3 analysers, dynamical errors for the trace gas data
were negligible and no corrections were done. |
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