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| Titel |
Influence of ambient meteorology on the accuracy of radiation measurements: insights from field and laboratory experiments |
| VerfasserIn |
Sandro M. Oswald, Helga Pietsch, Dietmar J. Baumgartner, Harald E. Rieder |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250123795
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| Publikation (Nr.) |
 EGU/EGU2016-3103.pdf |
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| Zusammenfassung |
| A precise knowledge of the surface energy budget, which includes the solar and terrestrial
radiation fluxes, is needed to accurately characterize the global energy balance which is
largely determining Earth’s climate. To this aim national and global monitoring
networks for surface radiative fluxes have been established in recent decades. The most
prominent among these networks is the so-called Baseline Surface Radiation Network
(BSRN) operating under the auspices of the World Climate Research Programme
(WCRP) (Ohmura et al., 1998). National monitoring networks such as the Austrian
RADiation Monitoring Network (ARAD), which has been established in 2010 by a
consortium of the Central Agency of Meteorology and Geodynamics (ZAMG),
the University of Graz, the University of Innsbruck, and the University of Natural
Resources and Applied Sciences, Vienna (BOKU), orient themselves on BSRN
standards (McArthur, 2005). ARAD comprises to date five sites (Wien Hohe Warte,
Graz/University, Innsbruck/University, Kanzelhöhe Observatory and Sonnblick (which is
also a BSRN site)) and aims to provide long-term monitoring of radiation budget
components at highest accuracy and to capture the spatial patterns of radiation climate in
Austria (Olefs et al., 2015). Given the accuracy requirement for the local monitoring
of radiative fluxes instrument offsets, triggered by meteorological factors and/or
instrumentation, pose a major challenge in radiation monitoring. Within this study we
investigate effects of ambient meteorology on the accuracy of radiation measurements
performed with pyranometers contained in various heating/ventilation systems
(HV-systems), all of which used in regular operation within the ARAD network. We focus
particularly on instrument offsets observed following precipitation events. To quantify
pyranometer responses to precipitation we performed a series of controlled laboratory
experiments as well as targeted field campaigns in 2015 and 2016. Our results indicate that
precipitation (as simulated by spray-tests or observed under ambient conditions)
significantly affects the thermal environment of the instruments and thus their stability.
Statistical analyses during nighttime conditions showed that precipitation triggers zero
offsets of 4 W/m2 or more, depending on the HV-system and prevailing ambient
conditions (i.e., air temperature, wind), indicating a clear exceedance of BSRN
targets.
References:
McArthur L. J. B.: World Climate Research Programme-Baseline Surface Radiation
Network (BSRN) - Operations Manual Version 2.1, Experimental Studies Division,
Atmospheric Environment Service, Downsview, Ontario, Canada, 2005.
Olefs M., Baumgartner D. J., Obleitner F., Bichler C., Foelsche U., Pietsch H., Rieder H. E.,
Weihs P., Geyer F., Haiden T., Schöner W.: The Austrian radiation monitoring network ARAD
- best practice and added value, Atmospheric Measurement Techniques Discussions, 8:
10663-10710, 2015.
Ohmura A., Dutton E. G., Forgan B., Frohlich C., Gilgen H., Hegner H., Heimo A., Stephens
G. L., König-Langlo G., McArthur B., Müller G., Philipona R., Pinker R., Whitlock C. H.,
Dehne K., Wild M.: Baseline surface radiation network (bsrn/wcrp): new precision
radiometry for climate research, Bulletin of the American Meteorological Society, 79(10):
2115-2136, 1998. |
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