Pyranometer offsets triggered by ambient meteorology: insights from laboratory and field experiments

This study investigates the effects of ambient meteorology on the accuracy of radiation (<i>R</i>) measurements performed with pyranometers contained in various heating and ventilation systems (HV-systems). It focuses particularly on instrument offsets observed following precipitation ev...

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Main Authors: S. M. Oswald, H. Pietsch, D. J. Baumgartner, P. Weihs, H. E. Rieder
Format: Article
Language:English
Published: Copernicus Publications 2017-03-01
Series:Atmospheric Measurement Techniques
Online Access:http://www.atmos-meas-tech.net/10/1169/2017/amt-10-1169-2017.pdf
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author S. M. Oswald
H. Pietsch
D. J. Baumgartner
P. Weihs
H. E. Rieder
author_facet S. M. Oswald
H. Pietsch
D. J. Baumgartner
P. Weihs
H. E. Rieder
author_sort S. M. Oswald
collection DOAJ
description This study investigates the effects of ambient meteorology on the accuracy of radiation (<i>R</i>) measurements performed with pyranometers contained in various heating and ventilation systems (HV-systems). It focuses particularly on instrument offsets observed following precipitation events. To quantify pyranometer responses to precipitation, a series of controlled laboratory experiments as well as two targeted field campaigns were performed in 2016. The 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 of laboratory experiments showed that precipitation triggers zero offsets of −4 W m<sup>−2</sup> or more, independent of the HV-system. Similar offsets were observed in field experiments under ambient environmental conditions, indicating a clear exceedance of BSRN (Baseline Surface Radiation Network) targets following precipitation events. All pyranometers required substantial time to return to their initial signal states after the simulated precipitation events. Therefore, for BSRN-class measurements, the recommendation would be to flag the radiation measurements during a natural precipitation event and 90 min after it in nighttime conditions. Further daytime experiments show pyranometer offsets of 50 W m<sup>−2</sup> or more in comparison to the reference system. As they show a substantially faster recovery, the recommendation would be to flag the radiation measurements within a natural precipitation event and 10 min after it in daytime conditions.
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spelling doaj.art-c2e300b2503c4c368898fb0ee47a50902022-12-21T18:02:02ZengCopernicus PublicationsAtmospheric Measurement Techniques1867-13811867-85482017-03-011031169117910.5194/amt-10-1169-2017Pyranometer offsets triggered by ambient meteorology: insights from laboratory and field experimentsS. M. Oswald0H. Pietsch1D. J. Baumgartner2P. Weihs3H. E. Rieder4Wegener Center for Climate and Global Change, Graz, AustriaInstitute for Geophysics, Astrophysics and Meteorology, Institute of Physics, Graz, AustriaKanzelhöhe Observatory for Solar and Environmental Research, Graz, AustriaInstitute of Meteorology, University of Natural Resources and Life Sciences (BOKU), Vienna, AustriaWegener Center for Climate and Global Change, Graz, AustriaThis study investigates the effects of ambient meteorology on the accuracy of radiation (<i>R</i>) measurements performed with pyranometers contained in various heating and ventilation systems (HV-systems). It focuses particularly on instrument offsets observed following precipitation events. To quantify pyranometer responses to precipitation, a series of controlled laboratory experiments as well as two targeted field campaigns were performed in 2016. The 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 of laboratory experiments showed that precipitation triggers zero offsets of −4 W m<sup>−2</sup> or more, independent of the HV-system. Similar offsets were observed in field experiments under ambient environmental conditions, indicating a clear exceedance of BSRN (Baseline Surface Radiation Network) targets following precipitation events. All pyranometers required substantial time to return to their initial signal states after the simulated precipitation events. Therefore, for BSRN-class measurements, the recommendation would be to flag the radiation measurements during a natural precipitation event and 90 min after it in nighttime conditions. Further daytime experiments show pyranometer offsets of 50 W m<sup>−2</sup> or more in comparison to the reference system. As they show a substantially faster recovery, the recommendation would be to flag the radiation measurements within a natural precipitation event and 10 min after it in daytime conditions.http://www.atmos-meas-tech.net/10/1169/2017/amt-10-1169-2017.pdf
spellingShingle S. M. Oswald
H. Pietsch
D. J. Baumgartner
P. Weihs
H. E. Rieder
Pyranometer offsets triggered by ambient meteorology: insights from laboratory and field experiments
Atmospheric Measurement Techniques
title Pyranometer offsets triggered by ambient meteorology: insights from laboratory and field experiments
title_full Pyranometer offsets triggered by ambient meteorology: insights from laboratory and field experiments
title_fullStr Pyranometer offsets triggered by ambient meteorology: insights from laboratory and field experiments
title_full_unstemmed Pyranometer offsets triggered by ambient meteorology: insights from laboratory and field experiments
title_short Pyranometer offsets triggered by ambient meteorology: insights from laboratory and field experiments
title_sort pyranometer offsets triggered by ambient meteorology insights from laboratory and field experiments
url http://www.atmos-meas-tech.net/10/1169/2017/amt-10-1169-2017.pdf
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