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| Titel |
A laboratory evaluation of the influence of weighing gauges performance on extreme events statistics |
| VerfasserIn |
Matteo Colli, Luca Lanza |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250096379
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| Publikation (Nr.) |
 EGU/EGU2014-11879.pdf |
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| Zusammenfassung |
| The effects of inaccurate ground based rainfall measurements on the information derived
from rain records is yet not much documented in the literature. La Barbera et al. (2002)
investigated the propagation of the systematic mechanic errors of tipping bucket type rain
gauges (TBR) into the most common statistics of rainfall extremes, e.g. in the assessment of
the return period T (or the related non-exceedance probability) of short-duration/high
intensity events. Colli et al. (2012) and Lanza et al. (2012) extended the analysis to a 22-years
long precipitation data set obtained from a virtual weighing type gauge (WG). The artificial
WG time series was obtained basing on real precipitation data measured at the meteo-station
of the University of Genova and modelling the weighing gauge output as a linear dynamic
system. This approximation was previously validated with dedicated laboratory experiments
and is based on the evidence that the accuracy of WG measurements under real
world/time varying rainfall conditions is mainly affected by the dynamic response of the
gauge (as revealed during the last WMO Field Intercomparison of Rainfall Intensity
Gauges).
The investigation is now completed by analyzing actual measurements performed by two
common weighing gauges, the OTT Pluvio2 load-cell gauge and the GEONOR T-200
vibrating-wire gauge, since both these instruments demonstrated very good performance
under previous constant flow rate calibration efforts. A laboratory dynamic rainfall generation
system has been arranged and validated in order to simulate a number of precipitation
events with variable reference intensities. Such artificial events were generated
basing on real world rainfall intensity (RI) records obtained from the meteo-station
of the University of Genova so that the statistical structure of the time series is
preserved.
The influence of the WG RI measurements accuracy on the associated extreme events
statistics is analyzed by comparing the original intensity-duration-frequency (IDF) curves
with those obtained from the measuring of the simulated rain events.
References:
Colli, M., L.G. Lanza, and P. La Barbera, (2012). Weighing gauges measurement errors and
the design rainfall for urban scale applications, 9th International Workshop On Precipitation
In Urban Areas, 6-9 December, 2012, St. Moritz, Switzerland
Lanza, L.G., M. Colli, and P. La Barbera (2012). On the influence of rain gauge performance
on extreme events statistics: the case of weighing gauges, EGU General Assembly 2012,
April 22th, Wien, Austria
La Barbera, P., L.G. Lanza, and L. Stagi, (2002). Influence of systematic mechanical errors of
tipping-bucket rain gauges on the statistics of rainfall extremes. Water Sci. Techn., 45(2),
1-9. |
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