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High resolution performances of catching type rain gauges from the laboratory phase of the WMO Field Intercomparison of Rain Intensity gauges
No full text
Sulla misura dell'intensità di pioggia con pluviometri a vaschette basculanti: errori sistematici e statistiche dei valori estremi
No full textImproving the accuracy of operational tipping-bucket rain gauges by calibration techniques
No full textCertified accuracy of rainfall data as a standard requirement in scientific investigations.
No full textThis paper elaborates on the rationale behind the
proposed standard limits for the accuracy of rainfall intensity
measurements obtained from tipping-bucket and other types
of rain gauges. Indeed, based on experimental results obtained
in the course of international instrument Intercomparison
initiatives and specific laboratory tests, it is shown here
that the accuracy of operational rain gauges can be reduced
to the limits of ±1% after proper calibration and correction.
This figure is proposed as a standard accuracy requirement
for the use of rain data in scientific investigations. This limit
is also proposed as the reference accuracy for operational
rain gauge networks in order to comply with quality assurance
systems in meteorological observations
Non-parametric error distribution analysis from the laboratory calibration of various rainfall intensity gauges
No full textThe analysis of counting and catching errors of both catching and non-catching types of rain intensity
gauges was recently possible over a wide variety of measuring principles and instrument design
solutions, based on the work performed during the recent Field Intercomparison of Rainfall Intensity
Gauges promoted by World Meteorological Organization (WMO). The analysis reported here concerns
the assessment of accuracy and precision of various types of instruments based on extensive
calibration tests performed in the laboratory during the first phase of this WMO Intercomparison.
The non-parametric analysis of relative errors allowed us to conclude that the accuracy of the
investigated RI gauges is generally high, after assuming that it should be at least contained within the
limits set forth by WMO in this respect. The measuring principle exploited by the instrument is
generally not very decisive in obtaining such good results in the laboratory. Rather, the attention paid
by the manufacturer to suitably accounting and correcting for systematic errors and time-constant
related effects was demonstrated to be influential. The analysis of precision showed that the
observed frequency distribution of relative errors around their mean value is not indicative of an
underlying Gaussian population, being much more peaked in most cases than can be expected from
samples extracted from a Gaussian distribution. The analysis of variance (one-way ANOVA), assuming
the instrument model as the only potentially affecting factor, does not confirm the hypothesis of a
single common underlying distribution for all instruments. Pair-wise multiple comparison analysis
revealed cases in which significant differences could be observed
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