Advances in Geosciences www.adv-geosci.net 1680-7340 1680-7359 25 Precipitation: Measurement, Climatology, Remote Sensing, and Modeling (EGU Session 2009) 2010 10.5194/adgeo-25-37-2010 http://www.adv-geosci.net/25/37/2010/ http://www.adv-geosci.net/25/37/2010/adgeo-25-37-2010.html http://www.adv-geosci.net/25/37/2010/adgeo-25-37-2010.pdf 37 44 2010-03-09 Analysis of highly accurate rain intensity measurements from a field test site L. G. Lanza luca.lanza@unige.it E. Vuerich I. Gnecco Department of Construction, Environmental and Territorial Engineering, University of Genova, 1 Montallegro, 16145 Genova, Italy Italian Meteorological Service – Centre of Meteorological Experimentations (ReSMA), km 20, 100 Braccianese Claudia, 00062 Bracciano, Italy In the course of the recent WMO international instrument intercomparison in the field and the associated specific laboratory tests, highly accurate rainfall intensity measurements have been collected and made available for scientific investigation. The resulting high quality data set (contemporary one-minute rainfall intensity data from 26 gauges based on various measuring principles) constitutes an important resource to provide insights into the expected behaviour of rain intensity gauges in operational conditions and further useful information for National Meteorological Services and other users. A few aspects of the analysis of one-minute resolution rain intensity measurements are discussed in this paper, focusing on the observed deviations from a calculated reference intensity based on four pit gauges. Results from both catching and non-catching type gauges are discussed in relation with suitable tolerance limits obtained as a combination of the estimated uncertainty of the reference intensity and the WMO accuracy limits for rainfall intensity measurements. It is shown that suitably post-processed weighing gauges and tipping-bucket rain gauges had acceptable performance, while none of the non-catching rain gauges agreed well with the reference. JCGM: Evaluation of measurement data – Guide to the expression of uncertainty in measurement. Joint Committee for Guides in Metrology, First edition, September 2008. Keefer, T. O., Unkrich, C. L., Smith, J. R., Goodrich, D. C., Moran, M. S., and Simanton, J. R.: An event-based comparison of two types of automated-recording, weighing bucket rain gauges, Water Resour. Res., 44, W05S12, doi:10.1029/2006WR005841, 2008. La Barbera, P., Lanza, L. G., and Stagi, L.: Influence of systematic mechanical errors of tipping-bucket rain gauges on the statistics of rainfall extremes, Water Sci. Technol., 45(2), 1–9, 2002. Lanza, L. G., Leroy, M., Alexandropoulos, C., Stagi, L., and Wauben, W.: WMO Laboratory Intercomparison of Rainfall Intensity Gauges – Final Report, IOM Report No 84, WMO/TD No 1304, 2005. Lanza, L. G. and Stagi, L.: Certified accuracy of rainfall data as a standard requirement in scientific investigations, Adv. Geosci., 16, 43–48, 2008. Lanza, L. G. and Stagi, L.: High resolution performances of catching type rain gauges from the laboratory phase of the WMO Field Intercomparison of Rain Intensity Gauges, Atmos. Res., 94(4), 555–563, 2009. Lanza, L. G. and Vuerich, E.: The WMO Field Intercomparison of Rain Intensity Gauges, Amos. Res., 94(4), 534–543, 2009. Michaelides, S.: Preface of the Special Issue on Precipitation Measurement, Remote Sensing, Climatology and Modeling, Atmos. Res., 94(4), 511, 2009. Molini, A., Lanza, L. G., and La Barbera, P.: Improving the accuracy of tipping-bucket rain records by disaggregation techniques, Atmos. Res., 77, 203–217, 2005a. Molini, A., Lanza, L. G., and La Barbera, P.: The impact of tipping-bucket raingauge measurement errors on design rainfall for urban-scale applications, Hydrol. Process., 19, 1073–1088, 2005b. Pavlyukov, Yu. B.: Precipitation measurement with automated tipping-bucket rain gauges, Russian Meteorol. Hydrol., 32(11), 711–718, 2007. Ren, Z. and Li, M.: Errors and correction of precipitation measurements in China, Adv. Atmos. Sci., 24(3), 449–458, 2007. Rodriguez J., Vos F., Below R., and Guha-Sapir, D.: Annual Disaster Statistical Review: the Numbers and Trends. Centre for Research on the Epidemiology of Disasters, Jacoffset Printers, Melin (Belgium), 2009. Tokay, A., Wolff, D. B., Wolff, K. R., and Bashor, P.: Rain Gauge and Disdrometer Measurements during the Keys Area Microphysics Project (KAMP), J. Atmos. Ocean. Tech., 20, 1460–1477, 2003. Vuerich, E., Monesi, C., Lanza, L. G., Stagi, L., and Lanzinger, E.: WMO Field Intercomparison of Rainfall Intensity Gauges. World Meteorological Organisation – Instruments and Observing Methods Rep. No 99, WMO/TD No 1504, 2009a. Vuerich, E., Lanza, L. G., and Stagi, L.: WMO Field Intercomparison of Rainfall Intensity Gauges: the field calibration (Italy, 2007–2009), in: Rainfall in the urban context: forecasting, risk and climate change, Proc. 8th International Workshop on Precipitation in Urban Areas. St. Moritz, Switzerland, 10–13~December~2009, 268–272 (published on CD-ROM), 2009b. 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