Advances in Science and Research www.adv-sci-res.net 1992-0628 1992-0636 3 8th EMS Annual Meeting and 7th European Conference on Applied Climatology 2008 2009 10.5194/asr-3-23-2009 http://www.adv-sci-res.net/3/23/2009/ http://www.adv-sci-res.net/3/23/2009/asr-3-23-2009.html http://www.adv-sci-res.net/3/23/2009/asr-3-23-2009.pdf 23 26 2009-04-07 Data quality control and homogenization of air temperature and precipitation series in the area of the Czech Republic in the period 1961–2007 P. Štěpánek petr.stepanek@chmi.cz P. Zahradníček P. Skalák Czech Hydrometeorological Institute, Regional Office Brno, Czech Republic Quality control and homogenization has to be undertaken prior to any data analysis in order to eliminate any erroneous values and non climatic biases in time series. In this work we describe and then apply our own approach to data quality control, combining several methods: (i) by applying limits derived from interquartile ranges (ii) by analyzing difference series between candidate and neighbouring stations and (iii) by comparing the series values tested with "expected'' values &ndash; technical series created by means of statistical methods for spatial data (e.g. IDW, kriging). <br><br> Because of the presence of noise in series, statistical homogeneity tests render results with some degree of uncertainty. In this work, the use of various statistical tests and reference series made it possible to increase considerably the number of homogeneity test results for each series and thus to assess homogeneity more reliably. Inhomogeneities were corrected on a daily scale. <br><br> These methodological approaches are demonstrated by use of the daily data of air temperature and precipitation measured in the area of the Czech Republic. Series were processed by means of developed ProClimDB and AnClim software (<a href="http://www.climahom.eu" target="_blank">http://www.climahom.eu</a>). Alexandersson, A.: A homogeneity test applied to precipitation data, J. Climatol., 6, 661–675, 1986. Alexandersson, A.: Homogenity testing, multiple breaks and trends, in: Proc. 6th Int. Meeting on Stat. Climatology, Galway, Ireland, 439–441, 1995. Brandsma, T.: Weather-type dependent homogenization of daily Zwanenburg/De Bilt temperature series, http://www.met.hu/omsz.php?almenu_id=omsz&pid=seminars&pri=6&mpx=1&sm0=0&tfi=brandsma, 2000. Della-Marta, P. M. and Wanner, H.: A Method of Homogenizing the Extremes and Mean of Daily Temperature Measurements, J. Climate, 19, 4179–4197, 2006. Déqué, M.: Frequency of precipitation and temperature extremes over France in an anthropogenic scenario: model results and statistical correction according to observed values, Global Planet. Change, 57, 16–26, 2007. Easterling, D. R. and Peterson, T. C.: A new method for detecting undocumented discontinuities in climatological time series, Int. J. Climatol., 15, 369–377, 1995. Peterson, T. C.: Homogeneity adjustments of in situ atmospheric climate data: a review, Int. J. Climatol., 18, 1493–1517, 1998. Petrovic, P.: Detecting of inhomogeneities in time series using Real Precision Metod, in: Fourth seminar for homogenization and quality control in climatological databases (Budapest, Hungary, 6–10 October 2003), WCDMP-No. 56., WMO, Geneva, 79–88, 2004. Potter, K. W.: Illustration of a New Test for Detecting a Shift in Mean in Precipitation Series, Mon. Weather Rev., 109, 2040–2045, 1981. Štěpánek, P., \vRezníčková, L., and Brázdil, R.: Homogenization of daily air pressure and temperature series for Brno (Czech Republic) in the period 1848–2005, in: Proceedings of the Fifth seminar for homogenization and quality control in climatological databases (Budapest, 29 May–2 June 2006), WCDMP, WMO, Genova, CD-ROM, 2008. Štěpánek, P.: ProClimDB – software for processing climatological datasets, CHMI, regional office Brno, http://www.climahom.eu/ProcData.html, 2008. Trewin, B. C. and Trevitt, A. C. F.: The development of composite temperature records, Int. J. Climatol., 16, 1227–1242, 1996. Vincent, L. A., Zhang, X., Bonsal, B. R., and Hogg, W. D.: Homogenization of daily temperatures over Canada, J. Climate, 15, 1322–1334, 2002. Wijngaard, J. B., Klein Tank, A. M. G., and Können, G. P.: Homogenity of 20th century European daily temperature and precipitation series, Int. J. Climatol., 23, 679–692, 2003.