Articles | Volume 14, issue 1
https://doi.org/10.5194/cp-14-1-2018
https://doi.org/10.5194/cp-14-1-2018
Research article
 | 
03 Jan 2018
Research article |  | 03 Jan 2018

Effects of undetected data quality issues on climatological analyses

Stefan Hunziker, Stefan Brönnimann, Juan Calle, Isabel Moreno, Marcos Andrade, Laura Ticona, Adrian Huerta, and Waldo Lavado-Casimiro

Abstract. Systematic data quality issues may occur at various stages of the data generation process. They may affect large fractions of observational datasets and remain largely undetected with standard data quality control. This study investigates the effects of such undetected data quality issues on the results of climatological analyses. For this purpose, we quality controlled daily observations of manned weather stations from the Central Andean area with a standard and an enhanced approach. The climate variables analysed are minimum and maximum temperature and precipitation. About 40 % of the observations are inappropriate for the calculation of monthly temperature means and precipitation sums due to data quality issues. These quality problems undetected with the standard quality control approach strongly affect climatological analyses, since they reduce the correlation coefficients of station pairs, deteriorate the performance of data homogenization methods, increase the spread of individual station trends, and significantly bias regional temperature trends. Our findings indicate that undetected data quality issues are included in important and frequently used observational datasets and hence may affect a high number of climatological studies. It is of utmost importance to apply comprehensive and adequate data quality control approaches on manned weather station records in order to avoid biased results and large uncertainties.

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Short summary
Many data quality problems occurring in manned weather station observations are hardly detected with common data quality control methods. We investigated the effects of undetected data quality issues and found that they may reduce the correlation coefficients of station pairs, deteriorate the performance of data homogenization methods, increase the spread of individual station trends, and significantly bias regional trends. Applying adequate quality control approaches is of utmost importance.