Design precipitation intensities

From the water management point of view, it is important to know the probability of the occurrence of heavy rains, which is expressed by the so-called design precipitation intensities. We have been solving this issue since 2015 in cooperation with the Czech Technical University and other partners. As part of the QJ1520265 project, we compiled six synthetic hyetograms based on adjusted radar; the hyetograms represent model curves of precipitation intensities in the Czech Republic during a six-hour period (Müller et al., 2018). This approach has become the cornerstone of a certified methodology for designing small water management structures in the landscape (Kavka, Müller et al, 2018). Based on the percentage of synthetic hyetograms, we then expressed the probability of different time structures of precipitation intensities within the Czech territory (Kašpar et al., 2021).

Six synthetic hyetograms, depicted together with selected cumulative hyetograms during selected heavy precipitation events. Source: Müller et al. (2018).

Representation of six types of precipitation time structures within sets of heavy precipitation events of the given return periods at different altitudes of the Czech Republic. Source: Kašpar et al. (2021).

Using adjusted radar data, we also refined the climatology of sub-daily heavy precipitation intensities in the Czech Republic (Bližňák et al., 2018). In order to extend the knowledge of extreme events before radar measurements have started, we compiled a methodology for the reconstruction of historical precipitation events using a numerical weather prediction model (Bližňák et al., 2019) and applied it to selected events of heavy precipitation (Bližňák et al., 2021).

Comparison between maximum 1-hour and 24-hour precipitation totals, recorded during 10 years in individual places in Czechia. Source: Bližňák et al. (2018).

Relationship between the reconstructed and the observed course of selected precipitation events. Source: Bližňák et al. (2019).

Our research of design precipitation intensities continues within the currently solved projects. In cooperation with the Czech Hydrometeorological Institute in the project QK1910029, we refine estimates of design precipitation intensities for the Czech Republic; a novelty will be the determination of the design intensities for individual calendar months and the description of the statistical distribution of the values of antecedent precipitation totals. The SS01020366 project deals with the use of remote sensing tools for the analysis of the possible runoff response of river basins. The spatial aspect of the design precipitation intensities and their connection to other elements of the hydrological balance of river basins is given attention in the recently launched project ME08011 "PERUN".

  • Bližňák, V., Kašpar, M., Müller, M., Zacharov, P., 2021: Analysis and verification of reconstructed historical extreme precipitation events in an hourly resolution. Atmos. Res., 249, 105309.
  • Kašpar, M., Bližňák, V., Hulec, F., Müller, M., 2021: High-resolution spatial analysis of the variability in the subdaily rainfall time structure. Atmos. Res., 248, 105202.
  • Bližňák, V., Kašpar, M., Müller, M., Zacharov, P., 2019: Sub-daily temporal reconstruction of extreme precipitation events using NWP model simulations. Atmos. Res., 224, 65–80.
  • Bližňák, V., Kašpar, M., Müller, M., 2018: Radar-based summer precipitation climatology of the Czech Republic. Int. J. Climatol., 38, 677–691.
  • Kavka, P., Müller, M., Strouhal, L., Kašpar, M., Bližňák, V., Landa, M., Weyskrabová, L., Pavel, M., Dostál, T., 2018: Krátkodobé srážky pro hydrologické modelování a navrhování drobných vodohospodářských staveb v krajině. České vysoké učení technické, Ústav fyziky atmosféry AV ČR, v.v.i., Sweco Hydroprojekt, a.s., Praha, 80 s.
  • Müller, M., Bližňák, V., Kašpar, M., 2018: Analysis of rainfall time structures on a scale of hours. Atmos. Res., 211, 38–51.