Statistical-topographical mapping of rainfall over mountainous terrain with the β-IDW approach
- 1Karlsruhe Institute of Technology, Institute of Water Resources and River Basin Management, Hydrology, Karlsruhe, Germany (jan.wienhoefer@kit.edu)
- 2Technical University of Munich, Chair of Hydrology and River Basin Management, Munich, Germany
- 3Deutscher Wetterdienst DWD, Offenbach, Germany
We present a robust approach for quantitative precipitation estimation (QPE) for water resources management in mountainous catchments, where rainfall sums and variability are correlated with orographic elevation, but density of rain gauges does not allow for advanced geostatistical interpolation of rainfall fields.
Key of the method is modelling rainfall at unobserved locations by their elevation-dependent expected daily mean, and a daily fluctuation which is determined by spatial interpolation of the residuals of neighbouring rain gauges, which are scaled according to the elevation difference. The scaling factor is defined as the ratio of covariance and variance, in analogy to the "beta" used in economics.
The approach is illustrated for the Chirilu catchments (Chillón, Rímac, Lurín) in the Andes near Lima, Peru. The results are compared to conventional IDW interpolation and a merged national rainfall product. The method results in QPE that are better matching with observed discharges. The β-IDW approach thus provides a robust and flexible means to estimate rainfall input to mesoscale mountainous catchments.
How to cite: Wienhöfer, J., Alcamo, L., Bondy, J., and Zehe, E.: Statistical-topographical mapping of rainfall over mountainous terrain with the β-IDW approach, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-13993, https://doi.org/10.5194/egusphere-egu23-13993, 2023.
