Because urban hydrological applications require rainfall data at fine spatial and temporal scales, which are not always available (e.g. when applying the course scale national C-band radar network data), spatial and temporal downscaling or disaggregation methods have been studied and advanced.

Click on the links below to access information (scientific papers) on these methods and evaluations.

• Multifractal methods for spatio-temporal downscaling: these methods rely on the assumption that rainfall is generated through a multiplicative cascade process that distributes intensity from large scale structures to small scale. It relies on the scale-invariance properties of the Navier-Stokes equations governing atmospheric behaviour. They were validated with the help of dense network of point measurement devices. They were developed by partners from ENPC during the RainGain project. Additional information:

  • Gires, A., Tchiguirinskaia, I., Schertzer, D., Schellart, A., Berne, A., Lovejoy, S. (2014). ‘Definition and implementation of innovative comparison tools between radar and rain gauge rainfall measurement’. Atmospheric Research, 138, 125-138

• Method for temporal downscaling: new method for temporal interpolation of radar data with coarse temporal resolution (e.g. 5 minutes) to finer temporal resolutions (e.g. 1 minutes), based/depending on the available rain gauge data. This was developed by partners from KU Leuven and Imperial College London. Additional information:

  • Wang, L-P., Ochoa-Rodriguez, S., Van Assel, J., Pina, R.D., Kroll, S., Pessemier, M., Willems, P., Onof, C. (2015), ‘Enhancement of radar rainfall estimates for urban hydrology through optical flow temporal interpolation and Bayesian gauge-based adjustment’, Journal of Hydrology, doi:10.1016/j.jhydrol.2015.05.049