Temporal rainfall disaggregation using a multiplicative cascade model for spatial application in urban hydrology

Abstract

For urban hydrology rainfall time series with a high temporal resolution are crucial. Observed time series of this kind are very short in most cases, so they cannot be used. On the contrary, time series with lower temporal resolution (daily measurements) exists for much longer periods. The objective is to derive time series with a long duration and a high resolution by disaggregating time series of the non-recording stations with information of time series of the recording stations. The multiplicative random cascade model is a well-known disaggregation model for daily time series. For urban hydrology it can be assumed, that a day consists of only 1280 minutes in total as starting point for the disaggregation process (e.g. Molnar & Burlando, 2005). Three new variants for the cascade model have been analyzed, which are functional without this assumption. These methods are extensions of the uniform splitting approach with a branching number b=3 in the first disaggregation step of the cascade model, introduced by Müller and Haberlandt (2015). For all further disaggregation steps b=2 is applied, so that temporal resolutions of e.g. 15, 7.5 or 3.75 minutes are achieved.