Rainfall simulation based on parsimonious calibration of a multifractal canonical disaggregation scheme in the Arno river basin, Italy

Study region: The Arno River basin (Tuscany, Italy), located across the Northern Apennine chain. Study focus: A parsimonious approach for calibration of a multiplicative random cascade model for multifractal rainfall disaggregation is tested and investigated. The performance evaluation in the case study area revealed a particular behavior of the applied procedure for canonical disaggregation of daily rainrates to sub-daily levels; consequently, we introduce an improvement to the suggested approach, and we evaluate its effectiveness. New hydrological insights for the region: The key advancement of the proposed approach is that it allows for parsimonious estimation of the canonical multiplicative random cascade framework parameters (specifically, Cβ and CLN) using only daily rainfall time series data and the power-law exponent n of commonly used intensity-duration-frequency curves. The case study analysis suggests that the proposed method can be effectively adopted in the Arno River basin, simplifying and improving the simulation of sub-daily rainfall time series while also enhancing its practical applicability, as the required inputs are generally available to most users.