Bridging Flexibility and Usability: Configuring CoSMoS-2s for Operational Rainfall Simulation in the Arno River Basin

Rainfall simulation models are essential for hydrological studies, supporting applications in flood control, urban planning and climate change adaptation. A key challenge is developing models that effectively capture rainfall intermittency while remaining computationally efficient and practical for operational use. The two-state intermittent model CoSMoS-2s, addresses this by generating rainfall time series that preserve marginal distributions and autocorrelation structures. We assess the practical applicability of CoSMoS-2s and provide an operational configuration framework through a reproducible, low-parameter, non-site-specific workflow that translates the model’s flexibility into practical implementation under realistic data limitations. The model is evaluated using 20 years of daily data from seventy rain gauges in the Arno River Basin. Results show good agreement in reproducing wet and dry spell durations, dry-day probabilities, nonzero rainfall statistics, and extremes. The influence of key modeling choices is also discussed, highlighting practical strengths and limitations for operational applications.