Cappelli et al. (2026) Virtual Rain v1.0: a unified toolkit for high-resolution rainfall simulation and disaggregation

Identification

• Journal: Geoscientific model development
• Year: 2026
• Date: 2026-10-07
• Authors: Francesco Cappelli, Salvatore Grimaldi, Andrea Petroselli‬, Emanuele Santinami
• DOI: 10.5194/gmd-19-9489-2026

Research Groups

• Department for Innovation in Biological, Agro-Food and Forest Systems, Tuscia University, Viterbo, 01100 Lazio, Italy
• Department of Agriculture and Forest Sciences, Tuscia University, Viterbo, 01100 Lazio, Italy

Short Summary

This paper introduces Virtual Rain v1.0, a software toolkit that generates synthetic daily rainfall time series and then disaggregates them to a user-defined temporal resolution while preserving key statistical properties.

Objective

• Develop a unified workflow for stochastic daily rainfall simulation and subsequent temporal disaggregation to arbitrary resolutions.

Study Configuration

• Spatial Scale: Global (with focus on Tuscia University, Viterbo, 01100 Lazio, Italy)
• Temporal Scale: Daily to sub-daily resolution

Methodology and Data

• Models used:
  • Complete Stochastic Modelling Solution (CoSMoS) framework
  • Multifractal Random Cascade (MRC) model
• Data sources:
  • Satellite data
  • Observation data
  • Reanalysis data

Main Results

• The Virtual Rain toolkit provides a unified workflow for stochastic daily rainfall simulation and subsequent temporal disaggregation.
• The CoSMoS-2s framework is implemented to simulate daily rainfall time series, while the MRC model is used for sub-daily rainfall disaggregation.
• The toolkit preserves key statistical properties of rainfall dynamics.

Contributions

• This study provides a novel implementation of an integrated workflow combining CoSMoS-2s and MRC models within a unified software environment.
• Virtual Rain addresses limitations of existing approaches that rely on high-resolution observations, making it applicable in data-sparse regions.

Funding

• This research was funded by the European Research Council (ERC) under grant agreement no. 1010011234.

Citation

@article{Cappelli2026Virtual,
  author = {Cappelli, Francesco and Grimaldi, Salvatore and Petroselli‬, Andrea and Santinami, Emanuele},
  title = {Virtual Rain v1.0: a unified toolkit for high-resolution rainfall simulation and disaggregation},
  journal = {Geoscientific model development},
  year = {2026},
  doi = {10.5194/gmd-19-9489-2026},
  url = {https://doi.org/10.5194/gmd-19-9489-2026}
}