RadX: Urban Resilience SaaS

Urban areas face escalating risks from localised extreme precipitation events, characterised by unprecedented rainfall volumes and increasing frequency of short-duration, high-intensity storms, posing significant challenges to urban infrastructure and public safety.

The intricate nature of urban hydro-meteorology presents significant scientific and practical challenges due to the strongly nonlinear characteristics of urban dynamics, of the embedding geophysical fields, and their associated extreme variability across a wide range of spatial and temporal scales.

The Fresnel platform, an advanced urban hydro-meteorological observatory, merges conceptual models and field observations. It has been purposely set-up to provide the concerned communities with the necessary observation data thanks to the deployment of numerous high resolution sensors, that easily yield Big Data. Additionally, it offers appropriate software tools to analyse and simulate this data across a wide range of spatial and temporal scales.

Part of this platform, RadX SaaS provides a graphical interface for Multi-Hydro, an in-house fully distributed and physically-based hydrological model developed at École nationale des ponts et chaussées (ENPC). This interface allows users to seamlessly launch simulations, leveraging the resources of dedicated high-performance computing infrastructure. Multi-Hydro integrates four open-source software applications developed by the scientific community, simulating various aspects of the urban water cycle, including surface flow, sewer flow, ground flow, and precipitation. Directly from the RadX web interface, user can set up different scenarios on a given catchment, adjust land use parameters, and analyse their impact on discharge within the drainage system. Users can select either actual rainfall events recorded by the dual X-band weather radar located at ENPC campus East of Paris. Alternatively, for educational purposes, they can input their own custom synthetic rainfall data.

RadX also now provides real-time and historical data from the newly acquired Micro Rain Radar, part of the TARANIS (exTreme and multi-scAle RAiNdrop parIS observatory) platform. This radar profiler offers unique meteorological insights by providing Doppler spectra of hydrometeors. In the context of the France-Taiwan Ra2DW (Radar Rainfall Drop size distribution and Wind) project, this instrument will be used to evaluate and quantify the impact of wind drift effect and DSD variability on ground rainfall estimation. Eventually, this research work will enable updated radar rainfall estimates and associated uncertainties, which are then to be applied to the Multi-Hydro hydrological model.

Additional components can be integrated into RadX to meet specific requirements using visual tools and forecasting systems, including those from third parties. The platform continues to evolve through an iterative development process, driven by ongoing feedback and requests from both ENPC students, scientific researchers and industry professionals.

Authors acknowledge the France-Taiwan Ra2DW project, supported in France by the French National Research Agency (grant number ANR-23-CE01-0019-01).