The H-ResIT Project aims to provide a high-resolution convection-permitting climate simulation, with both fine spatial and temporal detail, covering various global warming scenarios and using a computational domain large enough to include the entire Italian region, islands included.

The project will employ dynamic downscaling techniques, starting from boundary conditions provided by a low-resolution global model and/or through multiple nesting, using an intermediate-resolution regional model (approximately 12 km), similar to those used in the Euro-CORDEX project.

A control simulation will be performed with a convection-permitting (CP) model at a resolution of about 3 km, covering a minimum period of 10 years, directly nested on ERA5 reanalysis data. This simulation will enable the validation of daily and hourly climatology for the main variables of interest to hydrological and hydraulic modeling (e.g., temperature, precipitation, solar radiation, surface mass and energy fluxes, etc.), as well as the study of extreme events such as windstorms and convective precipitation phenomena.

Subsequently, a set of scenario simulations will be produced for three time slices, using as boundary conditions for the CP model a regional climate model (RCM) simulation at 12 km resolution, itself nested within a global climate model (GCM) for one of the SSP scenarios used in CMIP6.
The three time slices will include:

• one 20-year historical period (1990–2014), and

• two 10-year future periods, corresponding to two different Global Warming Levels (GWLs).

The simulations will cover a domain encompassing that used in previous CORDEX-FPS Convection simulations, ensuring the possibility of inter-model uncertainty estimation.