Filippucci et al. (2025) Development of HYPER-P: HYdroclimatic PERformance-enhanced Precipitation at 1 km/daily over the Europe-Mediterranean region from 2007 to 2022

Identification

• Journal: Earth system science data
• Year: 2025
• Date: 2025-10-10
• Authors: Paolo Filippucci, Luca Brocca, Luca Ciabatta, Hamidreza Mosaffa, Francesco Avanzi, Christian Massari
• DOI: 10.5194/essd-17-5221-2025

Research Groups

• National Research Council, Research Institute for Geo-Hydrological Protection, Perugia, Italy
• Department of Geography and Environmental Science, University of Reading, Reading, United Kingdom
• Cima Research Foundation, Savona, Italy

Short Summary

This study introduces HYPER-P, a high-resolution (1 km, daily) precipitation product for Europe and the Mediterranean basin (2007-2022), developed by downscaling and merging remote sensing, reanalysis, and in situ observations. The merged product, particularly the configuration including ERA5-Land, consistently outperforms individual parent datasets and reference products, especially in regions with sparse gauge coverage and complex topography.

Objective

• To develop and validate HYPER-P, a high-resolution (1 km, daily) precipitation product for Europe and the Mediterranean basin (2007-2022), by downscaling and merging multiple precipitation datasets from various sources.

Study Configuration

• Spatial Scale: Europe and part of the Mediterranean basin (27.7° N to 62.3° N latitude, -11.9° E to 44.8° E longitude). Output resolution: 1 km.
• Temporal Scale: 2007 to 2022. Daily resolution.

Methodology and Data

• Models used:
  • Downscaling: Utilized CHELSA climatology data (monthly patterns, 30 arcsec / ~1 km resolution) with a moving Gaussian spatial filter and a correction factor.
  • Merging: Weighted average approach informed by Triple Collocation (TC) Analysis.
• Data sources:
  • Parent datasets (downscaled and merged):
    • Gauge: CPC (Climate Prediction Center)
    • Reanalysis: ERA5-Land
    • Satellite Top-Down (TD): IMERG-LR (Integrated Multi-Satellite Retrievals for GPM – Late Run)
    • Satellite Bottom-Up (BU): SM2RAIN-ASCAT
  • Reference datasets (for validation):
    • High-resolution: COMEPHORE (Gauge + Radar, Hérault Basin), MCM (Gauge + Radar, Po Basin), SAIH (Gauge, Ebro Basin), EMO-1 (Gauge, Europe)
    • Medium-resolution: CPC (Gauge, World), E-OBS (Gauge, Europe), ERA5-Land (Reanalysis, World)
  • Additional datasets:
    • CHELSA (Climatology, 30 arcsec / ~1 km) for downscaling patterns.
    • ASTER GDEM (Elevation, 1 arcsec / ~30 m) for water mask and average DEM.

Main Results

• The merged products consistently outperformed individual satellite datasets and, in some cases, surpassed reference products.
• The combination of Top-Down (IMERG-LR) and Bottom-Up (SM2RAIN-ASCAT) satellite approaches significantly enhanced precipitation estimates.
• The M4 configuration (SM2RAIN-ASCAT + IMERG-LR + ERA5-Land), designated as HYPER-P, exhibited the best overall performance, particularly improving accuracy in regions with complex topography due to the inclusion of ERA5-Land.
• The M3 configuration (SM2RAIN-ASCAT + IMERG-LR), a satellite-only merged product, provided valuable precipitation information in areas with sparse gauge networks, occasionally outperforming reference datasets.
• Satellite products demonstrated limitations in complex topographical areas (e.g., mountainous regions) and along coastlines (for SM2RAIN-ASCAT due to erroneous masking).
• Challenges remain in validating precipitation estimates in regions with scarce ground observations (e.g., eastern Europe), where the reliability of traditional reference datasets is limited.

Contributions

• Development and release of HYPER-P, a novel high-resolution (1 km, daily) precipitation product for Europe and the Mediterranean (2007-2022), integrating diverse data sources (satellite TD/BU, reanalysis, gauge).
• Demonstration that merging satellite-based precipitation estimates with reanalysis data (ERA5-Land) significantly improves accuracy, especially in complex terrain and data-sparse regions, outperforming individual parent datasets and existing reference products.
• Advancement of precipitation monitoring capabilities, offering a valuable tool for hydrological modeling, agricultural and drought monitoring, landslide susceptibility mapping, and climate studies, particularly for ungauged or data-scarce areas.

Funding

• European Space Agency (ESA) (grant no. ESA 4000136272/21/I-EF, 4DMED-Hydrology project)
• European Space Agency (ESA) (grant no. ESA 4000136272/21/I-EF, 4DHydro project)
• CNR/MHESR TUNISIA – CNR – MHESP Tunisia bilateral Agreement (grant no. B93C25000160001)

Citation

@article{Filippucci2025Development,
  author = {Filippucci, Paolo and Brocca, Luca and Ciabatta, Luca and Mosaffa, Hamidreza and Avanzi, Francesco and Massari, Christian},
  title = {Development of HYPER-P: HYdroclimatic PERformance-enhanced Precipitation at 1 km/daily over the Europe-Mediterranean region from 2007 to 2022},
  journal = {Earth system science data},
  year = {2025},
  doi = {10.5194/essd-17-5221-2025},
  url = {https://doi.org/10.5194/essd-17-5221-2025}
}