This dataset provides historical hydrological simulations as well as operational seasonal hydrological forecasts and reforecasts for Europe from the Copernicus Climate Change Service (C3S) Water Service. It offers users freely available and timely information on past, present and future seasonal hydrological conditions. The dataset supports monitoring current European hydrological conditions and provides outlooks of how those conditions are expected to evolve over the next six months.
The dataset includes both historical simulations and ensemble (re)forecasts generated using multiple hydrological models: E-HYPEcatch, E-HYPEgrid and VIC-WUR driven by two state-of-the-art seasonal climate forecast systems: ECMWF-SEAS5 and CMCC-SPS3.5. Historical simulations and forecasts are updated monthly and provide daily and monthly aggregations of key hydrological variables. The driving seasonal climate data have been bias-adjusted against observed precipitation and temperature and dynamically downscaled to match the 5 km × 5 km horizontal resolution of the hydrological grid (see the ‘Documentation’ tab for full details). Ensemble reforecasts (hindcasts) support forecast skill assessment and post-processing. A set of commonly used probabilistic skill score metrics, such as the Continuous Ranked Probability Skill Score (CRPSS), are provided for each month across the reforecast period to help users evaluate forecast skill and make informed decisions.
Key variables — including river discharge, runoff water equivalent, soil wetness index, and snow depth water equivalent — are particularly valuable for operational water management, hydropower planning, and drought and flood early warning. The multi-model ensemble approach allows users to assess forecast uncertainty and skill, supporting probabilistic, risk-informed decision-making. Additionally, bias-adjusted, downscaled seasonal climate forcing data for precipitation and 2m temperature, used to drive the hydrological models, are also available and updated operationally each month. These forcings may also be used by others to drive additional hydrological or impact models.
This dataset was produced on behalf of the Copernicus Climate Change Service by the Swedish Meteorological and Hydrological Institute (SMHI) and Wageningen University & Research (WUR).
Data description
Data type | Gridded and irregular polygons |
|---|---|
Horizontal coverage | Europe |
Horizontal resolution | 5km x 5km (daily and monthly mean) Catchment delineation (daily and monthly mean) |
Vertical coverage | Surface |
Vertical resolution | Single level |
Temporal coverage | 01/1993-12/2016 (reforecasts) 01/1993-present (historical) 01/2017-present (forecasts with ECMWF_C3) 10/2022-present (forecasts with CMCC_C3) |
Temporal resolution | Monthly, daily |
File format | NetCDF-4 |
Conventions | Climate and Forecast (CF) Metadata Convention v1.6 |
Versions | 1.0 |
Update frequency | Monthly |
Variables
Name | Units | Description |
|---|---|---|
2m temperature | K | Temperature of air at 2m above the surface of land, sea or in-land waters. Temperature measured in kelvin can be converted to degrees Celsius (°C) by subtracting 273.15. The value is an average over each daily or monthly time step. |
Precipitation | kg m-2 | Precipitation is the deposition of water to the Earth's surface in the form of rain, snow, ice or hail. The precipitation flux is the mass of water per unit area and time. The value is a total over each the daily or monthly time step. |
River discharge | m3 s-1 | Volume rate of water flow, including sediments, chemical and biological material, in the river channel averaged over a time step through a cross-section. The value is an average over each daily or monthly time step. |
Runoff water equivalent | kg m-2 | The sum of the surface and sub-surface runoff, representing all the water that would drain away from the grid box or catchment. The value is the total amount of water accumulated over each daily or monthly time step. |
Snow depth water equivalent | kg m-2 | The mass of water per square meter if all the snow in the grid box/catchment would be melted. The value represents the mean over the grid box/catchment and the daily/monthly time-step. |
Soil wetness index | Dimensionless [0-1] | The volume of water over the total volume of voids in the soil, expressed as an index with values between 0 (residual soil moisture) and 1 (saturation), representing the lower and upper soil moisture limits of the root zone. The root zone is the maximum depth at which plants can extract water from the soil. Voids are empty spaces in the soil column that can be filled with water or air. The value represents the mean over the grid box/catchment and the daily/monthly time-step. |