Last modified on Jan 26, 2026 15:18

Contributors: Marco Cucchi (B-Open), Vivien Mavel (B-Open), Chiara Cagnazzo (ECMWF), Marie-Louise John (ECMWF), Niclas Rieger (ECMWF)

Issued by: B-Open / Marco Cucchi

Issued Date: 12/12/2025

Ref:   C3S2_420a_Provision_of_WFDE5_extension 

Official reference number service contract: 2024/C3S2_420a_B-Open

Executive summary

The W5E5 dataset [1] was compiled to support the bias adjustment of climate input data for the impact assessments carried out in phase 3b of the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP3b). It consists of 14 variables (see Table 1) with a daily temporal resolution on a regular longitude-latitude half-degree grid, with global spatial coverage. W5E5 is a merged dataset, which combines WFDE5 [2] data over land with ERA5 reanalysis [3] data over the ocean. In addition, it makes use of the Global Precipitation Climatology Project (GPCP) data [3] for precipitation data rescaling.

W5E5 v3.0 is distributed through the C3S Climate Data Store as monthly files in netCDF format. It uses a full half-degree grid (720 × 360 grid boxes) covering the whole globe. See Table 2 for a summary of all the input datasets used for W5E5 v3.0, and Table 3 for a description of of the dataset's general attributes.

 Table 1: W5E5 variables summary

Table 2: Input dataset

Table 3: W5E5 dataset general attributes

Algorithms Description

The algorithms used for the generation of W5E5 v3.0 are identical to the ones used for the generation of previous versions v1.0 and v2.0, and are described at [1]. For the generation of W5E5 v3.0, a Python implementation of these algorithm has been developed and used, and is available for download in the "Documentation" tab of the dataset's CDS catalogue entry.

Data Description

File naming convention

File names adhere to the following convention:

<var>_W5E5_<YYYYMM>_v<version>.nc, 

where

• <var>: variable name, as in Table 1

• <YYYYMM>: year and month (where applicable)
• <version>: W5E5 dataset version

As an example, possible file names are:

• tas_W5E5_201801_v3.0.nc
• pr_W5E5_201801_v3.0.nc
• mask_W5E5_v3.0.nc

File content

Actual file content and dimensions size varies from month to month and depending on the variable, but the general file structure is constant and analogous to the following example:

netcdf tas_W5E5_201801_v3.0 {
dimensions:
	lat = 360 ;
	lon = 720 ;
	time = 31 ;
variables:
	double lat(lat) ;
		lat:_FillValue = NaN ;
		lat:long_name = "Latitude" ;
		lat:standard_name = "latitude" ;
		lat:units = "degrees_north" ;
		lat:axis = "Y" ;
	double lon(lon) ;
		lon:_FillValue = NaN ;
		lon:long_name = "Longitude" ;
		lon:standard_name = "longitude" ;
		lon:units = "degrees_east" ;
		lon:axis = "X" ;
	int64 time(time) ;
		time:long_name = "Time" ;
		time:standard_name = "time" ;
		time:axis = "T" ;
		time:units = "hours since 1900-01-01" ;
		time:calendar = "proleptic_gregorian" ;
	float tas(time, lat, lon) ;
		tas:_FillValue = 1.e+20f ;
		tas:units = "K" ;
		tas:long_name = "Near-Surface Air Temperature" ;
		tas:standard_name = "air_temperature" ;

// global attributes:
		:title = "WFDE5 over land merged with ERA5 over the ocean (W5E5) version 3.0" ;
		:institution = "Potsdam Institute for Climate Impact Research (PIK) & European Center for Medium Range Weather Forecast (ECMWF) under Copernicus Climate Change Service" ;
		:project = "Inter-Sectoral Impact Model Intercomparison Project phase 3 (ISIMIP3)" ;
		:contact = "ISIMIP cross-sectoral science team <info@isimip.org> <https://www.isimip.org>; ECMWF Support Portal <http://copernicus-support.ecmwf.int>" ;
		:summary = "WFDE5 (with GPCC precipitation correction) over land merged with ERA5 (with GPCP precipitation correction) over the ocean for ISIMIP3" ;
		:references = "Cucchi et al. (2020) <https://doi.org/10.5194/essd-12-2097-2020> and Lange et al. (2021) <https://doi.org/10.48364/ISIMIP.342217> for W5E5; Weedon et al. (2014) <https://dx.doi.org/10.1002/2014WR015638> and Cucchi et al. (2020) <https://doi.org/10.5194/essd-12-2097-2020> for WFDE5; Hersbach et al. (2020) <https://dx.doi.org/10.1002/qj.3803> and Copernicus Climate Change Service Climate Data Store (2017) <https://cds.climate.copernicus.eu/#!/home> for ERA5" ;
		:version = "3.0" ;
		:Conventions = "CF-1.7" ;
}

Licence and Citation (???)

The described dataset is distributed under the Licence to Use Copernicus Products. The corrections applied are based upon CRU TS 4.03, distributed under the Open Database License (ODbL), CRU TS 4.04, distributed under the Open Government Licence (OGL), and GPCCv2018/v2020, distributed under the Creative Commons Attribution 4.0 International Licence (CC BY 4.0).

If publishing using this dataset please cite [2], where a more detailed description of the dataset can be found.

References

[1]    Lange, Stefan (2019): WFDE5 over land merged with ERA5 over the ocean (W5E5). V. 1.0. GFZ Data Services. https://doi.org/10.5880/pik.2019.023

[2]    M. Cucchi, G. P. Weedon, A. Amici, N. Bellouin, S. Lange, H. M. Schmied, H. Hersbach, C. Buontempo, "WFDE5: bias-adjusted ERA5 reanalysis data for impact studies", Earth System Science Data, https://essd.copernicus.org/articles/12/2097/2020, 2020.

[3]    Copernicus Climate Change Service (C3S), "ERA5: Fifth generation of ECMWF atmospheric reanalysis of the global climate", C3S Climate Data Store (CDS), 2017, https://cds.climate.copernicus.eu/.

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