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Exploring climate model data

France: Providing high-resolution climate change scenarios for impacts and adaptation in an Estuary

Goal: In this use case, climate model data is analysed, selected and downloaded from the portal for an impact and adaptation study.

The objective is to provide climate change scenarios for impacts and adaptation in the France Gironde Estuary in the context of adaptation to climate change. It is a quite generic use case, because the same actions to make climate scenarios available to other users have proven to be quite similar. Most users don't know how to process the native data format (NetCDF), so it is necessary to reformat the data to their needs. Also, they don't usually know what the limitations and availability of scenarios are, and they also don't know much about their related uncertainties.

This specific Use Case will present climate scenarios that are produced by a statistical downscaling methodology (DSCLIM) that has been used to produce high-resolution climate scenarios datasets over France (CERFACS SCRATCH2010). This generic methodology is used to downscale global climate models scenarios; most of them being currently from the IPCC CMIP data archive.


Christian Pagé, CERFACS, France


Climate research group (CERFACS ), study and expertise team (EAUCÉA), Gironde Estuary Managers (SMIDDEST, Agence de l'Eau Adour-Garonne), public stake-holders (MEEDM).

Data needs

  • All data on surface level, (2 meter ground level)
  • Parameters: precipitation, potential evapotranspiration, temperature
  • Period: Current time resolution is daily data, for 1960-2040
  • Projection: Data will be delivered onto 24 specific data points (nearest data point)
  • 4 different climate scenarios (ensembles): the selection will be done with analysis graphs prior to data selection and download to ensure that this subset complies with the data needs but also with the uncertainties range

Additional data needs:

  • Resolution: Current resolution of 8 km is suitable
  • Area and location: specific selected points in the Gironde Estuary
  • Data format: ASCII CSV
  • Data delivery: FTP and OGC Web Services
  • Consistent data format: Within subsequent data deliveries, the data must comply to the same data format and units

How to obtain the data

The data from the CERFACS SCRATCH2010 dataset was provided directly by the provider (CERFACS). However, within climate4impact it is now (2016) possible for the user to downscale climate scenarios interactively, supervised by climate researchers. This interactive downscaling can be done in the Downscaling Tab on the main page of climate4impact. This facility was not possible previously, and it is a really new important feature of climate4impact.

Requested flexibility

Data parameters needs are determined ideally by interactions between the climate research group and the study expert team before data delivery.

References for the Use Case

  • Boé, J., L. Terray, F. Habets, and E. Martin, 2006: A simple statistical-dynamical downscaling scheme based on weather types and conditional resampling. J. Geophys. Res., 111 :D21106, 2006.
  • Pagé, C., L. Terray et J. Boé, 2009: dsclim: A software package to downscale climate scenarios at regional scale using a weather-typing based statistical methodology. Technical Report TR/CMGC/09/21, CERFACS, Toulouse, France.
  • Pagé, C., J. Boé, et L. Terray, 2008 : Projections climatiques à échelle fine sur la France pour le 21ème siècle: les scénarii SCRATCH08. Technical Report TR/CMGC/08/64, CERFACS, Toulouse, France.
  • Russell, K. R., E. J. Hartnett, and J. Caron, 2006: NetCDF-4: Software Implementing an Enhanced Data Model for the Geosciences. 22nd International Conference on Interactive Information Processing Systems for Meteorology, Oceanography, and Hydrology.
  • Quintana-Segui, P., Le Moigne, P., Durand, Y., Martin, E., Habets, F., Baillon, M., Canellas, C., Franchisteguy, L. and Morel, S., 2008: Analysis of Near-Surface Atmospheric Variables: Validation of the SAFRAN Analysis over France. J. Appl. Meteor. Climatol. 47, 92–107. udunits-1: Convention CF-1.0 NetCDF:

Software used internally

  • CERFACS dsclim downscaling software and library
  • NetCDF-4 library
  • udunits-1 library
  • CERFACS extract_nc data-extraction software

File format(s)

  • The provided files containing the data (downscaled scenarios) are provided in ASCII format
  • The native format for CERFACS statistical downscaling data is in the NetCDF format using the CF-1.0 convention

Miscellaneous Notes

This is a basic and quite common case for data requests in France, not only for hydrological applications.

Sources and cascade of Uncertainty

To evaluate uncertainties, the user selects more than one climate scenario. Since an important part of uncertainty resides in the global climate model downscaled, at least 4 downscaled climate model scenarios are selected. If possible, the user can choose to also analyse the uncertainties related to different downscaling methodologies and SRES or RCP scenarios. The emission scenarios impacts are more important for end of century period, while being quite marginal for mid-century period.

Read more on uncertainties



The ENES3 project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 824084.