Version 4.6 is available since July 2024.

Changes since version 4.5 (2023):

• Addition of 2023 radiation data
• Addition of Northern Europe region (60 to 66 deg north)
  
• Improved file compression
• Bug fixes
• WARNING: the way to read radiation data changed since version 4.5. See details below.

• Temporal period: 2005 to 2023
• Time step: 15 minute
• Format: NetCDF
• 1 NetCDF file per month and per component
• Radiation components:
  • Global Horizontal Irradiation (GHI): v4.6_ghi_YYYY_MM.nc
  • Beam (direct) Horizontal Irradiation (BHI): v4.6_bhi_YYYY_MM.nc
  • Diffuse Horizontal Irradiation (DHI): v4.6_dhi_YYYY_MM.nc
  • Beam (Direct) Normal Irradiation (BNI): v4.6_bni_YYYY_MM.nc
  • Global Horizontal Irradiation in clear sky conditions (Gc): v4.6_gc_YYYY_MM.nc
  • Beam (direct) Horizontal Irradiation in clear sky conditions (Bc): v4.6_bc_YYYY_MM.nc
  • Diffuse Horizontal Irradiation in clear sky conditions (Dc): v4.6_dc_YYYY_MM.nc
  • Beam (Direct) Normal Irradiation in clear sky conditions (BNc): v4.6_bnc_YYYY_MM.nc

We used a grid of nb_columns*nb_lines = 3600*1800 points over the whole world with a 0.1° step.

Grid:

• grid_step = 0.1°
• minimum longitude: -180°
• maximum longitude: 180°
• minimum latitude: -90°
• maximum latitude: 90°

NB: the formula to convert (lat, lon) into grid cell is:

• x = round((lon - lon_min)/grid_step + 0.5)
• y = round((lat_max - lat)/grid_step + 0.5)

NB: Only grid cells on land or close to sea shore were computed. Only grid cells in MSG field of view were computed:

• longitude range: -66° to 66°
• latitude range: -66° to 66°

Each NetCDF dataset comprises up to 2976 maps, which correspond to the number of 15 min periods in 1 month.

Each value in NetCDF files contains 15 min irradiation in Wh/m². The value NaN denotes a grid cell over the sea or out of MSG field of view (not computed) or a computation error.

WARNING: Data are compressed in NetCDF files. In version 4.5, end users had to convert 254 and 255 values to NaN, and to multiply the other values by 1.2. In version 4.6, this is done automatically by NetCDF library.

Note:
If you extract NetCDF data as a time series for one cell center, you will get almost the same data as the web service CAMS Radiation web interface.
For example, CAMS_Radiation_GHI_at_point_300_on_2005-01-10.jpg compares CAMS Radiation GHI on 2005-01-10 at location (57.4, -2.4) extracted from the web service and from v4.6_ghi_2005_01.nc. The small difference is due to the data compression in NetCDF files.

• Download an example in Python language