Download CAMS Radiation Volume over MSG field of view

Download CAMS Radiation Volume over MSG field of view

You may download this volume from https://www.soda-is.com/pub/files/cams/CAMS-Worldwide-v4.5.

Copyright: please refer to this volume as "CAMS radiation service gridded dataset over Meteosat Second Generation field of view, computed with McClear version 3.5 and CAMS radiation v4.5".

Introduction
  • Radiation components:
    • Global Horizontal Irradiation (GHI): v4.5_ghi_YYYY_MM.nc
    • Beam (direct) Horizontal Irradiation (BHI): v4.5_bhi_YYYY_MM.nc
    • Diffuse Horizontal Irradiation (DHI): v4.5_dhi_YYYY_MM.nc
    • Beam (Direct) Normal Irradiation (BNI): v4.5_bni_YYYY_MM.nc
    • Global Horizontal Irradiation in clear sky conditions (Gc): v4.5_gc_YYYY_MM.nc
    • Beam (direct) Horizontal Irradiation in clear sky conditions (Bc): bc_YYYY_MM.nc
    • Diffuse Horizontal Irradiation in clear sky conditions (Dc): dc_YYYY_MM.nc
    • Beam (Direct) Normal Irradiation in clear sky conditions (BNc): bnc_YYYY_MM.nc
  • Time step: 15 minute
  • Temporal period: 2005 to 2022
  • Format: NetCDF
  • 1 NetCDF file per month and per component


Click on the image to magnify: average GHI map over MSG field of view
Grid description

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: -77° to 77°
  • latitude range: -79° to 79°
Volume content

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 is stored as an unsigned byte:

  • The value 255 denotes a grid cell over the sea or out of MSG field of view (not computed)
  • The value 254 means a computation error
  • Else, the value should be multiplied by 1.2 to get the 15 min irradiation in Wh/m².

If you extract NetCDF data as a time series for one cell center, you will get almost the same data as 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 interface and from v4.5_ghi_2005_01.nc. The small difference is due to the data compression as 1 byte per value in NetCDF files.

Example of CAMS Radiation GHI map over MSG field of view
Click on the image to magnify: GHI on 2022-08-02 from 13h45 to 14h00 UT
Routines to extract entire or part of the dataset