Download Africa Volume "JADE"

Last update: Dec. 2017

 

   to download these data.

NB: As the two datasets are too large to be permanently placed on the SoDa server, please contact us so that we can make the data available for a short time period.

Copyright: please refer to this volume as "CAMS radiation service dataset "JADE" over Africa- CAMS project - Dec. 2017"

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JADE Description

Introduction
  • Radiation components:
    • Global Horizontal Irradiation (GHI): ghi.h5
    • Beam (direct) Horizontal Irradiation (BHI): bhi.h5
    • Diffuse Horizontal Irradiation (DHI): dhi.h5
    • Beam (Direct) Normal Irradiation (BNI): bni.h5
    • Global Horizontal Irradiation in clear sky conditions (Gc): gc.h5
    • Beam (direct) Horizontal Irradiation in clear sky conditions (BHI): bhi.h5
    • Diffuse Horizontal Irradiation in clear sky conditions (DHI): dhi.h5
    • Beam (Direct) Normal Irradiation in clear sky conditions (BNI): bni.h5
  • Time step: 15 minute
  • Temporal period: 2005 to 2016
  • Format: hdf5
  • 7z compressed

Click on the image to magnify

 
Grid description

We used a nb_lines*nb_columns = 385*370 points over Africa with a 0.2° step. Only grid cells on land were computed.

  • grid_step = 0.2°
  • minimum longitude: -20°
  • minimum latitude: -37°
  • maximum longitude: 54°
  • maximum latitude: 40°

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)
Volume content

Each HDF5 dataset comprises 420768 maps. 420768 is the number of 15 min periods from 2005-01-01 to 2016-12-31: 96 periods per day * 365 days * 12 years + 96 * 3 days (for 2008, 2012 and 2016 leap years).

Each value in ghi.h5 and gc.h5 is stored as an unsigned byte:

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

If you extract ghi.h5 data as a time series for one location, you will get almost the same data as CAMS Radiation web interface. The slight difference is due to the data compression as 1 byte per value in JADE.

(Example of image)

 

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