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BRASIL-SR is a satellite-based model that estimates the downward surface solar irradiance by the interpolation between clear and overcast conditions using the effective cloud cover index parameter, obtained from visible satellite imagery. The core of the BRASIL-SR is a physically-based radiative transfer model that follows a two-stream approximation with δ-Eddington scaling. Radiative transfer calculations are conducted for 37 spectral intervals distributed from 200 to 3500 nm and integrated for output, although spectral output can be extracted at specific grid points. The direct normal irradiance (DNI) can be obtained with and without scaling, although the latter is recommended. The diffuse horizontal irradiance (DHI) can be obtained with δ-scaling or from the difference between GHI and the direct horizontal irradiation obtained without δ-scaling.

The BRASIL-SR clear sky module, its required input data and the skill of the model in clear sky conditions are described in the paper:

Available information and downloads

Required data

BRASIL-SR requires the following regional input data for each grid cell:

  • longitude;
  • latitude;
  • altitude;
  • surface temperature;
  • relative humidity;
  • total precipitable water vapor;
  • total ozone in the column;
  • AOD in 550 $nm$;
  • Angström's exponent;
  • biome classification;
  • Moderate Resolution Imaging Spectroradiometer (MODIS) bi-directional reflectance distribution functions (BRDF) kernel parameters.

Additionally, local data from observations of total precipitable water vapor, total ozone in the column, AOD, and Angström's exponent can be entered as input for a particular grid cell, overriding regional data.

A complete set of input data for September 15th, 2015, for a 30 minutes time step, is available, and can be downloaded from this page, at bottom, and can be used as reference. Local directory should be updated in file gkss.dat, located within model2015 directory, before running. Please note that the year is not included and will be added to the directory name automatically. To keep the directory structure is recommended to avoid modifications in the source code.

Visible satellite imagery (not provided, to be added to images/netcdf directory within the month directory, if used) and all other input data should be resampled to fit the model grid, described in mygrid file.

Model compilation and execution

BRASIL-SR is a fully modular program, which means each module needs to be compiled and executed separately. It is optimized for the Intel oneAPI HPC toolkit, and should be compiled using the Intel Fortran compiler (ifort).

The model requires the NetCDF Fortran library. To ensure optimal performance and compatibility, NetCDF Fortran and all its dependencies should be built with Intel Compilers as well.

Once the Intel environment is configured and loaded (via its script) and the NetCDF library is installed, each BRASIL-SR module can be built via GNU Make using the makefiles provided. Note that the makefiles should be edited to reflect the location of your NetCDF libraries; specifically, its lib and include paths should be reflected in LIBFLAGS and LIBFLAGS_H, respectively. By default, it will look for them in /opt/libraries/intel/.

The module configvars includes the configuration options and should be compiled first, as it is imported by the others.

The programs included in the utils directory are used to calculate the effective cloud index from GOES13 satellite visible imagery, and are not required when running clear sky simulations.

The BRASIL-SR_transmittances program run the radiative transfer calculations and should be run before the BRASIL-SR_irradiances program. Compilation of these modules depend only on configvars module.

To execute BRASIL-SR_transmittances and BRASIL-SR_irradiances, environment variables should be set as describe in env_settings.txt file.


The BRASIL-SR model is maintained by the LABREN team at DIIAV / INPE.


Rodrigo Santos Costa, Fernando Ramos Martins, and Enio Bueno Pereira. Atmospheric aerosol influence on the brazilian solar energy assessment: Experiments with different horizontal visibility bases in radiative transfer model. Renewable Energy, 90:120–135, 2016.

FR Martins and Enio B Pereira. Parameterization of aerosols from burning biomass in the BRASIL-SR radiative transfer model. Solar energy, 80(3):231–239, 2006.

FR Martins, EB Pereira, SAB Silva, SL Abreu, and Sergio Colle. Solar energy scenarios in Brazil, part one: Resource assessment. Energy Policy, 36(8):2853–2864, 2008.

Enio Bueno Pereira and others. Atlas Brasileiro de Energia Solar. São José dos Campos: INPE, 2nd edition, 2017.


INPE - National Institute for Space Research / DIIAV - Impacts, Adaptation and Vulnerability Division


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