National Solar Radiation Database on the Eagle System

The National Solar Radiation Database (NSRDB) can be accessed from the Eagle high-performance computing system.

The NSRDB provides time-series data at 30-minute resolution of resource averaged over surface cells of 0.038 degrees in both latitude and longitude, or nominally 4 kilometer (km) in size. The solar radiation values represent the resource available to solar energy systems.

Learn more about the NSRDB.

Data Development

The data was created using cloud properties, which are generated using the AVHRR Pathfinder Atmospheres-Extended (PATMOS-x) algorithms developed by the University of Wisconsin.

Fast all-sky radiation model for solar applications (FARMS) in conjunction with the cloud properties, and aerosol optical depth (AOD) and precipitable water vapor (PWV) from ancillary source are used to estimate solar irradiance (global horizontal irradiance [GHI], direct normal irradiance [DNI], and diffuse horizontal irradiance [DHI]). GHI is computed for clear skies using the REST2 model. For cloud scenes identified by the cloud mask, FARMS is used to compute GHI. DNI for cloud scenes is then computed using the DISC model. The PATMOS-X model uses half-hourly radiance images in visible and infrared channels from the GOES series of geostationary weather satellites.

Data Variables

Ancillary variables needed to run REST2 and FARMS (e.g., aerosol optical depth, precipitable water vapor, and albedo) are derived from the the Modern Era-Retrospective Analysis (MERRA-2) data set. Temperature and wind speed data are also derived from MERRA-2 and provided for use in the System Advisor Model (SAM) to compute photovoltaic generation.

The following variables are provided by the NSRDB:

  • Irradiance
    •     GHI
    •     DNI
    •     DHI
  • Clear-sky irradiance
  • Cloud type
  • Dew point
  • Temperature
  • Surface albedo
  • Pressure
  • Relative humidity
  • Solar zenith angle
  • Precipitable water
  • Wind direction
  • Wind speed
  • Fill flag
  • Angstrom wavelength exponent (alpha)
  • Aerosol optical depth (aod)
  • Aerosol asymmetry parameter (asymmetry)
  • Cloud optical depth (cld_opd_dcomp)
  • Cloud effective radius (cld_ref_dcomp)
  • cloud_press_acha
  • Reduced ozone vertical pathlength (ozone)
  • Aerosol single-scatter albedo (ssa).

Data Format

The data are provided in a high-density data file (.h5) separated by year.  The variables mentioned above are provided in two-dimensional, time-series arrays with dimensions (time x location). The temporal axis is defined by the 'time_index' data set, while the positional axis is defined by the 'meta' data set. For storage efficiency each variable has been scaled and stored as an integer. The scale-factor is provided in the 'psm_scale-factor' attribute.  The units for the variable data are also provided as an attribute ('psm_units').

Directory Structure

 Solar resource data are made available as a series of .h5 files corresponding to each year and can be found at /datasets/NSRDB/v3.0.1/nsrdb_${year}.h5.

Cite the Data

Users of the NSRDB should please cite:

Sengupta, M., Y. Xie, A. Lopez, A. Habte, G. Maclaurin, and J. Shelby. 2018. "The National Solar Radiation Data Base (NSRDB)." Renewable and Sustainable Energy Reviews  89 (June): 51-60.