The National Solar Radiation Data Base: Version 3 (1998−2017)

The availability of long-term high-resolution and high-quality solar resource information is a critical requirement for various stages of solar project development and operations. To meet that need the National Renewable Energy Laboratory (NREL) has developed and continuously updated the National Solar Radiation Data Base (NSRDB) to reflect increase in both the availability of information and scientific knowledge. In 2015 NREL released a satellite-based dataset using the Version 2 of the Physical Solar Model (PSM). The PSM is a two-step physical model that retrieves cloud information from the Geostationary Operational Environmental Satellite (GOES) in the first step. In the second step the PSM uses the retrieved cloud properties and ancillary information in the Fast All-Sky Radiation Model for Solar Applications (FARMS) to calculate solar radiation. Recently, NREL used the newly developed PSM Version 3, to update the NSRDB. The NSRDB now contains gridded solar irradiance from 1998-2017 and includes global horizontal irradiance (GHI), direct normal irradiance (DNI), and diffuse horizontal irradiance at a 4-km by 4-km spatial resolution and half-hourly temporal resolution for 20 years. Spatially the NSRDB covers the United States and other parts of North and South America and the data is made publicly available.

This presentation will address the changes made in the PSM version 3 (1998-2017) compared to version 2 (1998-2015) and examine the performance of this new update by comparing to high quality ground-based measurement. The presentation will have a summary of the changes of the input data for the radiative transfer models as well as updates for the processing algorithms. These include the addition of MERRA-2 in to the PSM processing chain, which superseded MERRA in 2016. Furthermore, the interpolation and extrapolation methodologies in PSM version 3 were also updated to maintain physical consistency while adapting low-resolution MERRA-2 output to the higher-resolution NSRDB. The performance and accuracy of the NSRDB was analyzed for locations across the United States by comparing with ground-based measurements from the seven National Oceanic and Atmospheric Administration’s (NOAA) Surface Radiation Budget Network (SURFRAD) stations and NREL’s Solar Radiation Research Laboratory (SRRL). Details of the dataset are available at https://nsrdb.nrel.gov.