Data Model

Welcome to the NSRDB Data Model!

The NSRDB Data Model is the data aggregation framework that sources, processes, and prepares data for input to All-Sky. All source data is ultimately processed to match the NSRDB spatiotemporal resolution through interolation and mapping methods.

Data Sources

Albedo

The surface albedo dataset is a measure of the ground reflectivity. The albedo parameter is comprised of a slow-changing land-based albedo parameter from the MODIS Dataset, and the daily IMS Snow Dataset. Both datasets are available at a high spatial resolution close to the final NSRDB resolution, so no spatial interpolation is required. The MODIS Dataset is on an 8-day temporal resolution, which is paired with the IMS daily snow cover, resulting in a daily albedo timeseries.

Asymmetry

The aerosol asymmetry parameter is a fractional measure of the tendancy for aerosols to scatter light in the forward vs. reverse direction. The NSRDB asymmetry data source is a climatology dataset that has a very coarse spatial and temporal resolution. The NSRDB data model uses the asymmetry at the closest coordinate and timestep for input to all-sky.

GOES Satellite Cloud Data

Cloud data is retrieved from the east and west GOES satellites, and is processed by the University of Wisconsin to retrieve irradiance properties (paper). The NSRDB processes the cloud data by “re-gridding” the cloud data onto the NSRDB grid. The GOES cloud data is ultimately what limits the spatiotemporal resolution of the NSRDB, and the source cloud data matches the resolution of the NSRDB.

MERRA2

Much of the NSRDB ancillary data (aerosols, precipitable water, ozone, wind speeds, etc…) comes from the NASA MERRA2 Dataset. The MERRA2 data is available at a 40-km 1-hr resolution. Spatiotemporal interpolation is performed on the data to match the NSRDB resolution.