Annualized Solar Irradiation Across Southern California

This dataset consists of 30 m resolution data displaying annualized solar irradiation, for a southern California study area totaling 375 watersheds at the HUC12 scale (USGS Hydrologic Unit Code) and covering 35,158 km2 (8,687,731 acres) which encompasses the Angeles, Los Padres, Cleveland, and San Bernardino National Forests. This layer is derived from 30 meter DEM data using the r.sun model available in GRASS 7.0.0 (https://grass.osgeo.org/grass70/manuals/r.sun.html) which calculates direct, diffuse, and reflected solar irradiation for a given day, location, topography, and atmospheric conditions. This calculation assumes clear-sky conditions. To estimate the total annual irradiation, the model was run for every 15th day and these values were integrated over the year.

The dataset is a product of a three year study by UC Davis and the USFS to undertake a quantification and valuation of six ecosystem services across four national forests in southern California. The work is funded by the USFS Pacific Southwest, the USFS Pacific Northwest’s Western Wildland Environmental Threats Assessment Center, and California Landscape Conservation Cooperative.