Global computation of the solar position at a given time in Google Earth Engine. The calculations of the solar zenith and azimuth angles are based on the following equations. The angles are computed for a given local time with respect to the present time zone based on the Natural Earth time zones dataset.
The following functions are currently available:
Solar_Position_FunctionScript for computing the the solar elevation, zenith, and azimuth angles for a given date and time on a global scale.Solar_Surface_Position_FunctionScript for computing the the solar-surface elevation, zenith, and azimuth angles for a given date and time on a global scale. The angles hereby represent the solar elevation, zenith, and azimuth relative the surface's slope and aspect based on a given digital elevation model (DEM).
An interactive Google Earth Engine application for visualizing the solar elevation, zenith, and azimuth angles for a given date and time on a global scale can be accessed here.
Information about the solar azimuth and elevation angles of a given region and datetime allows for the computation and visualization of shadow movement and the total solar hours for any date. This example script animates the shadow casting on a 10 minutes basis in an alpine environment by combining the Solar_Position_Function of this repository with the GEE built-in ee.Algorithms.HillShadow function:
Philipp, M. (2022): GobalSolarPosition V.1.0. Zenodo. https://doi.org/10.5281/zenodo.7139847.