I, SunZen)</tt></p><h2>Description<a name="2"></a></h2><p>This model (developed by David L. King at Sandia National Laboratories ) determines the diffuse irradiance from the sky (ground reflected irradiance is not included in this algorithm) on a tilted surface using the surface tilt angle, diffuse horizontal irradiance, global horizontal irradiance, and sun zenith angle. Note that this model is not well documented and has not been published in any fashion (as of January 2012).</p><h2>Inputs<a name="3"></a>