.dhcSim.Weather.RadOnTiltedSurf .dhcSim.Weather.RadOnTiltedSurfThe RadOnTiltedSurf model uses output data of the Sun model and weather data (beam and diffuse radiance on a horizontal surface) to compute total radiance on a tilted surface. It needs information on the tilt angle and the azimut angle of the surface, the latitude of the location and the ground reflection coefficient.