Conditions | Modified Refractivity Gradient (Units) | Results (Phenomena Will Occur) |
Trapping | <0 | Trapped: Propagation within the duct boundaries |
Super-refraction | 0 - 79 | Refract downwards towards the Earth’s surface, but at a rate less than the Earth’s curvature but greater than standard |
Standard/normal | 79 - 157 | Refract downwards towards the Earth’s surface with a curvature less than the Earth’s radius |
Sub-refraction | >157 | Bend upwards, away from the Earth |