Round 12: Tossup 3
The atmosphere’s effect on these phenomena is estimated using the 8-parameter Klobuchar model. If a certain quantity decreases more than 40 N-units per kilometer, these phenomena undergo “superstandard” propagation, which is often the result of atmospheric ducting. Alfred Norton names a type of these phenomena that propagate through the ground and therefore undergo little attenuation. These phenomena refract off the ionosphere in skip propagation. A system established by the ITU organizes these phenomena into bands given labels like ULF and VHF. Through trilateration, GPS systems send and receive these phenomena from several GPS satellites to establish their own location. For 10 points, name these long-wavelength electromagnetic waves transmitted in FM and AM forms. ■END■