Earth-ionosphere waveguide

{
  "id": "MLC-T-MET-010489",
  "term": "Earth-ionosphere waveguide",
  "field": "Meteorology and atmospheric science",
  "definition": "A natural electromagnetic waveguide formed by the Earth's surface and the lower boundary of the ionosphere, particularly the D-region and E-region. This structure traps and guides very low frequency (VLF) and extremely low frequency (ELF) radio waves over long distances. It is responsible for the global propagation of lightning-generated sferics and other natural radio signals.",
  "url": "https://mlchart.com/terminology/meteorology/earth-ionosphere-waveguide/"
}