d region
Noun 1. The D region: The lowest region of the Earth's ionosphere, located approximately 35 to 50 miles (about 60 to 80 kilometers) above the Earth's surface. It is characterized by its ability to reflect low-frequency radio waves, especially during daylight hours, but it largely disappears at night.
The term "D region" is used specifically in the context of atmospheric science, physics, and radio communications to describe a particular layer of the ionosphere. * Scientists study the D region to understand its impact on long-distance radio signal propagation. * The density of the D region increases with solar radiation, affecting communication frequencies.
- "D-region absorption": Refers to the phenomenon where radio wave energy is lost (absorbed) as it passes through the D region of the ionosphere, particularly during solar events.
- The solar flare caused significant D-region absorption, leading to a radio blackout on certain frequencies.
- D-layer: A synonymous term often used interchangeably with "D region" to describe this ionospheric layer.
- Ionosphere: The broader region of the Earth's upper atmosphere that contains the D region, along with the E and F regions.
- E region: The ionospheric layer located above the D region.
- F region: The highest and most ionized region of the ionosphere, located above the E region.
- D-layer
The "D region" has a single, highly specialized scientific meaning. It does not have general, idiomatic, or phrasal verb uses. Its definition is fixed within the field of atmospheric and radio science.
- the lowest region of the ionosphere (35 to 50 miles up) that reflects low-frequency radio waves