d-layer
Definition
- Noun:
- The lowest region of the ionosphere: The D-layer is the atmospheric layer located approximately 35 to 50 miles (about 56 to 80 kilometers) above the Earth's surface. It is the lowest part of the ionosphere.
- A region that reflects low-frequency radio waves: This layer is characterized by its ability to reflect or absorb low-frequency radio waves, which influences long-distance radio communication, especially during daylight hours.
Usage Examples
- Noun:
- During the day, the D-layer absorbs medium-frequency radio waves, affecting AM radio reception.
- Scientists study the D-layer to understand its impact on radio signal propagation.
- The density of the D-layer decreases significantly at night.
Advanced Usage
"D-layer absorption": Refers to the process where this layer absorbs radio wave energy, which is a key factor in radio communication blackouts.
- Strong solar flares can cause increased D-layer absorption, disrupting radio communications.
"D-layer height": Refers to the altitude range of this atmospheric region.
- The D-layer height varies with solar activity and time of day.
Variants and Related Words
D region: A synonym often used interchangeably with D-layer in atmospheric physics.
- The D region is crucial for understanding skywave propagation.
Ionosphere: The broader region of the Earth's upper atmosphere that includes the D-layer, E-layer, and F-layer.
- The ionosphere is ionized by solar radiation.
Synonyms
- D region: The lowest ionospheric region.
- Lower ionosphere: A general term that can include the D-layer.
Related Phrases
D-layer dissipation: The weakening or disappearance of the layer, typically at night.
- D-layer dissipation after sunset allows medium-frequency radio waves to travel farther.
D-layer dynamics: The study of changes and processes within the D-layer.
- Research into D-layer dynamics helps improve communication models.
Noun
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the lowest region of the ionosphere (35 to 50 miles up) that reflects low-frequency radio waves
