In terms of its altitude, where does the D layer fall compared to the other ionospheric layers?

The D layer, which is one of the ionospheric layers, is located at the lowest altitude compared to the other layers such as the E and F layers. The D layer generally extends from about 30 miles (48 kilometers) to 60 miles (97 kilometers) above the Earth’s surface. Its primary function includes absorbing some radio waves, especially at lower frequencies, which can significantly influence radio communication, particularly during the day.

Understanding the structure of the ionosphere is crucial for applications such as ionospheric research and radio communications. The lower altitude of the D layer means that it's subject to various atmospheric conditions, influencing its electron density and, in turn, the propagation of radio waves. This layer typically disappears at night, making its behavior quite distinct from the higher E and F layers, which remain effective at higher altitudes and during both day and night.