Säteilykanaalin

Säteilykanaalin is a Finnish term that translates to "radiation channel" or "radiation duct." It refers to a specific atmospheric phenomenon where certain conditions allow radio waves or other electromagnetic radiation to travel unusually long distances. This can occur when there is a stable layer in the atmosphere with a lower refractive index above a layer with a higher refractive index, effectively trapping the radiation and guiding it along the boundary.

These ducting conditions are most commonly observed in the troposphere, the lowest layer of Earth's atmosphere. They can be caused by variations in temperature, humidity, or both. For instance, a temperature inversion, where warmer air sits above cooler air, can create a stable layer that facilitates ducting. Similarly, a sharp decrease in humidity with altitude can also lead to the formation of a radiation channel.

The effect of säteilykanaalin is often noticed as unusually strong or persistent long-distance radio communication, particularly in VHF and UHF bands. This can be beneficial for amateur radio operators or certain communication systems, allowing signals to propagate far beyond their typical range. Conversely, it can also lead to interference issues, as signals intended for local reception might be received at distant locations. The presence and characteristics of radiation channels are influenced by weather patterns and geographical features.