This diagram illustrates the Earth's atmospheric electrical circuit and how it is influenced by weather conditions. Here's a detailed breakdown of its components:
- **Ionosphere**: Shown at the top of the diagram, the ionosphere is a layer of Earth's atmosphere that is ionized by solar radiation and is known to reflect radio waves. It's depicted here as having a positive charge distribution.
- **Earth**: At the bottom, the Earth's surface is shown with a negative charge distribution. This is in line with the natural electric field that exists between the Earth and the ionosphere.
- **Electric Field**: The arrows between the ionosphere and Earth represent the electric field lines, which are directed from the positively charged ionosphere towards the negatively charged Earth.
- **Voltage**: The "250 kV" label indicates the potential difference between the ionosphere and the Earth's surface. This is a typical value for the fair-weather condition and contributes to a continuous current flow in the atmosphere.
- **Fair Weather**: In areas marked as "Fair weather," the electric field lines are uniform and vertical. This is characteristic of regions where the weather is clear, and there is no disturbance in the atmospheric electric field.
- **Corona**: The term "Corona" refers to a phenomenon where a discharge, such as lightning, occurs. It's illustrated here as a discharge from a cloud to the Earth, which can temporarily disturb the electric field.
- **Rain/Thundercloud**: The cloud with "Rain" and lightning symbolizes a thunderstorm, which can significantly influence the atmospheric electric circuit. Lightning is a rapid discharge of this built-up electrical energy.
- **Net Electric Current**: The electric current is shown flowing from the ionosphere to the Earth in fair weather regions and from the Earth to the ionosphere in the region with the thundercloud. The net current is the result of these individual currents.
- **Charge Movement**: The diagram also indicates the movement of positive charges downward in the thundercloud region and the upward movement of negative charges in fair weather regions.
This system is an essential part of the global atmospheric electric circuit, which affects weather and climate. Thunderstorms play a vital role in maintaining the electric field and current in the Earth-ionosphere system. The diagram simplifies complex atmospheric physics into an understandable model.
April 21