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Thunder is the sound caused by lightning. [1] [2] [3] Depending upon the distance from and nature of the lightning, it can range from a long, low rumble to a sudden, loud crack. The sudden increase in temperature and hence pressure caused by the lightning produces rapid expansion of the air in the path of a lightning bolt. [4]
The energy is almost perfectly reflected from earth surface 4 or 5 times with increase dispersion and diminishing amplitude. Along such long paths the speed of propagation of energy is between c/10 to c/100 (where c is the speed of light) and the exact value depends upon frequency.
A lightning channel with all its branches and its electric currents behaves like a huge antenna system from which electromagnetic waves of all frequencies are radiated. . Beyond a distance where luminosity is visible and thunder can be heard (typically about 10 km), these electromagnetic impulses are the only sources of direct information about thunderstorm activity on the gr
Positive lightning is less common than negative lightning and on average makes up less than 5% of all lightning strikes. [10] A bolt from the blue lightning strike which appears to initiate from the clear, but [clarification needed] the turbulent sky above the anvil cloud and drive a bolt of plasma through the cloud directly to the ground. They ...
Notice that the plotted lines are spaced in 10 dB increments at 1 MHz. Atmospheric noise is radio noise, or "static", caused by natural atmospheric processes, primarily lightning discharges in thunderstorms. On a worldwide scale, there are about 40 lightning flashes per second, or ≈ 3.5 million lightning discharges per day. [2]
When a sufficiently large positive lightning strike carries charges to the ground, the cloud top is left with a strongly negative net charge. This can be modeled as a quasi-static electric dipole and for less than 10 milliseconds a strong electric field is generated in the region above the thunderstorm.
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It originates from a mass of storm clouds at an altitude of more than 1 km (0.6 mi), and occurs for 140 to 160 nights a year, nine hours per day, and with lightning flashes from 16 to 40 times per minute. [3]