Spark discharges and spark flashovers are responsible for the natural phenomena of sheet lightning and lightning. Both lightning and sheet lightning belong to the group of electrometeors. Appropriate phenomena present themselves as visual or audible sequelae occurring in response to atmospheric electricity.
Sheet lightning: a thunderless weather phenomenon that makes the atmosphere and nocturnal horizon flicker and shine impressively
Characteristic of the weather phenomenon of sheet lightning, which occurs during the course of the night, is a comparatively flat, almost linearly appearing illumination, which the viewer perceives as potential “cloud-to-cloud flashes” that illuminate the sky or the air layers with the help of horizontally fading “Cloud Lightning” illuminate. The nocturnal weather phenomenon can often be observed before or after a thunderstorm, so that sheet lightning can be classified as an objective indicator of an approaching or departing thunderstorm. The respective point of observation of sheet lightning is basically linked to a relatively large distance to the point of the electrical discharge. According to scientists, the thunderless weather phenomenon can be observed at a distance of at least 18 km from the thunderstorm.
People who register the phenomenon on the night horizon are therefore at a location that is at least 18 km away from the location of the thunderstorm. Viewers of sheet lightning therefore only experience thunderless reflections in the cloud area. Days characterized by muggy, warm, sunny weather increase the likelihood of nocturnal sheet lightning.
Lightning within storm clouds also forces atmospheric flickering
In addition, lightning within the thunderclouds or “cloud-area-lightning”, which generally takes place within a cloud, favor the natural phenomenon.
Due to the electrically differently charged raindrops within a thundercloud, pronounced charge differences prevail there. Therefore, the clouds are dominated by permanent electrical tension. If this is above average, it discharges in the form of lightning or following the lightning channel within the cloud. Because such flashes are surrounded by water droplets and ice crystals embedded in the clouds, the clouds in such situations scatter the light and produce the atmospheric flickering typical of sheet lightning.
Lightning: incandescent, luminous spark discharges with tremendous power
Lightning, like sheet lightning, belongs to the category of electrometeors. They are caused by atmospheric electricity. A lightning bolt is therefore fundamentally linked to an air-electric discharge. Flashovers between clouds that have opposite charges or distinct charge differences, or clouds and the earth's surface are considered lightning.
Consequently there are “cloud-to-cloud-flashes” or “cloud-surface-flashes” and “cloud-to-earth-flashes”. There are also gigantic lightning bolts that discharge as part of thunderstorms above the cloud towers, at the outer edge of the earth's atmosphere, reaching up to space and illuminating it. Lightning researchers dub such phenomena as Blue Jets, Red Sprites, and Elves. Corresponding phenomena can be assigned to the category of “Transient Luminous Events” (fleeting light events). While blue jets occur in the stratosphere, lightning researchers register red sprites in the mesosphere and elves in the ionosphere. Different types of lightning therefore influence thunderstorm events.
Lightning heats the air around the lightning channel directly or within microseconds to +30000 °C. The intense heat promotes the expansion of the air masses in the area of the lightning channel and creates a sound wave that humans perceive as thunder. The origin of thunder is therefore lightning or electrical discharge.
The lightning process is divided into preliminary and main discharge
The lightning process is divided into processes of preliminary and main discharge.< p>The starting point in this regard is marked by the pre-discharges that create the discharge channel. This is followed by the process of the main discharge, which takes place within a few tenths of a second after the pre-discharge. Countless partial discharges, which take place at intervals of thousandths of a second, characterize the phase of the main discharge. “Cloud-Earth-Lightning”, which means the flashovers between clouds and the earth's surface, usually show two different main lightning channels that run towards each other. In principle, the main lightning channel emanating from the earth's surface is the first to occur.