Suchergebnisse
Suchergebnisse:
Übersetzung Portugiesisch-Deutsch für tempestade im PONS Online-Wörterbuch nachschlagen! Gratis Vokabeltrainer, Verbtabellen, Aussprachefunktion.
Übersetzung für 'tempestade' im kostenlosen Portugiesisch-Deutsch Wörterbuch und viele weitere Deutsch-Übersetzungen.
- Overview
- Vertical atmospheric motion
- GeneratedCaptionsTabForHeroSec
thunderstorm, a violent short-lived weather disturbance that is almost always associated with lightning, thunder, dense clouds, heavy rain or hail, and strong gusty winds. Thunderstorms arise when layers of warm, moist air rise in a large, swift updraft to cooler regions of the atmosphere. There the moisture contained in the updraft condenses to form towering cumulonimbus clouds and, eventually, precipitation. Columns of cooled air then sink earthward, striking the ground with strong downdrafts and horizontal winds. At the same time, electrical charges accumulate on cloud particles (water droplets and ice). Lightning discharges occur when the accumulated electric charge becomes sufficiently large. Lightning heats the air it passes through so intensely and quickly that shock waves are produced; these shock waves are heard as claps and rolls of thunder. On occasion, severe thunderstorms are accompanied by swirling vortices of air that become concentrated and powerful enough to form tornadoes.
Thunderstorms are known to occur in almost every region of the world, though they are rare in polar regions and infrequent at latitudes higher than 50° N and 50° S. The temperate and tropical regions of the world, therefore, are the most prone to thunderstorms. In the United States the areas of maximum thunderstorm activity are the Florida peninsula (more than 80 thunderstorm days per year, with some areas over 100), the Gulf Coast (60–90 days per year), and the mountains of New Mexico (50–80 days per year). Central Europe and Asia average 20 to 60 thunderstorm days per year. It has been estimated that at any one moment there are approximately 1,800 thunderstorms in progress throughout the world.
Most brief but violent disturbances in Earth’s wind systems involve large areas of ascending and descending air. Thunderstorms are no exception to this pattern. In technical terms, a thunderstorm is said to develop when the atmosphere becomes “unstable to vertical motion.” Such an instability can arise whenever relatively warm, light air is overlain by cooler, heavier air. Under such conditions the cooler air tends to sink, displacing the warmer air upward. If a sufficiently large volume of air rises, an updraft (a strong current of rising air) will be produced. If the updraft is moist, the water will condense and form clouds; condensation in turn will release latent heat energy, further fueling upward air motion and increasing the instability.
Britannica Quiz
Facts You Should Know: Weather Quiz
Once upward air motions are initiated in an unstable atmosphere, rising parcels of warm air accelerate as they rise through their cooler surroundings because they have a lower density and are more buoyant. This motion can set up a pattern of convection wherein heat and moisture are transported upward and cooler and drier air is transported downward. Areas of the atmosphere where vertical motion is relatively strong are called cells, and when they carry air to the upper troposphere (the lowest layer of the atmosphere), they are called deep cells. Thunderstorms develop when deep cells of moist convection become organized and merge, and then produce precipitation and ultimately lightning and thunder.
Upward motions can be initiated in a variety of ways in the atmosphere. A common mechanism is by the heating of a land surface and the adjacent layers of air by sunlight. If surface heating is sufficient, the temperatures of the lowest layers of air will rise faster than those of layers aloft, and the air will become unstable. The ability of the ground to heat up quickly is why most thunderstorms form over land rather than oceans . Instability can also occur when layers of cool air are warmed from below after they move over a warm ocean surface or over layers of warm air. Mountains, too, can trigger upward atmospheric motion by acting as topographic barriers that force winds to rise. Mountains also act as high-level sources of heat and instability when their surfaces are heated by the Sun.
Exclusive academic rate for students! Save 67% on Britannica Premium.
Learn about thunderstorms, violent weather disturbances that produce lightning, thunder, and precipitation. Find out how they form, where they occur, and what effects they have on the atmosphere.
12. Sept. 2023 · Aus urheberrechtlichen Gründen können wir Ihnen die Texte der Artikel nicht zur Verfügung stellen. Bitte nutzen Sie die Online-Angebote der entsprechenden Medien.
Learn the meaning and usage of the Portuguese word tempestade in English. Find out how to say tempestade in different contexts, such as meteorology, figurative language and idioms.
tempestade (Portugiesisch):
28. Mai 2024 · O Atlântico Norte pode enfrentar até sete grandes furacões de categoria três ou superior este ano, mais que o dobro do número usual, advertiu a agência meteorológica dos EUA, NOAA ...
