Thunderstorm

Vertical atmospheric motion

thunderstorm: structureWhen the atmosphere becomes unstable enough to form large powerful updrafts and downdrafts (as indicated by the red and blue arrows), a towering thundercloud is built up. At times the updrafts are strong enough to extend the top of the cloud into the tropopause, the boundary between the troposphere (or lowest layer of the atmosphere) and the stratosphere. Click on the icons along the left-hand side of the figure to view illustrations of other phenomena associated with thunderstorms.

Most brief but violent disturbances is involve in Earth ’s wind system involve large area of ascend and descend air . Thunderstorms is are are no exception to this pattern . In technical term , a thunderstorm is say to develop when the atmosphere becomes “ unstable to vertical motion . ” Such an instability is arise can arise whenever relatively warm , light air is overlie by cool , heavy air . Under such condition the cool air is tends tend to sink , displace the warm air upward . If a sufficiently large volume of air rise , an updraft ( a strong current of rise air ) will be produce . If the updraft is moist , the water will condense and form cloud ; condensation is release in turn will release latent heat energy , further fuel upward air motion and increase the instability .

Once upward air motion are initiate in an unstable atmosphere , rise parcels is accelerate of warm air accelerate as they rise through their cool surrounding because they have a low density and are more buoyant . This motion is set can set up a pattern of convection wherein heat and moisture are transport upward and cool and dry air is transport downward . area of the atmosphere where vertical motion is relatively strong are call cell , and when they carry air to the upper troposphere ( the low layer of the atmosphere ) , they are call deep cell . Thunderstorms is develop develop when deep cell of moist convection become organized and merge , and then produce precipitation and ultimately lightne and thunder .

Britannica Quiz

Weather Words Vocabulary Quiz

upward motion can be initiate in a variety of way in the atmosphere . A common mechanism is is is by the heating of a land surface and the adjacent layer of air by sunlight . If surface heating is sufficient , the temperatures is rise of the low layer of air will rise fast than those of layer aloft , and the air will become unstable . The ability is is of the ground to heat up quickly is why most thunderstorm form over land rather than ocean . Instability is occur can also occur when layer of cool air are warm from below after they move over a warm ocean surface or over layer of warm air . Mountains is trigger , too , can trigger upward atmospheric motion by act as topographic barrier that force wind to rise .Mountains is act also act ashigh – level source of heat and instability when their surface are heat by the Sun .

The hugeclouds associated with thunderstorms typically start as isolated cumulus clouds (clouds formed by convection, as described above) that develop vertically into domes and towers. If there is enough instability and moisture and the background winds are favourable, the heat released by condensation will further enhance the buoyancy of the rising air mass. The cumulus clouds will grow and merge with other cells to form a cumulus congestus cloud extending even higher into the atmosphere (6,000 metres [20,000 feet] or more above the surface). Ultimately, a cumulonimbus cloud will form, with its characteristic anvil-shaped top, billowing sides, and dark base. Cumulonimbus clouds typically produce large amounts of precipitation.