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Atmospheric pressure decreases with altitude, so the rising air expands in a process that expends energy and causes the air to cool, which makes water vapor condense into cloud. [8] Water vapor in saturated air is normally attracted to condensation nuclei such as dust and salt particles that are small enough to be held aloft by normal ...
Because of their differential buoyancy relative to surrounding cloud-free air, clouds can be associated with vertical motions of the air that may be convective, frontal, or cyclonic. The motion is upward if the clouds are less dense because condensation of water vapor releases heat, warming the air and thereby decreasing its density.
Clouds form as relatively warmer air carrying moisture rises within cooler air. As the moist air rises, it cools, causing some of the water vapor in the rising packet of air to condense . [ 4 ] When the moisture condenses, it releases energy known as the latent heat of vaporisation, which allows the rising packet of air to cool less than its ...
Atmospheric thermodynamics is the study of heat-to-work transformations (and their reverse) that take place in the Earth's atmosphere and manifest as weather or climate. . Atmospheric thermodynamics use the laws of classical thermodynamics, to describe and explain such phenomena as the properties of moist air, the formation of clouds, atmospheric convection, boundary layer meteorology, and ...
The percentage of water vapor in surface air varies from 0.01% at -42 °C (-44 °F) [15] to 4.24% when the dew point is 30 °C (86 °F). [16] Over 99% of atmospheric water is in the form of vapour, rather than liquid water or ice, [17] and approximately 99.13% of the water vapour is contained in the troposphere.
Consequently, without the sun's heat, air cools, causing water droplets (or clouds) to revert to invisible vapor. "Along with the sudden darkness came a change in the clouds' color," Rao wrote of ...
A typical raindrop is about 2 mm in diameter, a typical cloud droplet is on the order of 0.02 mm, and a typical cloud condensation nucleus is on the order of 0.0001 mm or 0.1 μm or greater in diameter. [1] The number of cloud condensation nuclei in the air can be measured at ranges between around 100 to 1000 per cm 3. [1]
Low, ragged clouds that appear beneath the main cloud base. Formed from moist air lifted by outflow winds from a storm. Often mistaken for tornadoes, but they are typically harmless, indicating ...