You searched for: “cloud
cloud, clouds
The collection of water droplets or ice crystals suspended in the air, which forms when the air is cooled to its dew point and condensation occurs.
This entry is located in the following unit: Meteorology or Weather Terms + (page 2)
Word Entries containing the term: “cloud
cloud enhancement
The increase in solar intensity caused by reflected irradiance (sending forth radiant light) from nearby clouds.
This entry is located in the following unit: Photovoltaic Conversion Efficiency Terms + (page 4)
cloud formations
Clouds exist in three layers in the lower atmosphere; therefore, with four types of clouds and three layers, there are up to twelve major cloud types that have evolved from Luke Howard's pioneering work:

Heaps: Cumulus family clouds:
  • Fair weather cumulus
  • Swelling cumulus
  • Cumulus congestus

Layers: Stratus family clouds:
  • Altostratus
  • Cirrostratus

Layered Heaps clouds:
  • Stratocumulus
  • Altocumulus
  • Cirrocumulus

Precipitating clouds:
  • Cumulonimbus
  • Cirrus
  • Nimbostratus
This entry is located in the following unit: Meteorology or Weather Terms + (page 2)
cloud seeding
The use of substances to increase precipitation; silver iodide and dry ice are often used.

The process has never been very successful.

This entry is located in the following unit: Meteorology or Weather Terms + (page 2)
cloud terminology
Englishman, Luke Howard gave clouds their common names.

Before 1800, observers spoke of clouds only as essences floating in the sky. Clouds had no names and were not well understood.

Luke Howard noted that there are three basic shapes to clouds: heaps of separated cloud masses with flat bottoms and cauliflower tops, which he named cumulus, Latin for "heap"; layers of clouds which are much wider than they are thick, like a blanket or a mattress, which he named stratus, Latin for "layer"; wispy curls, like a child's hair, which he called cirrus, Latin for "curl". To clouds generating precipitation, he gave the name nimbus, Latin for "rain".

This entry is located in the following unit: Meteorology or Weather Terms + (page 2)
contrail cloud
This type of cloud didn't exist in Luke Howard's time because contrails, or "condensation trails", are formed from the vapor expelled into the atmosphere from jet planes flying at high altitudes.

The cold temperatures in the upper atmosphere turn aircraft vapor into ice crystals that look like cirrus clouds.

This entry is located in the following unit: Meteorology or Weather Terms + (page 3)
funnel cloud
A rotating extension of a cloud that touches, or does not touch the ground; usually, associated with clouds that have the potential to form tornadoes or waterspouts.
This entry is located in the following unit: Meteorology or Weather Terms + (page 4)
Luke Howard, 1772-1864, the man who classified cloud types

Up until about 1800, there were no general classifications of clouds

Clouds were referred to poetically or as vague essences floating in the sky.

As an English manufacturing chemist and pharmacist, Luke Howard, like many who observed and studied the workings of the atmosphere at that time, was an amateur meteorologist.

Although he produced several landmark works including On the Modification of Clouds, The Climate of London, and Seven Lectures on Meteorology, the first textbook about weather, he was never trained as a scientist but from an early age, he had a fondness for nature and the weather, particularly the clouds.

Luke Howard divided clouds into basic shapes with Latin classifications: cumulus, stratus, cirrus, and nimbus.
Each cloud type is formed under different conditions.

His fascination with clouds started with the incredible skies of 1783 between May and August of that year. The Northern Hemisphere sky was filled with a "Great Fogg", a haze composed of dust and ash that caused brilliant sunrises and sunsets which resulted from the violent volcanic eruptions in Iceland (Eldeyjar) and Japan (Asama Yama).

In addition to the spectacle of the continuous volcanic ash in the sky, there was a fiery meteor which flashed across western European skies during the early evening of August 18, which was observed by the eleven year-old Luke Howard.

Before the beginning of the Nineteenth Century, most weather observers believed that clouds were too transient, too changeable, and too short-lived to be classified or even analyzed.

With few exceptions, no cloud types were named; they were just described by their color and form as each individual saw them: dark, white, gray, black, mare's tails, mackerel skies, wooly fleece, towers and castles, rocks and oxes-eyes.

Clouds were used in a few situations as weather forecasting proverbs, but mostly by their state of darkness or color:

"Red sky in morning, sailor take warning."

"Mackerel skies and mare's tails, make lofty ships carry low sails."


—Excerpts compiled from
Weather Doctor's Weather People and History;
Luke Howard: The Man Who Named the Clouds
and
— "The Father of Clouds" by Anne H. Oman in
Weather Nature in Motion; National Geographic Society;
Washington, D.C.; 2005; page 58.
This entry is located in the following unit: Meteorology or Weather Terms + (page 5)
Oort cloud
A cloud of comets lying about 50,000 to 100,000 astronomical units from the sun.

The Oort cloud is postulated as the source of comets entering the solar system and is named after the Dutch astronomer Jan Oort, who theorized its existence in 1950.

The Oort Cloud is a spherical region extending for trillions of miles or kilometers that contains debris flung outward by the giant planets after they formed.

It is believed that comets that orbit the sun in periods of thousands or millions of years usually come from the Oort Cloud.

—Compiled from information presented in
Astronomy, The World Book Encyclopedia of Science;
World Book, Inc.; 2000; page 93.
This entry is located in the following unit: Astronomy and related astronomical terms (page 17)