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Formation of Clouds

Formation of Clouds. A cloud is composed of millions of little droplets of water (or ice crystals when temperature is very low) suspended in the air. There are several major processes for cloud formation. Convection Forceful Lifting Meeting air masses Horizontal motion. Convection :.

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Formation of Clouds

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  1. Formation of Clouds

  2. A cloud is composed of millions of little droplets of water (or ice crystals when temperature is very low) suspended in the air. • There are several major processes for cloud formation. • Convection • Forceful Lifting • Meeting air masses • Horizontal motion

  3. Convection : • When the sun shines, the air at the ground level that contain water vapor is heated and it begins to rise, and as the air rises, it begins to cool. • The water then condenses on tiny suspended particles and forms droplets in the atmosphere.

  4. Convection:

  5. Forceful Lifting (mountains) • When air rises over the mountains, it cools and becomes saturated with water vapor. Condensation occurs and the water vapor becomes liquid. • When the air mass descends on the other side of the mountain, it is more dry and warm.

  6. Meeting of air masses • Not only mountains can force air to rise : when warm air meets a mass of heavier cold air, it is also forced to rise. The boundary between warm and cool air is called a « front ». As the warm air ascends it cools, and then clouds may be formed.

  7. Horizontal motion • Sometimes winds bring warm and moist air into a region. If the warm moist air flows over a much colder surface, it is cooled and moisture will condense and form fog. This mechanism is frequent on the coast of continents.

  8. Types of Clouds • Clouds are classified according to their height above and their appearance from the ground. The following cloud roots and translations summarize the components of this classification: • Cirro- curl of hair, high altitude • Alto- middle altitude • Strato- form in layers • Nimbo – rain, precipitation • Cumulo - heap

  9. High Level Clouds • High level clouds occur above 20,000 feet and are given the prefix “cirro.” Cold tropospheric temperatures the clouds are composed of ice crystals. • Three main types: cirrus, cirrostratus, and cirrocumulus

  10. Mid-level clouds • Appear between 6,500 and 20,000 feet. • Depending on the time of year, temp and altitude these clouds may be composed of liquid water droplets, ice crystals, or a combination of the two. • Two main types are: altostratus and altocumulus

  11. Low-level clouds • Not given a prefix. • Low clouds occur below 6500 feet and normally consist of liquid water droplets or even supercooled droplets, except during cold winter storms when ice crystals comprise much of the clouds.

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