Clouds

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Cloud Formation
Presented by:
Maida Kanwal (17)
Hira Sumbal (15)
Zunaira Nawaz (21)
Sheeren Rehman (31)
Um e Laila (09)
Aarfa Tufail (11)
What are clouds?
Clouds:
A cloud is a visible mass of liquid
droplets or frozen crystals made of water or
various chemicals suspended in the
atmosphere above the surface of a planetary
body. These suspended bodies are called as
aerosols.
Types of clouds
Luke Howard’s Classification: (1803)
Luke Howard has been called the Father of Meteorology. He was the first
man to classify clouds. World Meteorological Organization (WMO) has
extended Luke Howard’s classification to make 10 main groups of clouds.
High level
clouds
• Cirrus.
• Cirrocumulus, Cirrostratus.
Mild level
clouds
• Altocumulus.
• Altostratus, Nimbostratus.
Low level
clouds
• Stratocumulus, Cumulonimbus.
• Stratus, Cumulus.
Types of clouds
Names for clouds:
The names for clouds are usually combinations of the
following prefixes or suffixes:
 Stratus/ Strato = Flat or layered and smooth.
 Cumulus/ Cumulo = Heaped up or puffy, like
cauliflower.
 Cirrus/ Cirro = High up or wispy.
 Alto = Medium level.
 Nimbus/ Nimbo = Rain-bearing cloud.
Types of clouds
1- High Level Clouds:
Above 20,000 feet, composed of ice crystals, thin
and white in appearance.
2- Mild Level Clouds:
Between 6000-20,000 feet, composed of water
droplets, grey to pale blue in appearance.
Types of clouds
3- Low Level Clouds:
Below 6,000 feet, composed of water
droplets, may contain ice crystals, light grey in
appearance.
The water cycle
The Water Cycle consists of 4 main processes:
1- Evaporation:
High temperature cause evaporation of water
from water bodies, i.e. Oceans, Rivers, Lakes etc.
2- Transpiration:
Transpiration, loss of water from plants, enters
water into the the atmosphere.
The water cycle
3- Condensation:
The air and water droplets condense and
clouds are formed.
4- Precipitation:
The clouds looses their water in the form of
rain, hail, snow. This is how water is returned
back to ground and cycle continues.
Cloud formation
Process:
Cloud formation occurs through convection. As the intensity of
solar radiation increases, the warmer air becomes lighter and
moves upward. As this happens, the temperature decreases, so
does the amount of water vapors air can hold. Due to this, the
process of condensation starts. These vapors rapidly condense and
soon clouds — composed of countless billions of tiny water
droplets or ice crystals — result. Clouds are occasionally produced
by a reduction of pressure aloft or by the mixing of warmer and
cooler air currents.
Cloud formation
 Clouds are formed at different heights.
 The characteristics of clouds are formed by
the elements available, including the
amount of water vapors, the temperature at
that height, the wind, and the interplay of
other air masses.
Factors influencing Cloud Formation
Factors which influence cloud formation
are:





Surface heating.
Topography forcing.
Frontal.
Convergence.
Turbulence.
Factors influencing Cloud Formation
 Surface Heating:
The increase in temperature heats the ground and
the air in contact with it which rises and form clouds
(Cumulus).
 Topography:
The shape and features of the area - can cause
clouds to be formed. When air is forced to rise over a
barrier of mountains or hills it cools as it rises resulting
in cloud formation.
Factors influencing Cloud Formation
 Frontal:
Clouds are formed when a mass of warm air rises up
over a mass of cold, dense air over large areas along
fronts.
 Convergence:
Streams of air flowing from different directions are
forced to rise where they flow together, or converge.
 Turbulence:
A sudden change in wind speed with height creating
turbulent eddies in the air.
Impact of clouds on Environment
 Clouds cool Earth's atmosphere by absorbing heat
emitted from the surface and radiating it to the space.
 Clouds help redistribute extra heat from the equator
toward the poles.
 Clouds indicate what type of atmospheric processes are
occurring. For Example, Cumulus Clouds indicate
surface heating and atmospheric turbulence.
Impact of clouds on Environment
 The reflection of sunlight from different kinds of
clouds can cool Earth’s atmosphere.
 Clouds are required for precipitation and
essential for hydrological cycle.
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