Clouds Why is the sky blue? "White" sunlight enters the atmosphere molecules in the air are just the...
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Transcript of Clouds Why is the sky blue? "White" sunlight enters the atmosphere molecules in the air are just the...
Clouds
Why is the sky blue?
• "White" sunlight enters the atmosphere
• molecules in the air are just the right size to scatter light from the blue end of the visible spectrum.
• The other colors pass through
And Clouds Are White Because...?
...the water droplets that make up clouds are much larger than the molecules that scatter blue light. The clouds scatter and reflect all the visible colors of light that strike them.
And Clouds Are Gray Because...?
• if the cloud is thick enough, light does not penetrate completely through the cloud, resulting in dark, heavy-looking cloud bottoms
Why do clouds form? • Clouds are nothing more than
water vapor that condenses into a visible form.
• The sun heating the earth’s surface evaporates water to the atmosphere where it cools and condenses.
Classification of Clouds
• Clouds are classified by Form Altitude
• Three forms Stratus Cirrus Cumulus
• Three altitudes Low, middle,
high
Cloud Types
Latin Root Translation Example
Cumulus heap cumulus
stratus layer altostratus
Cirrus curl of hair cirrus
Nimbus rain cumulonimbus
Alto high altostratus
Stratus• Sheetlike or
layered clouds.• Lowest in the
sky.• Light or dark
gray, covering most of the sky,
• Includes fog.
Stratus
• Uniform, thick to thin layered clouds
• Below 6,000 feet
Stratus
Stratus
Altostratus
• Thin, uniform, sometimes with "wide corduroy" appearance
• 6,000 - 20,000 feet
Nimbostratus
Stratocumulus
• Broad and flat on the bottom, puffy on top
• Below 6,000 feet
Cumulus
• Puffy clouds • Below 6,000
feet
Cumulus
Fair Weather Cumulus
• Appearance of floating cotton
• Lifetime of 5 – 40 minutes
Cumulus
Cumulonimbus
• Appear as Thunderheads
• Located near ground to above 50,000 feet
Cumulonimbus
Cumulonimbus
Upward developing cloud
Altocumulus
• Medium-sized puffy clouds
• 6,000 - 20,000 feet
Altocumulus
Altocumulus
Cirrus
• Appear thin, wispy, often with a “mare's tail”
• Above 18,000 feet
Cirrostratus
• Appear as thin, layer, above thunderheads
• Above 18,000 feet
Cirrocumulus
• Small puffy clouds
• Above 18,000 feet
Cloud Levels
Fog
Radiation Fog
• Results from the cooling of air that is in contact with the ground.
• Due to nightly cooling of the Earth.
Advection Fog
• condensation of water vapor that results from the cooling of warm moist air as it moves across a cold surface.
Upslope Fog
• results from the lifting and adiabatic cooling of air rising up a slope of land.
Steam Fog• Condensation of
water vapor.
• Results from cool air moving over a warm body of water, lake or stream.
Drizzle
• Precipitation consisting of small drops, smaller than .5mm in diameter
Precipitation
• Sleet – ice pellets that form when rain falls through a layer of freezing air.
• Glaze Ice – thick layer of sheet ice formed when rain freezes when it contacts a surface.
Hail• Precipitation in
the form of ice.• Grows as
frozen water travels up and down in a cloud.
• Combination of different sized cloud droplets to form larger droplets.
Coalescence
• Supercooling.• process by which water droplets
are induced to remain liquid below 0°C .
• Freezing Nuclei.• condensation nuclei with a
crystalline structure like that of ice.
Cloud Seeding
• Addition of freezing nuclei to supercooled clouds in an attempt to induce or increase precipitation.
Special Clouds:Lenticular
Mammatus
Noctilucent