Transcript
Clouds and Precipitation
Adiabatic Temp. Change and Expansion and cooling
• Unsaturated air• Wet adiabatic rat is always lower than dry • Temp. changes happen even if heat isn’t
added or subtracted.
Orographic Lifting
• Occurs when elevated terrains act bas barriers to the air flow.
• Air goes up a mountain slope, is compresses and cooling often generates clouds.
• Many rainiest places have windward slopes.
Frontal Wedging
• Masses of warm air and cold air collide• Denser air acts, less dense air rises • Middle-latitude are used for storm systems
Convergence
• Air masses forces air to rise• The lower it is, it starts to lift• Warm days the air is from the ocean to the
land
Localized Convective Lifting
• Warm days, unequal heating of Earths surface may cause some pockets of air to be warmed
• Warming of air is called thermal • Process the products rising thermals is
localizes convection lifting.
Stability
• Air is forced to rise• Temperature would drop because of expansion• Volume of air was cooler than the surrounding
environment.
Condensation
• Happens when water vapor in the air changes to a liquid
• For condensation to occur, the air must be saturated
• Saturated occurs at dew point or when water vapor is added in the air
Types of clouds
• Cirrus- clouds are high, white, occur ad patches
• Cumulus- consist if rounded individual cloud mass, have flat bases
• Stratus- are like sheets, or a layer that covers most the of sky
High Clouds
• All high clouds are thin & white. • Temperature is low with small quantities of
water vapor presents a high altitude• Clouds are not considered precipitation
markers
Middle clouds
• Range to 2000 to 6000 meters • Have prefix of alto • White to grayish color of sheet
Low Clouds
• Stratus, Stratocumulus, and Nimbostratus• cloud growth is a type in common when air id
forced upwards• Stable air can result in a cloud layer that is
largely horicaontal
Clouds Of Vertical Development
• Clouds don’t fit into any of the three height categories.
• Have bases in low height range but extended upward
• Once upward movement is triggered, acceleration is powerful, clouds with great vertical rang form.
Fog
• No difference between fog and a cloud• Defined as a cloud • When fog is dense, visibility may be few dozen
meters for less
Cold Clouds Precipitation
• Relies on two physical processes: super cooling and supersaturating
• Cloud droplets to not freeze at 0c • Rainfall can deal with clouds located below
the freeing point
Warm Clouds Precipitation
• Mechanism forms raindrops, in the collision-coalscence process
• Salt can remove water vapor form the air• Large droplets move through clouds, collide
and coalesce
Rain and Snow • Rain mean drops of water falling from clouds• Snow melt and continue their descent as rain
before they reach the ground• Light, fluffy snow made up of individual six-
sides ice crystals
Sleet, Glaze and hail
• Sleet is the fall of small particles of clear to translucent ice
• Glaze is known for freezing rain, raindrops become super-cooled
• Hail is produced in cumulonimbus clouds, hailstones begin as small ice pellets that grow by collection super-cooled water droplets