Post on 10-Jul-2015
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