Transcript Cloud formation

Cloud formation
Vertical Temperature Changes
• Air must cool for water to condense
• Water vapor in air will condense (turn to liquid) once it
cools to dew point temp.
• Lifted condensation level: height where condensation
occurs
How does air rise?
There are 3 process that lift air
1. Convection: Warm air rises due to its lower
density
2. Orographic lifting: air encounters mountains and
moves over them
3. Frontal wedging: Warm air ramping over cold air
4. Convergence: Air collides from different
directions and rises
Processes That Lift Air
Clouds Form
• Remember, when air cools to its dew point, air
becomes saturated (rel. humidity 100%)
• Water vapor needs a surface to cling to in order
to become liquid
• Condensation nuclei: solid particles water
condenses upon
– Ex/ salt, dust, & smoke
• If these are present, clouds form
Latent Heat & Stability
• Latent heat: stored heat released during phase
changes
• When water vapor condenses it releases heat
• Stability: ability of air to resist rising
– Air warmer than surrounding air will rise
– Latent heat released causes air to warm and rise
– Clouds will build higher and storms build
Precipitation
• Typical cloud droplets are 7 times less wide than
a human hair
• Coalescence: droplets collide & join together
• When they get too big they fall as precipitation
(rain, snow, sleet or hail)
Water Cycle
• Water Cycle: process where water circulates from
Earth’s surface to the atmosphere and back
• Evaporation: water turns from liquid to gas
• Condensation: water turns back to a liquid (clouds)
• Precipitation: water falls back to surface
• Runoff: water flows along the surface to oceans,
seas & lakes
• Groundwater: water soaks into the ground and
flows towards rivers, lakes, seas, & oceans
Water Cycle
Cloud Types
Clouds
•
Clouds: millions of tiny liquid/ice
water droplets
•
Classified by 2 characteristics
1. Shape
2. Height
Cloud Types
Cloud Shapes
• Cirrus: high, wispy, white clouds
• Stratus: layers that cover the whole sky
• Cumulus: big puffy clouds usually
clusters
Cirrus
Stratus
Cumulus
Cloud Heights
• Very high clouds (above 6000m, or 20,000ft)
– Use the word, Cirrus, as a prefix
• cirrostratus
• cirrocumulus
• Mid-height Clouds (2000m-6000m, or 6000-20,000ft)
– Use the prefix Alto
• Altocumulus
• altostratus
• Low Clouds (below 2000m, or 6000ft)
– Use prefix Stratus
• Stratocumulus
Altocumulus/Stratocumulus
Stratus/Nimbostratus
Cirrus/Cirrostratus
Storm Clouds
• Prefix Nimbus refers to rain producing
clouds
• Begin forming at low heights & can build to
incredible heights
• Referred to as cumulonimbus
• Often produces T-storms & showers
Cumulonimbus
Unique Cloud Formations
Mammatus clouds
Lenticular Cloud
Lenticular Cloud