Bio 120: Lecture 22, 23 Air, Water, and Weather
The Atmosphere – see several diagrams drawn on the board
Air
• Gases, vapor, and particles
• Properties of air:
– Warm air is less dense (lighter) than cooler air
– Humid air is less dense than dry air
Humid air “floats”
Water
• Molecule of life!
• Molecules in motion
– Due to heat energy
• 3 phases
– Gas (vapor) - fastest
– Liquid (water) - faster
– Solid (ice) - slowest
Relative Humidity
• The relative amount of moisture in the air
• Warmer air can carry more moisture than cooler air
Dew Point
• Measure of how much water is in the air.
• As air cools:
– Carries less water
– Condensation occurs
• Can produce “dew”
Clouds
•
Form by condensation of water vapor in atmosphere
- water condenses onto tiny particles in the air
Cloud Forms
– Cirrus
•
High, white, whispy
– Cumulus
Globular
– Stratus
• In layers/sheets
•
Cloud Type = Form + Level
•
High level
(> 20,000 ft)
- made of ice crystals
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Bio 120: Lecture 22, 23 Air, Water, and Weather
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– Cirrus
Falling ice crystals blown into wisps (called ”mare’s tails”, or “painter’s brushes”
– Cirrocumulus
• Like blurry cotton balls (also called “mackerel sky”, or “buttermilk sky”
•
•
Medium level
(6,500 – 20,000 ft)
- made of ice crystals or water
– Altostratus
• Gray sheet; continuous, featureless sheet, “hazy” or “overcast” conditions
– Nimbostratus
• Rain/snow clouds
• Dark; Can be lower
•
Low level
(< 6500 ft)
- made of water
– Stratocumulus
• Pillow-like clouds with flat bottom – blown by surface winds
– Fog
• Touches the ground
•
Towering (can extend through all levels)
– Cumulonimbus
- Thunderstorm clouds
Water moderates coastal temperatures
- See diagram of Sea breezes drawn on board
For July 2006:
- Paso Robles, CA
Avg Daily High: 92.3
Avg Daily Low: 54.3
- Santa Barbara, CA
Avg Daily High: 73.9
Avg Daily Low: 56.2
Marine Layer Fog (See board Drawings)
- “May Gray” and “June Gloom”
PrecipitationCloud droplets join together and fall
Rain Shadow Effect –
Produces California’s deserts