Overview
The lecture explains the importance of clouds in Earth's environment, their main types, classification systems, and unique cloud phenomena.
Importance of Clouds
- Clouds are essential for delivering fresh water to land through rain.
- Without clouds, most land would be dry and unsuitable for drinking water or agriculture.
- Clouds help regulate climate by reflecting sunlight and cooling the earth.
Main Cloud Types
- Cumulus: Puffy, white clouds forming low (under 2,000 meters); can grow vertically.
- Stratus: Flat, featureless layers in the lower atmosphere, commonly making skies "cloudy"; reflect sunlight widely.
- Cirrus: Wispy clouds found very high (7,000–14,000 meters), made mostly of ice crystals, often precede storms.
Cloud Prefixes and Modifiers
- Alto: Indicates mid-level clouds (2,000–7,000 meters).
- Ciro/Cero: Used for clouds above 7,000 meters; "very high".
- Nimbus: Denotes rain clouds (e.g., cumulonimbus, nimbostratus).
- Strato and Cumulo: Used for hybrid forms like stratocumulus.
Major Cloud Species and Special Forms
- Species exist within each main type (e.g., cirrus fibratus, cumulus humilis, cumulonimbus capillatus).
- Special forms include lenticular (saucer-shaped), mammatus (pouch-like), and fractus (fragmented by wind).
- Stratocumulus: Most common worldwide, combining stratus and cumulus features.
- Cumulonimbus: Can grow through all layers, cause thunderstorms, and supercells, and may create tornadoes.
- Asperitas: A newly recognized rare cloud with dramatic waving or rolling undersides.
Unique Cloud Phenomena
- Iridescent clouds: Show colors due to light scattering.
- Morning Glory: Rare wave clouds in Australia, possibly caused by Kelvin-Helmholtz waves.
- Pileus: Cap clouds that form over rapidly growing other clouds, like cumulonimbus or even volcanic ash.
Key Terms & Definitions
- Cumulus — Puffy, heap-like cloud type forming low in the atmosphere.
- Stratus — Flat, layered cloud stretching horizontally.
- Cirrus — High, wispy, ice-crystal cloud.
- Alto — Prefix for mid-level clouds (2,000–7,000 meters).
- Nimbus — Prefix or suffix denoting rain-producing clouds.
- Lenticular — Lens or saucer-shaped stationary cloud, often near mountains.
- Mammatus — Cloud with pouch-like projections underneath.
- Cumulonimbus — Large, vertically developed storm cloud capable of producing severe weather.
Action Items / Next Steps
- Review the cloud classification system and be able to identify main types and modifiers.
- Practice recognizing different cloud species and special phenomena in the sky.
- Prepare for quiz on cloud types, their formations, and their impact on weather and climate.