1 / 20

Clouds

Clouds. Water is strange stuff!. Water can occur in 3 states:. Gas - water vapour (invisible) Liquid - water droplets (visible) Solid - ice crystals, hail, snow. What are clouds?. Clouds are formed of tiny droplets of water or ice. Clouds form when water vapour cools and condenses .

minya
Download Presentation

Clouds

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Clouds

  2. Water is strange stuff! Water can occur in 3 states: • Gas - water vapour (invisible) • Liquid - water droplets (visible) • Solid - ice crystals, hail, snow

  3. What are clouds? • Clouds are formed of tiny droplets of water or ice. • Clouds form when water vapour cools and condenses. • The temperature at which condensation occurs is called dew point. • Condensation also requires nucleii (small particles) such as dust.

  4. What happens when air is cooled? • Relative humidity increases. • Dew point is reached (100% relative humidity). • Water vapour (invisible) condenses to form water droplets (visible). • Sometimes the water vapour may change straight into solid state: called sublimation.

  5. Localized Convective Lifting • Localized convective lifting occurs where unequal surface heating causes pockets of air to rise because of their buoyancy.

  6. Cloud Formation Processes that lift air • Convergence • Convergence is when air flows together and rises.

  7. Orographic Lifting • Orographic lifting occurs when mountains act as barriers to the flow of air, forcing the air to ascend. The air cools adiabatically; clouds and precipitation may result.

  8. Cloud Formation Air Compression and Expansion  Adiabatic Temperature Changes • When air is allowed to expand, it cools, and when it is compressed, it warms.  Expansion and Cooling • Dry adiabatic rate is the rate of cooling or heating that applies only to unsaturated air. • Wet adiabatic rate is the rate of adiabatic temperature change in saturated air.

  9. Cloud Formation by Adiabatic Cooling

  10. Cloud Formation Processes That Lift Air  Frontal Wedging • A front is the boundary between two adjoining air masses having contrasting characteristics.

  11. Cloud Types and Precipitation Types of Clouds  Clouds are classified on the basis of their form and height. • Cirrus (cirrus = curl of hair) are clouds that are high, white, and thin. • Cumulus (cumulus = a pile) are clouds that consist of rounded individual cloud masses. • Stratus (stratus = a layer) are clouds best described as sheets or layers that cover much or all of the sky.

  12. Cloud shapes Clouds can be classified by their shape and height Flat clouds eg Stratus (St) Fluffy clouds eg Cumulus (Cu) Wispy clouds eg Cirrus (Ci)

  13. Cloud heights Clouds can also be classified by height of cloudbase Low level (below 2000m) eg stratus Middle level - alto (2,000 to 6, 000m) eg alto-cumulus High level - cirro (above 6,000m) eg cirrus

  14. Cloud Classification

  15. Spot the cloud! Low and flat ….. Stratus

  16. Spot the cloud! Middle level, fluffy ….. Alto -Cumulus

  17. Spot the cloud! High level, wispy ….. Cirrus

  18. Spot the cloud! Rain bearing, storm clouds ….. Cumulo-Nimbus

  19. World cloud patterns Can you explain the major world cloud belts?

More Related