lecture 3: Water in the atmosphere 5

Question 1

Formation of fog

Answer 1

When condensation occurs near the ground, with visibility reduced below 1 km, this is referred to as fog.

Fog formation usually forms

1. by cooling
2. by evaporation and mixing

Question 2

More on formation of fog

Answer 2

Radiation fog: Cooling through night-time radiation and ground conduction.
• Advection fog: Warm moist air moving over a cold surface.
Evaporation (Steam) Fog
• Evaporation (mixing) fog: Warm moist air mixes with cold dry air resulting in saturation

Question 3

Cloud classification

Answer 3

• A cloud is a visible aggregate of tiny water droplets or ice crystals suspended in the air.
Photos: Cloud Appreciation Society
• Clouds exist in seemingly endless variety of forms.
• They are commonly divided into 4 major cloud groups with a total of 10 principal cloud types.