Classification

Types of precipitation include:

• Rain
• Hail
• Sleet (not present in Hong Kong)
• Snow (not present in Hong Kong)

General Steps

1. Warm air converges, rises up, expands to form uprising air currents.
2. As warm air rises, it falls by 6 degrees Celsius per 1000 m. Relative humidity increase.
3. At the condensation level, relative humidity reaches 100%, or due point. The air is said to be saturated.
4. Excess water vapour condenses on condensation nuclei. Water droplets form.
5. Water droplets accumulate to form clouds.
6. When the clouds are too heavy to support, the droplets fall as rain.
7. Sometimes accompanied by thunderstorms or lightning.

Three Types of Rain

For each of the following types of rain, warm air rises for different reasons.

Frontal Rain

• A cold front occurs when a warm air mass and a cold air mass meet.
• The warm air mass is forced up by the cold air mass.

HKDSE Geography : Elective 2 - Weather and Climate World Climate Radiation · Factors Affecting Air Pressure · Air Pressure and Winds · Relative Humidity · Types of Precipitation and Rainfall · Factors Affecting Rainfall · Major World Climates Hong Kong's Climate Seasons and Monsoon · Anticyclones · Cyclones · Fog China's Climate Overall Distribution · Latitude and Climate · Distance from the Sea · Relief and Climate Climatic Hazards Causes of Droughts · Impacts of Droughts · Solutions to Droughts · Causes of Sandstorms · Impacts of Sandstorms · Solutions to Sandstorms