WEATHER AND CLIMATE

Topic 2: RELATIVE

HUMIDITY AND RAINFALL

B. How is rain formed?

C. Is all rain a result of a same formation process?

- Rain is a form of precipitation consisting of water droplets and is convectional or orographic.

 

A. Define relative humidity and explain the difference in RH in different locations

D. Explain the formation of convectional and orographic rainfall

Topic 2. Relative humidity and RainfallEssential Questions

Definitions Learning outcomes

Sling psychrometer Text pg 172

• Instrument to measure Relative humidity

• Consist of wet and dry bulb thermometer

- Ratio between actual amount of water vapour and the maximum amount of water vapour that the air could hold

2A ) Define: Relative humidity

- Varies with temperature- Warm air can hold more water vapour

than cool air- Relative humidity decreases as

temperature increases

Relative humidity

SATURATION- Relative humidity at 100% = air

holds the maximum amount of water vapour

DEW POINT - Temperature at which

saturation occurs- Results in condensation (water

vapour changes to liquid form by cooling)

Relative humidity

PRECIPITATION Water in any form that falls from atmosphere to surface of the earth through CONDENSATION

2 rain types: Convectional Relief

2B) How is rain formed?

RAIN GUAGE Pg 173

Suitable location: Open area and stable ground

RAINFALL MEASUREMENT

GLASS BOTTLE

COPPERCYLINDER

OUTERCASING

FUNNEL

- Explain the process - Draw and label the diagrams

2D. Explain the formation of convectional and orographic

rainfall

TEXT PAGE 81

Convectional Rain

When earth surface is intensively heated eg tropics

Usually with lightning and thunder Short duration but intense rainfall

Relief rain

Occurs when moist air passes over the sea and arrives at the coast

1. Define relative humidity [1]

2. Explain the formation of convectional and orographic rainfall using diagrams [4]

Homework 2