Rainfall

How are clouds classified?

Clouds form when moist air rises and condenses into water or ice crystals. This takes between a few minutes and an hour.

Cloud formation

Clouds are classified using three criteria:

if they bring precipitation.

shape

altitude

Clouds are named according to their height, shape and whether

they bring precipitation.

nimbus

stratus

Heaped fluffy cloud

Brings rain

Mid-level cloud

Layered cloud

Cumulo

Alto

Cloud types

Rainfall is measured using a rain gauge.

RainfallRain is a type of precipitation.

Precipitation occurs when water vapour in the air cools and condenses into water droplets.

Snow, sleet, hail, dew and fog are also types of precipitation.

Rainfall is usually measured in millimetres (mm).

How is rainfall measured?

Can you recall how to draw and label the different parts of the rain gauge?

Where should the rain gauge be place?

• In an open area / field– So that nothing will

block the rain from being collected in the rain gauge.

Where should the rain gauge be place?

• A rain gauge should not be place near trees.– So that excess water collected from the leaves

will not drip into the rain gauge making reading inaccurate .

OR– The tree prevent water from being collected in

the rain gauge make the reading inaccurate.

Where should the rain gauge be place?

• A rain gauge should not be place near buildings.– So that excess water from the rooftop will not

drip into the rain gauge making reading inaccurate .

– The building could also radiate heat causing the water collected to evaporate.

Where should the rain gauge be place?

• It should be partially buried in the ground– to prevent it from being

topple.

Where should the rain gauge be place?

• It should be placed 30 cm above the ground– to prevent rain splash

entering the rain gauge making the reading inaccurate.

High tech weather instruments

Isohyets

• a line on a map connecting places having equal rainfall

Climograph

• It is a graph that shows the monthly precipitation and temperature conditions for a selected place.

• Precipitation is shown by the bar graph.

• A line graph shows temperature.

• What is the rainfall for the month of July?

• Which month experiences the highest temperature?

• What is the temperature range for the whole year?

• What is the average precipitation from May to July?