Climate

Where is solar insolation the most direct?

The Equator

How is heat redistributed globally? (2)

• Pressure differences

• Ocean currents

Explain what is meant by pressure differences (as simple as possible)

• Land absorbs sunlight - converts it to heat

• Heats air above - air expands, becomes lighter, and rises

• Which forms areas of low pressure

• Sea reflects some sunlight, some absorbs to 30m

• Takes sea longer to heat, and longer to cool

• Air remains cooler

• Forms areas of high pressure

• Differences in pressure cause air to move - high to low

• This creates wind - which travels straight

• Earth is always rotating

• Rotating earth - winds no longer straight

• This is the coriolis effect

Explain what is meant by ocean currents (as simple as possible)

• In the north Atlantic, cold and salty water is heavy

• This means it sinks

• Turns into convection current (drags surface water down)

• The current draws in warmer salty water from areas around the equator

• This also cools an sinks, then flows south to equator to be warmed again

For example

• Isles of Scilly (UK) - very warm

• St Johns (Canada) - freezing

• Different because of the gulf stream

How to draw and interpret climate graphs?

Drawing a graph

• draw a graph axis based on values given

• y-axis should be 12cm (1cm per month)

• plot rainfall as bars

• plot temperature data as points then join with a line

Interpreting temperature

• calculate mean (average) for the year

• find warmest and coolest and calculate difference = temperature range

• see how steep the graph is = trends

Interpreting rainfall

• calculate annual total

• find wettest and dryest

• see how they vary