Climatic Variation

1. Climatic Variation Why climate is different in different locations

2. Latitude

3. Why does latitude make a difference? • The same amount of solar energy is spread across a greater area as you move away from the equator

4. Seasonal differences * The angle of incidence changes as the seasons change Summer = more direct sunlight (closer to 90°) + longer sunlight hours = more heating A lower angle of incidence also means the suns rays pass through more atmosphere before they reach the earth = more diffusion = less heat

6. The surface of the earth • Different types of surfaces reflect or absorb sunlight • The amount of reflectivity is known as ‘albedo’

7. Land vs Sea • Land heats and cools twice as much as water • - to raise the temp 1°C water needs twice as much heat as land! • The transparency of water allows it to distribute heat more readily • Land controlled climate (e.g. Russia) has wide ranges of temp. • Water (maritime) controlled climate (e.g. NZ) has a smaller temp. range

8. Land vs Sea II • Note the amount reflected from ice vs water. • Think – why does melting ice caps matter…?

9. The moisture system • This system is powered by the sun. The more solar energy – the more the capacity to hold water vapour in the atmosphere. • Humidity = amount of water vapour in the air; 100 = saturated, 10% = dry • Air rises » As it rises it cools 0.6°C per 100m » it condenses into droplets and forms clouds » As clouds rise droplets increase and rain falls • There are three types of rainfall…

12. Convection rainfall

13. Frontal (cyclonic) rainfall

14. So how about the Waitakere Ranges? • Summer – high incidence angle (72-75°), wind predominantly from the West/North-West bringing hot moist air from the Tasman Sea. Occasionally large fronts of warm air come south and meet cooler air over North Island. Average temp =