The Earth's energy budget

Most of the Earth's heat is derived from the sun

There are 4 factors which influence the amount of energy recieved by the Earth from the sun

• The rate of which energy reahes the Earth's surface from the sun 
• Energy is taken to be 1,388 watts per square meter 
• It varies slightly and affects longer term climate rather than short term weather

• The difference is about 150 million km but Earth's orbit is elliptical causing up to 6% variation in solar constant 

• The equator recieves more energy as solar radiation strikes the Earth head on 
• At 60 degrees N and S it approaches more oblique angle, giving twice the area to heat up and more atmosphere to pass through 

• The 23.5% tilt of the Earth means that regions near the poles recieve no insolation