H Geography - Physical Unit - Atmosphere - GHB

Global heat budget

• Of the 100% of radiation received from the sun, only approximately 46% reaches the earth’s surface. The other 54% is lost through a combination of reflection and absorption in the atmosphere.

• Heat can also be lost through contact with gas and dust in the air. This accounts for approximately 8% of the energy lost. Energy can also be scattered by the clouds, this accounts for 17% lost.

• Albedo effect takes place on land where dark rainforests absorb more radiation. Albedo effect also takes place on white polar ice. This accounts for approximately 6% of the heat loss.

• Insolation can also be lost through absorption. Water vapours and gases account for 19% of the loss. Clouds also account for 4% of the heat energy being absorbed.

Point 1 of the Global Heat Budget

• Of the 100% of radiation received from the sun, only approximately 46% reaches the earth’s surface. The other 54% is lost through a combination of reflection and absorption in the atmosphere.

Point 2 of the Global Heat Budget

• Heat can also be lost through contact with gas and dust in the air. This accounts for approximately 8% of the energy lost. Energy can also be scattered by the clouds, this accounts for 17% lost.

Point 3 of the Global Heat Budget

• Albedo effect takes place on land where dark rainforests absorb more radiation. Albedo effect also takes place on white polar ice, this reflects radiation. This accounts for approximately 6% of the heat loss.

Point 4 of the Global Heat Budget

• Insolation can also be lost through absorption. Water vapours and gases account for 19% of the loss. Clouds also account for 4% of the heat energy being absorbed.

How many reasons are there for an imbalance in the heat budget?

There are four reasons for an imbalance in the heat budget

What are reasons for an imbalance in the heat budget

The reasons for an imbalance in the heat budget are;

• Depth of atmosphere

• Albedo effect

• Angle of rays

• Tilt

Depth of atmosphere

• Rays have less atmosphere to pass through at the tropics, so less energy is lost through absorption and reflection

Albedo effect

• Albedo is the reflectiveness of the land surface, darker forest surfaces at the tropics have a lower albedo so absorb more energy in contrast with lighter ice covered areas at the poles

Angle of rays

• Due to the curvature of the Earth, in the tropics the sun’s rays are concentrated on a much smaller area, resulting in more intense heating

Tilt

• Due to the tilt of the Earth, limited insolation is received at the Poles in winter, whereas tropical areas receive insolation all year round.