Climate Earth’s Energy Budget

The Flow of Energy Solar power drives Earth’s climate. Energy from sun: heats surface and warms the atmosphere Provides energy for photosynthesis Causes evaporation Drives weather and water cycles Powers ocean currents

Earth’s atmosphere Looking up at the sky from the ground, the atmosphere seems to go on forever. Realistically, however, it is extremely thin compared to the diameter of the earth. Two important layer to Earth’s processes are: Troposphere Stratosphere

Radiation The transfer of energy by electromagnetic waves. Reaches Earth’s surface in two forms Visible light Infrared light Two different things can happen to energy that has passed through Earth’s outer atmospheric layers: Absorption Reflection Once energy has been absorbed by the Earth system it is transformed and transferred, and can be radiated back into space, eventually reaching equilibrium.

Thermal energy The transfer of energy from one region to another is called thermal energy or heat. It can happen by three processes: Radiation Conduction Convection Thermal Energy or heat always moves from things that are warmer (have more energy), to things that are cooler (have less energy).

Overview of earth’s energy pathways SUN OUTER SPACE Atmosphere Earth emitted is high-energy, short-wave radiation in the form of visible and ultraviolet light and reaches the top of the Earth’s atmosphere 1 Some reflects off of light colored surfaces such as snow, ice and sand and returns to space, a small amount is absorbed by atmospheric dust and water vapor and warms the atmosphere small amount of radiation is absorbed by dust and water vapor and warms the atmosphere. Some is reflected back into space by clouds or tiny particles in atmosphere. 3 2 Most solar energy that reaches Earth is absorbed by land and oceans and warms Earth

The Greenhouse effect Energy coming from the sun is HIGH FREQUENCY, short wavelength radiation and can easily penetrate earth’s atmosphere. Travels 93 million miles to Earth in 8 seconds. Energy radiated from Earth’s surface is low frequency, long wavelength radiation. As it reflects off of the earth’s surface, it is absorbed by greenhouse gas molecules in the atmosphere. Without greenhouse gases, the low energy long-wave radiation would quickly escape into space and Earth would be FROZEN.

Checking In: Sunlight provides energy in WHAT FORM? Why is it called an “energy balance”? Describe 3 places where radiation is absorbed. List surfaces that reflect solar radiation. Describe 3 ways in which radiation gets back OUT of the system?

Checking In: Sunlight provides energy in WHAT FORM? A. radiation Why is it called an “energy balance”? A. Equal amounts enter and exit the system. List 3 places where radiation is absorbed. A. Water vapor, clouds, land List surfaces that reflect solar radiation. A. Water and clouds (also snow, glaciers) Describe 3 ways in which radiation gets back OUT of the system? Latent heat tranforms radiation into kinetic energy of water molecules (liquid to gas=energy absorbed) Temperature change occurs when solar radiation is absorbed by the surface. Air heated by surfaces that absorb solar radiation trigger convection currents.