ENERGY TRANSFER MECHANISMS IN THE ATMOSPHERE

Energy is everywhere. Energy is the ability or capacity to do work on some form of matter. By doing work on something we give it energy, which it can in turn use to do work on other things. Energy exists in many forms, it cannot be created or destroyed, it merely changes form.

Kinetic energy - also depends on its mass.

Potential energy, represents the potential to do work. In atmospheric science, gravitational potential energy.

Another example is radiant energy - the energy we get from the sun.

Heat is energy in the process of being transferred from one object to another because of the temperature difference between them. After heat is transferred it is stored as "internal energy" which is the total energy stored in the molecules.

How is energy transferred in the atmosphere? Before we do this lets discuss the concept of sensible heat, specific heat and latent heat.

Sensible heat - heat we feel and measure with a thermometer

Specific Heat - The amount of heat needed to raise the temperature of one gram of a substance 1C. Water has a much higher capacity for storing energy than other substances -e.g. sand or air. Water is therefore very important in determining a regions climate/weather.

Visible radiation has a wavelength less than one millionth of a meter - 100th of the diameter of a human hair - micron. Eyes are sensitive to radiation between 0.4 and 0.7 microns. (violet-red)The sun emits 44% of its energy in this region. UV rays wavelength between about .1 and .4 microns.

UV-C < .28

UV-B .28 - .32 microns

UV-A .32 - .4 microns

Most of the remaining energy is at wavelengths between .7 and 4 micron (near infrared).

All things no matter how small emit radiation. As the temperature is increased, more total radiation is emitted. The hotter the temperature; the greater the amount of energy at shorter wavelengths.

What happens when radiation interacts with an object?

Planet reflects 30% of the sun's energy back to space, 50% makes its way to the surface

Selective reflectors and absorbers: glass, snow. Atmospheric "Windows: - .5-.7 - solar 10-12 microns terrestrial window. Important in the greenhouse effect.