Chapter 2: Weather Factors Section 1: Energy in the Atmosphere

Heat is a major factor in weather Heat is a major factor in weather. The movement of heat in the atmosphere causes temperatures to change, winds to blow and rain to fall.

Transfer of energy by electromagnetic waves is called radiation Energy from the Sun Nearly all energy in Earth’s atmosphere comes from the sun. This energy travels to Earth as electromagnetic waves, which is a form of energy that can travel through space Transfer of energy by electromagnetic waves is called radiation Most of the energy from the sun reaches Earth in the form of visible light and infrared radiation, and a small amount of ultraviolet radiation

Infrared Radiation: form of energy with wavelengths that are longer than red light   Ultraviolet Radiation: form of energy with wavelengths that are shorter than violet light

THE ELECTROMAGNETIC SPECTRUM

Energy in the atmosphere Some of the energy from the sun is absorbed within the atmosphere(through water vapor, CO2, ozone layer, clouds, dust and other gases) Some of the energy from the sun is reflected (clouds, dust particles and molecules of gases)

Scattering Scattering: reflection of light in all directions Gas molecules scatter short wave-lengths of visible light (blue and violet) making the sky appear blue during the day. When the sun is rising or setting, light passes through a greater thickness of the atmosphere, more blue is removed by scattering, leaving mostly red light to reach your eyes.

When Earth’s surface is heated, it radiates some of the energy back into the atmosphere as infrared radiation. Greenhouse effect: process by which gases hold heat in the air The two main greenhouse gases are Carbon Dioxide and Water Vapor