What is Energy? Energy – the ability to do work Everything that is done in the universe requires the use or transfer of energy. Most of the surface processes on Earth are powered by energy from the Sun.

17.2 Heating the Atmosphere Energy Transfer as Heat 17.2 Heating the Atmosphere  Heat is the energy transferred from one object to another because of a difference in the objects’ temperature.  Temperature is a measure of the average kinetic energy of the individual atoms or molecules in a substance.

17.2 Heating the Atmosphere Energy Transfer as Heat 17.2 Heating the Atmosphere  Electromagnetic Waves • The sun emits light and heat as well as the ultraviolet rays that cause a suntan. These forms of energy are only part of a large array of energy emitted by the sun, called the electromagnetic spectrum.

Electromagnetic Radiation(Energy from the sun)

Electromagnetic Radiation (Energy from the Sun)

Visible Light Consists of an Array of Colors Makes no sense without caption in book

What makes an object hot? Heat: form of energy associated with the motion of atoms or molecules Heat transfer – the movement of thermal energy due to a temperature difference(from a warmer object to a cooler object) When an object is heated, the particles that make up the object move faster. Heat transfer stops when both objects reach the same temperature.

Thermal Energy Transfer Thermal energy can be transferred by 3 processes: Conduction Convection Radiation

Types of Heat Transfer Conduction – heat movement within an object or between objects that are touching. Transfer of energy by touch Not an effective transfer in a gas. Primarily solids

Conduction When you heat a metal strip at one end, the heat travels to the other end. As you heat the metal, the particles vibrate, these vibrations make the adjacent particles vibrate, and so on and so on, the vibrations are passed along the metal and so is the heat. We call this? Conduction

Types of Heat Transfer Convection– heat transfer by the movement(circulation) in fluids. Caused by density Hot fluid rises, cool fluid falls Examples: air in a heating system Generates sea breezes, land breezes, and surface winds Fluids are liquids or gases.

Water movement Cools at the surface Convection current Hot water rises Cooler water sinks

Air Currents

Why is it windy at the seaside?

Sea Breeze Land Breeze Sea breeze: During a hot day, the land is warmer than the sea. Air above the land is heated and rises up; it is then replaced by cooler air from the sea Occurs during the day wind blowing from the ocean towards land Land breeze: During the night, the sea is warmer than the land because the land loses its heat much faster than the sea. Air above the sea is warmer than that above the land so it rises up to be replaced by that air above the land. Occurs at night blows from the land to the water

Sea Breeze Land Breeze

Heat cells in mantle/asthenosphere Rising heat cells - plates separate Heat cells in mantle/asthenosphere Rising heat cells - plates separate Sinking heat cells - plates pulled down into mantle

Types of Heat Transfer Radiation – the movement of electromagnetic radiation (energy) through space No direct contact between heat source and an object All objects radiate heat: hotter objects radiate more The hotter the object, the shorter the wavelength Radiation can be absorbed or reflected Examples: --Heat felt from a campfire --radiation from the sun warms Earth --energy from the sun’s core heats outer surface of the sun Electromagnetic Waves Liquids solids and gases Higher temp = more energy given off Ex: sunlight, campfire, x-rays

17.2 Heating the Atmosphere What Happens to Solar Radiation? 17.2 Heating the Atmosphere  Reflection and Scattering • Reflection occurs when light bounces off an object. Reflection radiation has the same intensity as incident radiation. • Scattering produces a larger number of weaker rays that travel in different directions.

17.2 Heating the Atmosphere What Happens to Solar Radiation? 17.2 Heating the Atmosphere  Absorption • About 50 percent of the solar energy that strikes the top of the atmosphere reaches Earth’s surface and is absorbed. • The greenhouse effect is the heating of Earth’s surface and atmosphere from solar radiation being absorbed and emitted by the atmosphere, mainly by water vapor and carbon dioxide.

Summary

Summary

Summary

17.3 Temperature Controls Why Temperatures Vary  Factors other than latitude that exert a strong influence on temperature include heating of land and water, altitude, geographic position, cloud cover, and ocean currents.

17.3 Temperature Controls Why Temperatures Vary  Land and Water • Land heats more rapidly and to higher temperatures than water. Land also cools more rapidly and to lower temperatures than water.  Geographic Position The geographic setting can greatly influence temperatures experienced at a specific location

17.3 Temperature Controls Why Temperatures Vary  Altitude • The altitude can greatly influence temperatures experienced at a specific location.  Cloud Cover and Albedo • Albedo is the fraction of total radiation that is reflected by any surface. Many clouds have a high albedo and therefore reflect back to space a significant portion of the sunlight that strikes them.

Clouds Reflect and Absorb Radiation Makes no sense without caption in book

17.3 Temperature Controls World Distribution of Temperature  Isotherms are lines on a weather map that connect points where the temperature is the same. • Isotherms generally trend east and west and show a decrease in temperatures from the tropics toward the poles.