The Atmosphere Chapter 17.1 What is the atmosphere? A blanket of gases that surrounds Earth. Can these gases be seen? No Felt? Yes,,,as wind

Lesson Objectives Identify the major components of Earth’s atmosphere Explain how air pressure changes with altitude Explain how temperature changes with altitude Describe the layers of the atmosphere Explain how the processes of radiation, conduction and convection distribute energy in the atmosphere

What is Air? A mixture of gases and particles each with their own properties Nitrogen and Oxygen make up 99% of the volume of air Argon gas 0.93% CO2 0.039% Also contains: H2O vapor, ice, dust particles, hydrogen, salt and ozone

Structure of the Atmosphere The Atmosphere is made up of 5 different layers. Each layer is different in composition and temperature It is thickest near the surface of Earth and thins out with height until it eventually merges with space.

Layers of the Atmosphere- Troposphere Closest to Earth surface Contains most of the mass of the atmosphere Weather takes place Pollution collects There is a decrease in temperature as you travel up the Troposphere Lapse Rate The upper-limit of the Troposphere is called the Tropopause Densest layer Lapse Rate = temp decreases by about 6.5 degree C for every km of altitude Airplanes fly in this layer Almost all of the CO2, water vapor, clouds, and life occur here ~16 km above earth’s surface in tropics ~ 9 km at poles Troposphere means “Sphere of change” it is constantly changing

Layers of the Atmosphere- Stratosphere Located above the Tropopause Made up primarily of concentrated ozone Ozone absorbs ultraviolet radiation from the sun So…what do you think happens here in terms of temperature? The top of the Stratosphere is called the Stratopause Many jet aircrafts fly in this layer because it is very stable 99.9 % of the mass of Earth’s atmosphere is below the stratopause Extends up to 50 km Ozone is created here

Layers of the Atmosphere- Mesosphere Located above the Stratopause No ozone …so what happens to the temperature? Top of the Mesosphere is called the …… Meteors burn up in this portion of the atmosphere Coldest part of the atmosphere -93degree C 50-100 km above earth’s surface

Layers of the Atmosphere- Thermosphere Contains only a minute portion of the atmosphere’s mass Air that does exist in this layer increases in temperature to more than 1000°C Ionosphere is with thermosphere Nitrogen and oxygen atoms absorb harmful solar energy…X-rays and gamma rays Causes the high temperatures Gas particles lose electrons and become ions Auroras- Northern and Southern Lights occur The molecules that make up the air are so sparse and widely spaced that despite the high temperature this layer would not seem warm to human passing though it The charged particles in the ionosphere reflect radio waves emitted from Earths’ surface….helping transmit radio signals around the world Layer between 100 km and 500 km above Earth’s surface

Layers of the Atmosphere- Exosphere Outermost layer of the atmosphere Lighter elements are found in this layer Above the Exosphere is outer space Hydrogen and Helium 500 km to 10000km above Earth’s surface There is no clear boundary between the atmosphere and space-just fewer and fewer molecules with increasing altitude Satellites orbit here without being slowed by friction

Solar Fundamentals The sun is the source of all of the energy in the atmosphere This energy is transferred to the Earth and throughout the atmosphere by convection, conduction and radiation

Heat Transfer Convection Conduction The transfer of energy by the flow of a heated substance Responsible for the vertical motions of air, which causes different types of weather Works based on density Conduction Transfer of energy that occurs when molecules collide Affects only a very thin atmospheric layer near Earth’s surface

Heat Transfer Radiation Transfer of energy through space by visible light, UV radiation and other forms of electromagnetic waves Earth’s surface absorbs the solar radiation and then radiates energy with longer wavelengths, which warm the atmosphere through convection and conduction