2 Weather and the Atmosphere Weather is the condition of the Earth’s atmosphere at a particular time and place.Earth’s atmosphere is the envelope of gases that surround the planet.The atmosphere is made of many types of gases as well as dust, salt, and other chemicals that are too small to see.
3 Gases in the Air Nitrogen – N2 – The most abundant type of gas – 78% Oxygen – O2 – Used by plants and animals, needed for burning – 21%Carbon Dioxide – CO2 – Used by plants to make food, is released when coal/gas are burned - < 1%Water Vapor – H2O – Can vary greatly from place to place and time to time - < 1%Other – Argon, Neon, Helium, Methane, Krypton, Hydrogen
6 TroposphereMeans “turning” or “changing” because of its variable conditionsGoes from 0 km to 12 km above sea levelWeather occurs here including rain, snow, storms, and most cloudsThe higher you go, the lower the temperatureAt the top, it is about -60°C and water forms thin, feathery clouds of ice
7 Stratosphere Means “layer” or “spread out” Goes from 12 km to 50 km above sea levelContains the ozone layer which is made from O3 and protects us from ultraviolet raysThe higher you go the warmer it gets because the ozone layer absorbs energy, heating up the air
8 Mesosphere Means “middle” Goes from 50 to 80 km above sea level Protects the Earth from being hit by most meteoroidsWhat we see as shooting stars or meteors are trails of hot, glowing gases of meteoroids burning upTemperatures decrease to -90°C
9 Thermosphere Means “heat” Goes above 80 km and has no definite outer limitBlends gradually with outer spaceGets very hot (1,800°C) because the sun hits it firstHas two layers: the ionosphere and exosphereThe ionosphere goes till 400 km and is where we see the Northern Lights