Earth’s Atmosphere Chapter 15

Characteristics of the Atmosphere You should have all of your notes from 15.1 on this graphic organizer. Troposphere Stratosphere Mesosphere Thermosphere

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Auroras Northern and Southern Lights …WHY??? Nitrogen and Oxygen absorb energy from the sun Increase in temperature Electrically charge gas particles = ions The ions radiate energy as shimmering lights

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Atmospheric Heating Earth and the Atmosphere are warmed by energy from the sun! Heat moves from areas of warmth to areas of cold Three ways heat can be transferred: 1.Radiation 2.Conduction 3.Convection

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Radiation Transfers energy through infrared waves (sun or fire) Can move through EMPTY space No direct contact between heat source and an object. Example: bonfire warming your face Heat given off from a light bulb is also a form of radiation… Heat from a bonfire is an example of radiation…

Conduction Transfers heat through DIRECT CONTACT of particles (solid to solid) Example: bare feet on hot pavement A spoon heating up in a pot of soup! The pan gets HOT because it is touching the HOT burner on the stove!

Convection Transfer of heat through the movement of FLUIDS and GASES Example: soup heating inside a pot Movement is created by differences in DENSITY –Hot things = less dense = rise to the top –Cold things = more dense = fall to the bottom

Convection Example: Lava Lamp Hot! = less dense = rise to the top Cools off! = more dense = fall to the bottom

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Energy in the Atmosphere Comes from the sun!

Electromagnetic Waves Electromagnetic waves are energy from the sun that can travel through space Remember…. The transfer of energy by electromagnetic waves is called RADIATION.

Electromagnetic Spectrum The electromagnetic spectrum organizes the radiation from the sun from the longest wavelength to the shortest wavelength.

The Greenhouse Effect Earth’s atmosphere gases act as a “blanket” and hold in the heat from the infrared radiation. The greenhouse effect helps Earth maintain a comfortable livable temperature, even at night.

Heat Transfer (Review!!) 1.Radiation – Heat that you feel from a heat source. EX: sun or fire (infrared radiation) 2.Conduction – Direct transfer of heat from one object touching another object 3.Convection – Transfer of heat by the movement of a fluid or air (convection current) Radiation, conduction, and convection work together to heat the troposphere.

Heat Transfer (Review examples!!) AIR COOLS OFF (Drops back Down)

Which type of heat transfer? 1.Your feet get hot when walking barefoot across hot pavement. 2.You can feel the heat from the hot iron without touching it. 3.In winter, the second floor of your house is warmer than the first floor. 4.You are lying on the beach and the sun makes your skin tingle. 5.You burn your finger when you accidentally touch the hot stove.

Which type of heat transfer? 1.Your feet get hot when walking barefoot across hot pavement. Conduction 2.You can feel the heat from the hot iron without touching it. Radiation 3.In winter, the second floor of your house is warmer than the first floor. Convection 4.You are lying on the beach and the sun makes your skin tingle. Radiation 5.You burn your finger when you accidentally touch the hot stove. Conduction

Air in the atmosphere acts as a fluid (water vapor). The sun's radiation strikes the ground = warming the rocks/ground. As the ground’s temperature rises due to conduction, heat energy is released into the atmosphere, forming a “bubble” of air which is warmer than the surrounding air. This “bubble” of air rises into the atmosphere. As it rises, the air in the “bubble” cools and becomes more dense. The movement of the air creates wind. Convection currents are responsible for many weather patterns in the troposphere. Hot Air Rises… But how does the ground get hotter??? … It is farther from the sun!

ConvectionCurrents!

Winds 15.3

What causes winds? Differences in air pressureDifferences in air pressure More of a difference in pressure = faster windsMore of a difference in pressure = faster winds Lots of difference

Air Equator Air Poles You know… –Warm air rises = less dense –Cool air sinks = more dense Now understand…Now understand… –Warm air = less dense = low pressure –Cool air = more dense = high pressure

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Global Winds Created by unequal heating of Earth’s surface.Created by unequal heating of Earth’s surface.

Global Winds… cont… The movement of air between the equator and the poles produces global winds.The movement of air between the equator and the poles produces global winds. Coriolis effect produces patterns of air circulation called global winds.Coriolis effect produces patterns of air circulation called global winds.

Global Wind Belts Major global wind systems:Major global wind systems: Polar easterlies, westerlies, and trade winds.Polar easterlies, westerlies, and trade winds.

Doldrums Where the trade winds meet around the equatorWhere the trade winds meet around the equator Very little wind because the warm air rising = low pressureVery little wind because the warm air rising = low pressure

Horse Latitudes High pressure areas… 30 0 N and 30 0 SHigh pressure areas… 30 0 N and 30 0 S Very week windsVery week winds

Jet Streams Bands of high speed windsBands of high speed winds Upper troposphere and lower stratosphereUpper troposphere and lower stratosphere Blow from west to east at speeds of km/hr.Blow from west to east at speeds of km/hr. Help airplanes save fuel and time when traveling east.Help airplanes save fuel and time when traveling east.

Local Winds Have you ever flown a kite at the beach on a hot summer day? Even if there is no wind inland, there may be a cool breeze blowing in from the water toward the beach. This breeze is an example of local winds! Local winds are winds that blow over short distances.Local winds are winds that blow over short distances. They are caused by unequal heating of Earth’s surface within a small area.They are caused by unequal heating of Earth’s surface within a small area. Types:Types: –sea breezes and land breezes –Mountain breeze and valley breeze

Sea Breeze (Morning) Land heats up faster than water. Hot air over land rises (Low Pressure), cool air over water falls (High Pressure). Winds move from the water (High Pressure) to the land (Low Pressure).

Land Breeze (Evening) Land cools off faster than water. Cool air over land falls (High Pressure), warm air over water rises (Low Pressure). Winds move from the land (High Pressure) to the water (Low Pressure).

Valley Breeze (Day) During the day the sun warms the air slopes, creating a valley breeze… at nightfall, the air along the mountain slopes cools…

Mountain Breeze (Night) This cool air moves down the slopes into the valley, producing a mountain breeze!

Measuring Wind Winds are described by their direction and speed.Winds are described by their direction and speed. Wind direction is determined with a wind vane – points in the direction the wind is moving!Wind direction is determined with a wind vane – points in the direction the wind is moving! Wind speed is measured with an anemometer.Wind speed is measured with an anemometer. The increased cooling that a wind can cause is called the wind chill factor.The increased cooling that a wind can cause is called the wind chill factor. Anemometer – The cups catch the wind, turning faster when the wind blows faster. Wind Vane