The Earth’s AtmosphereThe Earth’s Atmosphere

Layers of AirLayers of Air

• There are 4 basic layers of air:There are 4 basic layers of air:

• 1. Troposphere1. Troposphere

• 2. Stratosphere2. Stratosphere

• 3. Mesosphere3. Mesosphere

• 4. Thermosphere4. Thermosphere

-100 -80 -60 -40 -20 0 20 40 60 80 100 120

Thermosphere

Mesosphere

Stratosphere

Ozone

Troposphere

-120

Temperatures in degrees Celsius

20 Miles

40 Miles

60 Miles

80 Miles

100 Miles

TroposphereTroposphere

• The The _______________ is where all is where all weather takes place; it is the weather takes place; it is the region of rising and falling packets region of rising and falling packets of air. of air.

• The air pressure at the top of the The air pressure at the top of the troposphere is only 10% of that at troposphere is only 10% of that at sea level (0.1 atmospheres). sea level (0.1 atmospheres).

TroposphereTroposphere

• The troposphere starts at the Earth's The troposphere starts at the Earth's _______________ and extends 8 to 14.5 and extends 8 to 14.5 kilometers high (5 to 9 miles). kilometers high (5 to 9 miles).

• This part of the atmosphere is the This part of the atmosphere is the most dense. most dense.

• As you climb higher in this layer, the As you climb higher in this layer, the temperature drops from about 17 to -temperature drops from about 17 to -52 degrees Celsius. 52 degrees Celsius.

StratosphereStratosphere

• The The _______________ starts just above the starts just above the troposphere and extends to 50 kilometers troposphere and extends to 50 kilometers (31 miles) high. (31 miles) high.

• Above the troposphere is the Above the troposphere is the stratospherestratosphere, , where air flow is mostly where air flow is mostly _______________. .

• The thin ozone layer in the upper The thin ozone layer in the upper stratosphere has a high concentration of stratosphere has a high concentration of _______________, a particularly reactive , a particularly reactive form of oxygen.form of oxygen.

StratosphereStratosphere

• The thin ozone layer in the upper The thin ozone layer in the upper stratosphere has a high concentration stratosphere has a high concentration of ozone, a particularly reactive form of of ozone, a particularly reactive form of _______________..

• This layer is primarily responsible for This layer is primarily responsible for absorbing the absorbing the _______________from the from the Sun. Sun.

• There is considerable recent concern There is considerable recent concern that manmade fluorocarbon that manmade fluorocarbon compounds may be depleting the compounds may be depleting the ozone layer ozone layer

MesosphereMesosphere

• The The _______________ starts just above starts just above the stratosphere and extends to 85 the stratosphere and extends to 85 kilometers (53 miles) high .kilometers (53 miles) high .

• In this region, the temperatures In this region, the temperatures again fall as low as -93 degrees again fall as low as -93 degrees Celsius as you increase in altitude. Celsius as you increase in altitude.

Thermosphere (Ionosphere)Thermosphere (Ionosphere)

• The The _______________ is very thin, but it is very thin, but it is where aurora take place, and is is where aurora take place, and is also responsible for absorbing the also responsible for absorbing the most energetic most energetic _______________ from from the Sun, and for reflecting radio the Sun, and for reflecting radio waves, thereby making long-distance waves, thereby making long-distance radio communication possible. radio communication possible.

ThermosphereThermosphere

• The thermosphere starts just above The thermosphere starts just above the mesosphere and extends to 600 the mesosphere and extends to 600 kilometers (372 miles) high. kilometers (372 miles) high.

• Temperatures in this region can go Temperatures in this region can go as high as 1,727 degrees Celsius. as high as 1,727 degrees Celsius. Chemical reactions occur much Chemical reactions occur much faster here than on the surface of faster here than on the surface of the Earth. the Earth.

• This layer is known as the This layer is known as the ______________________________. .

Composition of the Composition of the AtmosphereAtmosphere

• The atmosphere is primarily The atmosphere is primarily composed of composed of – _______________ - 78% - 78%– _______________ - 21% - 21%– _______________ - 1%. - 1%.

WindsWinds

•Jet StreamJet Stream

• Once air begins moving, the Earth's Once air begins moving, the Earth's rotation causes it to follow a curved rotation causes it to follow a curved path; this is referred to as the path; this is referred to as the _______________..

Jet StreamJet Stream

• The term "jet stream" is often used The term "jet stream" is often used to refer to the to refer to the ________________________ high in the high in the atmosphere - above about 20,000 atmosphere - above about 20,000 feet .feet .

• These winds help determine the These winds help determine the locations of areas of high and low air locations of areas of high and low air pressure at the Earth's surface. pressure at the Earth's surface.

• A jet stream is "a relatively narrow A jet stream is "a relatively narrow river of very strong river of very strong _______________ winds. winds.

• Jet streams form along the upper air Jet streams form along the upper air boundaries of large masses of warm boundaries of large masses of warm and cold air. and cold air.

• During major cold outbreaks over the During major cold outbreaks over the USA, the jet stream often dives south - USA, the jet stream often dives south - staying above the warm-cold staying above the warm-cold boundary - sometimes moving well boundary - sometimes moving well over the Gulf of Mexico. over the Gulf of Mexico.

• During unusually mild winter weather During unusually mild winter weather and during the summer, the jet stream and during the summer, the jet stream retreats northward into Canada.retreats northward into Canada.

Jet Stream Patterns

Jet Stream Patterns

Jet Stream Patterns

CloudsClouds

•CirrusCirrus

•StratusStratus

•CumulusCumulus

•Nimbus - prefixNimbus - prefix

Cirrus CloudsCirrus Clouds• Cirrus clouds are thin, wispy clouds Cirrus clouds are thin, wispy clouds

that usually form above 18,000 feet. that usually form above 18,000 feet.

• Cirrus clouds generally move from Cirrus clouds generally move from _______________ to to _______________ across the sky and usually "point" to across the sky and usually "point" to fair weather. fair weather.

• Cirrus clouds are thin because they Cirrus clouds are thin because they form in the higher levels of the form in the higher levels of the atmosphere where little water vapor atmosphere where little water vapor is present. is present.

Cirrus Clouds

Stratus Clouds - Fog

• Fog forms when the air cools to a Fog forms when the air cools to a point at which water vapor in it point at which water vapor in it begins to condense into tiny water begins to condense into tiny water droplets. droplets.

• The temperature at which water The temperature at which water vapor will begin condensing from the vapor will begin condensing from the air at any particular time is called the air at any particular time is called the ""_______________." ."

• Stratus clouds are uniform gray clouds Stratus clouds are uniform gray clouds that usually cover the entire sky. that usually cover the entire sky.

• Stratus clouds look like a layer of fog Stratus clouds look like a layer of fog that never reaches the ground. that never reaches the ground.

• Precipitation rarely falls from true Precipitation rarely falls from true stratus clouds, but light mist and stratus clouds, but light mist and drizzle can sometimes accompany drizzle can sometimes accompany stratus clouds. stratus clouds.

Stratus Clouds

Cumulus Clouds

Cumulus Clouds

• Cumulus clouds form as water vapor Cumulus clouds form as water vapor condenses in strong, upward air condenses in strong, upward air currents above the earth's surface. currents above the earth's surface.

• These clouds usually have These clouds usually have _______________ and and _______________..

• Most cumulus clouds form below Most cumulus clouds form below 6,000 feet and are relatively thin and 6,000 feet and are relatively thin and associated with fair weather. associated with fair weather.

• When the atmosphere becomes When the atmosphere becomes unstable, and very strong, upward air unstable, and very strong, upward air currents form, cumulus clouds can currents form, cumulus clouds can grow into cumulus congestus, or grow into cumulus congestus, or _______________. .

• If the atmosphere is unstable If the atmosphere is unstable enough, cumulonimbus clouds, enough, cumulonimbus clouds, better known as thunderstorms, better known as thunderstorms, form. form.

• Cumulus congestus and Cumulus congestus and cumulonimbus clouds can tower from cumulonimbus clouds can tower from below 6,000 feet to greater than below 6,000 feet to greater than 50,000 feet. 50,000 feet.

Cumulus Clouds

Other Cloud TypesOther Cloud Types

ContrailsContrails

Mammatus CloudsMammatus Clouds

Mammatus CloudsMammatus Clouds

• These pouch-like clouds often form These pouch-like clouds often form underneath a thunderstorm where underneath a thunderstorm where cooler air sinks into warmer below cooler air sinks into warmer below the storm cloud.the storm cloud.

•_______________ clouds look clouds look threatening, but actually signal the threatening, but actually signal the weakening of a thunderstorm. weakening of a thunderstorm.

PrecipitationPrecipitation

•RainRain

•SnowSnow

•SleetSleet

•Freezing RainFreezing Rain

•HailHail

Rain

Snow

Sleet

Freezing Rain

Hail

Hail

Hail

WeatherWeather

• ThunderstormsThunderstorms– Cumulus clouds, strong winds, heavy Cumulus clouds, strong winds, heavy

rain, lightning, and thunder.rain, lightning, and thunder.– Single CellSingle Cell– Multi CellMulti Cell– SupercellSupercell

Single CellSingle Cell

Single CellSingle Cell

• Severe weather is limited to brief, Severe weather is limited to brief, isolated -isolated -– downbursts, small hail, heavy rain, and downbursts, small hail, heavy rain, and

weak tornadoesweak tornadoes– low degree of predictability of severe low degree of predictability of severe

eventsevents– low to moderate danger to publiclow to moderate danger to public– moderate to high danger to aviation.moderate to high danger to aviation.

MulticellMulticell

MulticellMulticell

SupercellSupercell

SupercellSupercell

LightningLightning•_______________ - electrical discharge - electrical discharge

that travels between 2 oppositely that travels between 2 oppositely charged surfaces (friction occurs charged surfaces (friction occurs between the raindrops and ice between the raindrops and ice crystals as they are being pushed up crystals as they are being pushed up and down in the clouds).and down in the clouds).

LightningLightning• The upper portion of the clouds become The upper portion of the clouds become

positively charged and the lower portion positively charged and the lower portion becomes negatively charged.becomes negatively charged.

• Eventually the charge in the lower portion Eventually the charge in the lower portion of the clouds becomes great enough to of the clouds becomes great enough to pull away from the ground, making it pull away from the ground, making it positively charged.positively charged.

• Difference is great enough, the electrical is Difference is great enough, the electrical is discharged from the cloud to the ground.discharged from the cloud to the ground.

LightningLightning

• Lightning follows the shortest path - Lightning follows the shortest path - striking the tallest or highest object.striking the tallest or highest object.

• We hear thunder because lightning heats We hear thunder because lightning heats the air to more than 43,000 degrees, the air to more than 43,000 degrees, causing the air to quickly expand. The air causing the air to quickly expand. The air then quickly cools after the flash, which then quickly cools after the flash, which causes it contract. causes it contract.

• This quick expansion and contraction of air This quick expansion and contraction of air around the lightning starts air molecules around the lightning starts air molecules moving back and forth, making sound moving back and forth, making sound waves, which we hear as waves, which we hear as _______________..

TornadoTornado• Intense storm with high winds that Intense storm with high winds that

circle a small center of extremely low circle a small center of extremely low pressure.pressure.

• Form along cold fronts.Form along cold fronts.

• Spin Spin _______________..

•_______________ - tornado over a body - tornado over a body of water like a lake.of water like a lake.

TornadoTornado

TornadoTornado

TornadoTornado• Dr. Theodore FujitaDr. Theodore Fujita

– Well known researcher.Well known researcher.– Came up with the Fujita scale - F1, F2, Came up with the Fujita scale - F1, F2,

F3, F4, F5F3, F4, F5– Scale is based on the wind speed of a Scale is based on the wind speed of a

tornado.tornado.

HurricaneHurricane• Cyclonic storms that develops over Cyclonic storms that develops over

warm ocean water. (Get their energy warm ocean water. (Get their energy from the water)from the water)

• Western Pacific Ocean - Western Pacific Ocean - ______________

• Indian Ocean - Indian Ocean - _______________

• Named after females until the late Named after females until the late 70’s. 70’s.

HurricanesHurricanes

The seven main characteristics The seven main characteristics that define a hurricane, are:that define a hurricane, are:

• Hurricanes have no Hurricanes have no _______________. . • Hurricane winds weaken with height Hurricane winds weaken with height • The centers of hurricanes are warmer The centers of hurricanes are warmer

than their surroundings than their surroundings • Hurricanes and tropical systems form Hurricanes and tropical systems form

under weak high-altitude winds. under weak high-altitude winds. • Air sinks at the center of a hurricane Air sinks at the center of a hurricane • Hurricanes' main energy source is the Hurricanes' main energy source is the

latent heat of condensation latent heat of condensation • Hurricanes weaken rapidly over land Hurricanes weaken rapidly over land

Tropical systems are classified into four Tropical systems are classified into four categories according to its degree of categories according to its degree of organization and maximum sustained organization and maximum sustained wind speed.wind speed.

•_______________, tropical wave:, tropical wave: Unorganized Unorganized mass of thunderstorms, very little, if any, mass of thunderstorms, very little, if any, organized wind circulation.organized wind circulation.

•_______________:: Has evidence of closed wind Has evidence of closed wind circulation around a center with sustained circulation around a center with sustained winds from 20-34 knots (23-39 mph).winds from 20-34 knots (23-39 mph).

• _______________:: Maximum sustained winds are Maximum sustained winds are from 35-64 knots (40-74 mph). The storm is from 35-64 knots (40-74 mph). The storm is named once it reaches tropical storm strength. named once it reaches tropical storm strength.

• _______________:: Maximum sustained winds Maximum sustained winds exceed 64 knots (74 mph). exceed 64 knots (74 mph).