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Air, Weather, and Climate

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Presentation on theme: "Air, Weather, and Climate"— Presentation transcript:

1 Air, Weather, and Climate

2 Earth’s Atmosphere Compared to the size of the Earth (12000 km), the atmosphere is a thin shell (120 km) Composed of: ~78% N2 gas 21% O2 gas 1% argon gas and other permanent gases

3 If the Earth is compared to this Orange…
the Earth’s atmosphere would be thinner than the layer of pesticide on this Orange’s surface

4 Layers of the Atmosphere
Troposphere Stratosphere Mesosphere Thermosphere Ionosphere Exosphere

5 Troposphere Closest to the earth’s surface Where we live
Weather occurs here very thin (averaging 11 km or 7 miles high) Densest layer Most of nitrogen, oxygen and water vapor here Temp decreases as altitude increases

6 Stratosphere Above the troposphere
extends to 50 kilometers (31 miles) high dry and less dense UV rays reach higher altitudes and warm them Ozone layer Ozone layer: made up of 3 oxygen atoms; absorbs UV-B and UV-C radiation

7 Mesosphere extends to 85 kilometers (53 miles) high
temperature decrease with altitude reaching °C at the top

8 Thermosphere extends to 600 kilometers (372 miles) high
temperatures go up as altitude increases due to absorption of solar radiation by oxygen molecules so few and far between that they collide rarely Farthest away from earth’s surface

9 Ionosphere Within the thermosphere
Contains ions when hit by solar energy begin to glow and produce light Aurora Borealis reflects many types of radio waves allowing them to bounce around the world Ions=charged gas molecules Glow: driven by magnetic forces: best places to see them is in the higher latitudes

10 Exosphere Top of the thermosphere and continues until it merges with interplanetary gases, or space (372 to 6200 miles)

11 Seasonal Changes Occurs due to earth’s axis being tilted
Creates opposite seasons Factor that determines global air circulation patterns

12 Seasons Seasons are short periods of climatic change.
Certain areas receive changing amounts of radiation throughout the year Due to tilt of earth’s axis

13 Earth’s Seasons Earth SUMMER (Northern Hemisphere)
North Pole Equator Earth South Pole WINTER (Southern Hemisphere)

14 Earth’s Seasons Continued….
Tilt of the Earth’s axis towards or away from the sun creates the seasons WINTER (Northern Hemisphere) North Pole South Pole Equator Earth SUMMER (Southern Hemisphere)

15 Weather Weather – daily temperature and moisture conditions in a place
driven by atmosphere atmospheric conditions over short time periods (hours or days) in small geographic areas produced by interacting air masses Types of weather Warm Front-warm air displaces cool air Cold Front-cooler air displaces warmer air Severe-hurricanes, thunderstorms, tornadoes

16 Weather Contribute to Weather Air temperature Air pressure Humidity
Cloud cover Precipitation Winds

17 Air Temperature As solar energy reaches the equator, regions heat up more than the poles. Warm air and water at the equator travel toward the poles while cold air and water at the poles travel toward the equator in an attempt to equalize the temperature Constant struggle = changing weather


19 Air Pressure Caused by the weight of air pressing down on the Earth
High pressure-cool, dense air that descends towards surface of earth Fair weather Low pressure-less dense warm air goes toward the center of a low pressure air mass Produces cloudy and stormy weather Air pressure changes with weather

20 As air rises higher in the atmosphere, pressure decreases; lower pressure allows the rising air to expand in volume and this lowers the temp When air sinks towards the earth the pressure increases; higher pressure forces the air to decrease in volume and raises the temp of the air

21 Humidity and Cloud Cover
Relative humidity-amount of water vapor in the air Cloud Cover clouds cool the planet by reflecting sunlight Albedo reduces the amount of heat that radiates into space

22 Winds Speed is determined by differences in pressure Coriolis effect
Deflection of objects moving in a straight path relative to the earth’s surface Proportional to the speed of the earth’s rotation at different latitudes as latitude increases and the speed of the earth’s rotation decreases, Coriolis effect increases

23 Winds cont. Hadley cells Solar energy warms humid air in tropics
Warm air rises, cools, condenses and precipitates Dry air sinks and is warmed Hot dry air causes deserts



26 Convection Currents

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