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17.1 Vocab Charts (Example)
Word Definition Picture
Weather the state of the atmosphere at a given time and
place
Weather = the state of the atmosphere at a given time and place (constantly changing)
- controlled by Earth’s motions & energy from the sun
Climate = the given weather conditions of an area over many years
- covers average rainfall, avg. temperature, avg. humidity, avg. wind direction, avg. air pressure etc…
Composition of the AtmosphereComposition of the Atmosphere
• Earth’s early atmosphere thought to be created by large volcanic eruptions of gas
• Oxygen was not present in the atmosphere until ~2.5 billion years ago
• Current atmosphere constantly exchanging gases with oceans and life on Earth
• Current composition of atmosphere:78% Nitrogen21% Oxygen0.93% Argon (inert gas)0.039% Carbon Dioxide
Composition cont…Composition cont…
Also present in atmosphere = water vapor, dust, ozone, and pollution–Water vapor makes up clouds &
precipitation
– Ozone (O3) is concentrated between 10 -50 km from surface
• Block harmful Ultraviolet (UV) rays
– Air pollution is mainly from car exhaust
Structure of AtmosphereStructure of Atmosphere
- There is no distinct boundary between the atmosphere and outer space, but it does thin as you increase in altitude
The atmosphere is divided into 4 layers based on temperature:
1. Troposphere = temperature decreases as you increase altitude
- Extends from surface to ~12 km- All weather occurs here
2. Stratosphere = slight increase in temperature
- Extends from 12km to ~50 km
- Contains the Ozone Layer (absorbs UV to increase temperature)
3. Mesosphere = temperatures decrease with altitude
- No definite upper limit - Temperatures near
-90ºC
4. Thermosphere = temperatures increase due to absorption of high energy solar radiation
- No definite upper limit
Earth’s Orientation
Seasonal changes occur because Earth’s position relative to the sun continually changes as it travels along its orbit.
Solstices
• Summer Solstice: First official day of summer. Northern Hemisphere leaning 23.5 degrees towards sun.
• Winter Solstice: (opposite side of the orbit) December 21 or 22nd. N.H. leans 23.5 degrees away from the sun.
Equinoxes
• Midway between solstices.
• September 22nd or 23rd date of Autumnal Equinox.
• March 21st or 22nd date of Spring Equinox
Heating the AtmosphereHeating the AtmosphereWithin the atmosphere heat is transferred 3
ways:
1. Conduction = transfer of heat through direct contact of molecules
- heat flows from the hotter object into the colder object
2. Convection = transfer of heat by mass movement or circulation within a substance
- heat from below (ground) conducts heat near the base of the atmosphere, the air rises & expands causing cooler air to sink = circulating air patterns within the atmosphere
3. Radiation = heat is radiated (travels by waves) from the sun and hits the atmosphere
- some radiated energy is absorbed and some is reflected (bounced) back into space
~30% is reflected back into space
~50% is absorbed by land & sea
~20% is absorbed by clouds & atmosphere
Greenhouse EffectGreenhouse Effect• Earth’s atmosphere naturally
absorbs heat from the sun because of water vapor & carbon dioxide composition
• The atmosphere also traps heat (infrared waves) near the Earth’s surface
• Without this natural greenhouse effect, Earth’s temperature would be much colder (uninhabitable for humans)
• Increased levels of carbon dioxide (mainly from car exhaust) increases the atmosphere’s ability to trap heat = Earth’s temperature is getting warmer
Global Warming • Increased levels of
CO2 (mainly from car exhaust) which increases the atmospheres ability to trap heat.
• Earths’ Temperature is getting WARMER
Why do temperatures vary Why do temperatures vary so much on Earth?so much on Earth?
5 Reasons:
1. Latitude (distance from the equator)– Differences in amount of solar radiation
received– Variations in the angle of sun’s rays– Length of daylight
2. Heating of land & water- Land heats more rapidly and to higher temperatures than water- Land also cools more rapidly and to lower temperatures than water
- Cities near water have a smaller daily temperature change compared to cities more inland
Continued….Continued….4. Geographic Position (related to
prevailing wind direction)- A town on the ocean, with the wind
blowing in from the ocean, will, experience moderate temperatures (cool summers & mild winters) EX: S. California
- A town near mountains and the ocean will experience moderate temperatures & increased rain because mts act like a barrier to wind & rain
EX: Seattle, Washington
5. Cloud Cover
- Clouds reflect a significant amount of solar radiation
- Cities with lots of cloud cover will have significantly lower temperatures than a location with sunny weather
- Clouds at night keep heat trapped at surface, clear nights allow heat to escape into space and make chilly nights
Albedo- fraction of total radiation that is reflected by any surface
(Clouds have high albedo bc large portion of sunlight is reflected back to spaces.
Word Distribution of Temperature
• Map used to study global temperature patterns and effects of factors on temperature such as latitude, distribution of land, and water and ocean currents.
• Isotherms- are lines that connect points that have same temperature
Ch 17 Final AssignmentTHIS IS WORTH 25 POINTS!
Page 499 - 500
#1, 2, 4, 6, 8 = write out both question and answer
#11, 12, 13, 17, 18, 27 = write out only answers in complete sentences
Vocabulary WordsAutumnal Equinox ConductionConvection Greenhouse Effect
Mesosphere Ozone
Radiation Reflection Spring Equinox StratosphereSummer Solstice ThermosphereTroposphere Winter Solstice
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