Transcript EarthsAtmosphere

the state of the
atmosphere at a
given time and place
depends on:
•amount of clouds
•temperature
•air pressure
•wind
•amount of moisture
•A thick blanket of gases
surrounding the Earth
•composed of AIR (a mixture
of gases)
Nitrogen (N)
78%
Oxygen (O)
21%
Also, Carbon Dioxide (CO2), H2O
Vapor, and Argon (Ar) in small
amounts
• Troposphere: layer of the
atmosphere closest to the Earth
 10km above the earth
 where weather happens
 temperature decreases with
height
3 oxygen atoms
bonded together
O is an atom of Oxygen (O)
O2 is atmospheric Oxygen (O-O)
O3 is ozone (O-O-O)
•Absorbs 99% of harmful
ultraviolet rays from the sun
•ozone layer is about 10 to 20 km
thick
•thinning is the result of
chloroflorocarbons (CFC’s)
containing chlorine, fluorine, and
carbon
Stratosphere: second layer of the
atmosphere
 10-50 km above earth surface
 where the 90% ozone layer is
 temperature increases with
height
 where airplanes fly (on edge of
troposphere)
 weather balloons found here
Mesosphere: third layer of the
atmosphere (50-85 km)
 “meso” means “middle”
 where meteors burn up
(shooting stars)
 temperature decreases
with height
Thermosphere: outmost layer of
the atmosphere (85-500km)
 As height increases, temperature
increases
 named for its high temp – but you
would not feel heat b/c there are so few
gas particles due to vacuum (or thin air).
 thickest layer
 where auroras happen
 consists of 2 parts:
Ionosphere & Exosphere
•pressure that the air exerts on
the Earth
•directed equally in all directions
•differences in air pressure
causes the Earth’s winds and
weather changes
•air pressure is affected by:
•temperature
•water vapor
•elevation
instrument used to
measure air pressure
air pressure is reported as:
1. height of mercury column in
barometer
2. .001 of standard sea level a.p.
two types:
mercury
aneroid
lines that join
points on a map
having the same air
pressure
•falling barometer: warmer
weather, humid (rain, snow)
•rising barometer:cooler weather,
drier
Almost all of the Earth’s energy
comes from the sun and is called
radiant energy
•most reaches
the atmosphere
and is reflected
back to space
•Some is absorbed by the Earth
and is spread throughout the
atmosphere as:
•Radiation: transfer of energy in
form of waves
conduction: direct transfer of
energy from one substance to
another
Ex. Bare feet on hot sand
convection: transfer of energy in a
fluid
•air is a fluid- hot air rises, cool
air sinks
As much energy leaves the
Earth that comes in ---> Earth’s
heat is balanced.
greenhouse effect: trapping of
the sun’s energy by the Earth
•caused by the burning of
fossil fuels- coal, oil, and
natural gas- adds CO2 into air
•warming effect may melt
glaciers and raise sea levels
Houston on a smoggy day (left) and a clear
day (right).
All winds result from an uneven
heating of the atmosphere
movement of
air
two types:
(1) local winds
Flow of cool air
from water to land
during the day
wind
Flow of cool air from land to
water at night
wind
monsoons: major
seasonal land and sea
breeze
•most of the year, wind
blows from land to sea
(dry)
•part of year, wind
blows from sea to land
(brings warm, moist air)
(2) global winds
jet stream: narrow belt of
strong, high speed air
•height about 10 to 15 km above
N. and S. Hemispheres
•closely related to weather
http://www.weatherimages.com/data/imag192.html (current position)
Coriolis effect: deflection of wind
and ocean currents caused by the
Earth’s rotation
Winds in N.
Hemisphere
flow to the
right
Winds in S.
Hemisphere
flow to the
left
anemometer: instrument that
measures wind speed
wind vane: measures wind direction
*always points into the wind
wind
This is an easterly wind because it is
blowing from the east
•a measure of the energy in
molecules
•the more energy the molecules
have, the hotter it feels
isotherm: lines on a map that connect
places that have the same
temperature
thermometer: instrument that
measures temperature
•alcohol and mercury
thermometers used (mercury
more accurate)
water freezes at: 0ºC or 32 ºF
water boils at: 100ºC or 212ºF