Download Ozone Layer. - Teacher Pages

Earth’s Atmosphere
and Weather
The earth has layers on the inside and layers
on the outside, aka the atmosphere.
From the outside in:
Thermosphere - Hot outer layer, hit
by a lot of solar
radiation. Temps at
~ 980oC or 1,796oF
Ionosphere - The lower Thermosphere and
upper Mesosphere, filled with
ions that bounce radio waves
long distances across earth.
Mesosphere - This layer doesn’t absorb much
radiation, so the temp drops to
below -80oC or -112oF
Ozone Layer - The top layer of the Stratosphere has a
lot of ozone molecules which absorb and
react with UV radiation that got through
.
the upper layers.
Stratosphere - The bottom of the stratosphere is very cold at
~ -55oC or -67oF, but the
top is warmer at ~0oC
from the reactions in the
Ozone Layer.
Troposphere - The troposphere refers to every
part of the atmosphere that is below the stratosphere all the way to the ground. Most
weather takes place in this layer.
The earth’s atmosphere is mostly made up of:
Nitrogen (78%), Oxygen, & Carbon (CO2)
The oxygen comes from
photosynthesis of plants,
algae, and bacteria.
O2
O2
The nitrogen and carbon can come as wastes
from living things as they
consume nutrients.
The nitrogen and carbon can also come from
combustion
.
reactions such as burning gasoline
or can come from erupting volcanoes.
The Water Cycle
Water turns into steam by evaporation (oceans and lakes) and
transpiration (evaporation directly from plant leaves).
It then
condenses in
the lower
atmosphere &
eventually
precipitates as
rain, snow, etc.
The water then
flows over the
ground as
rivers and
under the
ground back to the oceans, lakes and plants.
When air warms up, more water evaporates or
transpires. This makes warm, humid air and
when you warm a fluid, the warm, humid air will
expand, become less dense and rise.
As the air rises, it cools and then it will become
more dense and it will eventually sink.
Warm, expanded, low density, rising, humid air
pushes down on the bottom of the atmosphere
with low-pressure.
Cooling, high density, sinking, dry air pushes
down on the bottom of the atmosphere with
high-pressure.
High pressure systems push hard and lowpressure systems push weakly, so air moves
from high to low.
Whenever warm air rises, it has
to eventually fall. Most of the
rising warm on the Earth occurs
at the equator.
After moving away from the
equator and rising to the cold upper atmosphere,
the air cools and sinks back down.
So, there is a continuous flow of warm air
moving in the upper troposphere from the
southwest to the northeast and cold air
moving in the lower troposphere from the
northeast to the southwest.
This push of air is usually
called wind.
Sometimes, this movement comes in spurts
where a large mass of warm or cold air will
suddenly move into an area.
If a large mass of warm, humid air suddenly
runs into a pocket of cold air, then the warm
air will rise above the cold air and the water
vapor in it will cool and condense to make
clouds and slow, steady precipitation that will
usually last a few days.
If a large mass of cold, dry air suddenly runs into a
pocket of moist, warm air, then the cold
air will plow under the warm air, forcing it to rise very
quickly. As the warm, humid air rises and cools
quickly, a great deal of wind is made, big clouds form
very quickly and a lot of rain comes down, frequently
as big storms. This is a COLD front.
The big masses of moving warm air are called
. warm fronts and they generally make steady
rain or snow as they pass through.
The big masses of moving cold air are called
cold
fronts and they generally make big
.
cumulonimbus clouds and storms.
Occluded Front
• When a warm air mass is caught
between two cooler air masses. The
warm air rises, is trapped, cools, and
forms cloudy skies and rain.
When storms occur and warm air rises rapidly, it can
start circulating in the clouds due to the Earth’s
rotation.
When a vertical cylinder of rotating air
develops, it can sometimes sink down to
touch the ground as a tornado.
As very warm air rises off of warm, tropical oceans, it
can cause a chain reaction of rising, moist air leading to
condensation and eventually a huge amount of
circulating cold air, plummeting back to the ground
very fast as a
hurricane
(>119km/h).
Stationary Front - When two unlike air masses form a
boundary, but neither is moving.
Cyclone - a weather system with a center of low
pressure.
Anticyclone - has a center of high pressure and
clockwise winds in the Northern Hemisphere.
Generally clear weather is seen with this.
Weather map symbols:
1. cold front;
2. warm front;
3. stationary front;
4. occluded front;
5. surface trough;
6. squall/shear line;
7. dry line;
8. tropical wave
Isotherms - lines on a weather map connecting points with the same
temperature.
Climate - a description of the pattern of weather over a long time in a region.
Temperature and precipitation are the two main factors that determine a
region’s climate.
Earth’s Motion
Rotation - Spinning of the
Earth on its axis .
One Rotation = 1 day
Revolution - The time it takes
the Earth to go around the sun
once is 365.25 days. Also
known as an orbit.
One orbit for the
Earth takes one
year.
Latitude Zones
Polar
Temperate
Equator
Temperate
Polar
Notice how the
run’s rays are
spread out
toward the
poles but hit
more directly
at the equator.
How would
this affect
weather?
Colder toward
the poles &
warmer at the
equator.
If 30% of the
energy reaching
earth is
reflected back
into space and
about 20% is
absorbed by the
atmosphere,
how much will
be absorbed by
the surface of
the Earth?
The Earth’s
atmosphere is heated
mainly by energy
reradiated by Earth’s
surface.
Heating the Earth
Winds are caused by
differences in air pressure.
Local winds occur where
land meets a large body
of water.
Global winds blow over
long distances from a
specific direction
Trade winds, westerlies,
& polar easterlies
are global winds.
See page 758 in your book.
The Jet Stream is a belt of high-speed winds in the
upper troposphere.
Clouds - a dense, visible mass of tiny
water droplets and ice crystals.
The main forms are: stratus, cumulus,
and cirrus..
• Flat layered clouds are stratus (spread
out)
– Nimbostratus produce precipitation
• Cumulus are puffy fair weather clouds
– Thunderheads or cumulonimbus produce
thunder, lightning, and precipitation
• Cirrus are thin, wispy clouds found at high
altitudes
– These generally produce no rain
cumulus
nimbostratus
cirrus
cumulonimbus
Precipitation
• The amount of water in the air is called
humidity. The amount of humidity
present is dependent upon temperature
• At high temps, the air holds more
moisture as vapor. At low temps, this
vapor condenses and forms dew, clouds,
frost (if cold enough) or fog.
• Both rain and freezing rain can fall as
liquid.
• Hail is solid pieces of ice >5 mm in diam.
Continental polar
air masses form
over land north of
50 o north latitude.
• A aa
A Maritime tropical
air mass will form
over a large body of
water affecting
weather of land
nearby.
Several
factors that
can affect a
region’s
temperature
are:
1.Ocean currents
2.Latitude and altitude
3.Distance from large
bodies of water
Etc.
• As altitude increases, temperature falls 6.5
oC per kilometer. If the temperature at
1000 m is 20oC, what would the
temperature be at 3000 m?
• The change in altitude is 2000 m or 2 km.
• 2km x 6.5oC = 13oC fall
•
km
• So: 20 - 13 = 7oC at 3000 m
Another Etc.
• Oxygen makes up about 20.9 % of the
volume of dry air. About how much oxygen
would there be in a 3000 m3 volume of dry
air?
• 3000 m3 x 0.209 = 627 m3