Transcript The Atmosphere - Kentucky Department of Education

Weather
Bell Ringer: Day 1
In your science notebooks, make a heading for a
new section of notes for our unit of study on
WEATHER.
1.) Pretend that your younger cousin, Becky, asks
you to tell her what weather is. In your notebook,
define WEATHER in your own words
Bell Ringer
1. Hot air or water_____
a.) sinks b.) rises c.) does not move
2. What do we call the movement of hot
water or air? convection
What IS weather?!
(share answers from Bell Ringer)
Weather is “the state of the air and
atmosphere at a particular time and place :
the temperature, wind, moisture, and
atmospheric pressure”.
Examples:
1.) The weather will be hot and dry today.
2.) The hikers took shelter from the weather in a small
cave.
3.) Make sure to check the weather before you pack for
your trip.
* When you see the arrow symbol,, you should be writing
in your notes
Day 1: Introduction
What is the weather that we are
experiencing in Bowling Green, KY
today?
Using the chrome books, find a city in the
United States that is having very different
weather than we are today.
WHY???
1.) Now that we have heard about other
cities, in the same country that we live in
that have very different weather patterns
than us, how can we explain the
difference??
Weather patterns are complex, and very
difficult to predict because weather is
caused by so many different factors.
What causes weather?
The number one cause of weather is
uneven heating of the earth’s surface.
The uneven heating causes temperature
differences, which in turn cause air
currents (wind) to develop, which then
move heat from where there is more heat
(higher temperatures) to where there is
less heat (lower temperatures).
HOT AIR (moves to)  COLD AIR
What do we call the movement of hot air?
CONVECTION
#1 cause of weather: uneven heating
The atmosphere thus becomes a giant "heat
engine", continuously driven by the
sun. High and low pressure areas, wind,
clouds, and precipitation are all caused, either
directly or indirectly, by this uneven heating
and the resulting heat redistribution
processes.
HEAT IS ENERGY, & WILL MOVE UNTIL
EVERYTHING HAS THE SAME AMOUNT
OF ENERGY, OR IS THE SAME
TEMPERATURE
Advanced: Going Into More
Detail
Two main modes of this heat redistribution:
(1) VERTICAL heat transport: Solar heating of the Earth's surface makes
the atmosphere convectively unstable, causing vertical air currents to
develop. This is what causes puffy-looking clouds, showers, and
thunderstorms to form in warm air masses.
(2) HORIZONTAL heat transport: Because the Earth is a sphere, it
receives more sunlight in the tropics, and less sunlight toward the North
and South Poles. This causes horizontal temperature differences to
develop, which in turn causes air pressure differences, leading to wind
that transports heat from the tropics to the high latitudes.
Together, this uneven heating in both the horizontal and vertical
directions in the atmosphere causes everything that we perceive as
"weather".
What causes weather?
Another factor that causes weather is
WATER.
During the water cycle, heat energy is
constantly causing water to change states.
List the 3 states of water:
& put a + over the state with the most energy, and a –
over the state with the least amount of energy
The energy changes during the water cycle
cause weather.
CLOUDS & PRECIPITATION
Wind flowing over the Earth's surface
causes evaporation of surface water.
Does water evaporating gain or lose
energy?
Evaporation requires heat (water gains
energy)
How would water evaporating affect the
temperature of the earth’s surface?
CLOUDS & PRECIPITATION
Water evaporating would cool the surface
of the earth.
Where does water go when its evaporated
from earth’s surface?
After evaporating, water releases that
heat higher up in the atmosphere when
the water vapor condenses to form
clouds and precipitation.
Advanced FYI: This primary mode of vertical heat
transport is called "moist convection".
Diagram of how water can cause weather: In your
packet, draw this diagram, and label the following:
1. evaporation & water gains energy, 2. surface
cools, 3. condensation releases heat energy
The following photo from the Space Station shows a large thunderstorm,
which represents moist convection transporting heat from the lower to
the upper atmosphere:
What causes weather?
Now that we have seen an example of how water affects weather, we
need to know some important terms:
1. Humidity = the amount of water vapor or
moisture in the air
2. Relative Humidity = is the amount of
moisture in the air compared to what the air
can "hold" at that temperature
Humidity
How does humidity cause or affect weather?
Air Pressure & Air Masses
The two causes of weather that we have
learned about are : uneven heating of
the earth’s surface, & water. Now, we will
learn how meteorologists combine these two
causes to predict weather.
Have you ever wondered how a day could
begin warm, and you could wear shorts in the
morning, and by the evening you need a
heavy coat???
Air Masses!
Changes in weather are caused by the
movement and interaction of air masses.
Hot, Dry Air + Cold, Moist Air = WEATHER!
Two main characteristics define
air masses:
1.) Temperature
2.) Moisture content
The temperature and moisture content of air
masses are abbreviated as two letters. The
first letter is a lower case letter and is used
to symbolize the overall moisture in the air.
The second letter (capitalized), symbolizes
the temperature.
Example of air mass
One example of an air mass
: continental tropical (cT)
The air mass symbol “cT” tells scientists that
the air is:
c = continental, or formed over land, so it
has less moisture than air formed over
water.
T = Tropical, or formed in a warm area
(close to equator)
4 Types of Air
•
•
•
•
continental air - c
maritime air - m
Tropical air - T
Polar air - P
Based on the names (above), can you
describe each of the types of air ?
Types of Air
• continental air c= Any body of air that forms
over a large land area and has low moisture.
• maritime air m = Air that forms over a large
body of water and is usually moist. Also called
“oceanic air”.
-Maritime air masses are unique because they usually stay the same & resist
change! Why do you think that is?
Tropical air T = air formed in
regions where the temperature is warm. A tropical air
mass tells us the air is warm and formed in the lower
latitudes (close to the equator).
• Polar air P = air formed in regions where the
temperature is colder.
1.) Compared to tropical air, where do you think Polar air forms?
2.) Pause for a moment, & identify the opposite of each type of air.
3.) Why are Tropical (T) & Polar (P) air capitalized, while Maritime (m) &
Continental (c) are lower case?
Opposite Air Masses
Continental (formed over land) , opposite of
Maritime (formed over water)
-Maritime is AKA (also known as) “Maritime
front”, “MAMS”, or “oceanic air mass”
Tropical (is hot or warm), opposite of Polar (cold)
•
•
•
•
Air masses:
Types of Air:
continental air - c
maritime air - m
Tropical air - T
Polar air - P
• maritime tropical
(mT)
• continental tropical
(cT)
• maritime polar
(mP)
• maritime tropical
(cP)
1. maritime Tropical
(mT)
2. continental
Tropical (cT)
3. maritime Polar
(mP)
4. continental Polar
(cP)
1. Moist & Warm
2. Dry & Warm
3. Moist & Cold
4. Dry & Cold
Scientists sometimes need a more extreme description for VERY cold air…& they call it
“Arctic” air instead of Polar.
What type of air mass would
this be?
Can you guess what type of air forms off the
north west coast of the U.S.A., by the state
of Washington & Canada?
Which types of Air Mass it will be is
determined by where the air mass comes
from; not where it travels to.
What type of air mass would
form here?
What type of air mass would
form here?
Atmosphere Definition
The layer of gases
surrounding Earth;
composed mainly
of nitrogen and
oxygen
78% nitrogen
21% oxygen
1% other
Layers
http://www.fi.edu/wright/again/wings.avkids.com/wings.avkids.com/Book/Atmosphere/Images/atmos_layers.gif
Troposphere
• Where all plants and
animals live and
breathe
• Where weather takes
place
• 90% of the mass of
the atmosphere
• Thinnest layer
• Temp decreases with
altitude
http://atschool.eduweb.co.uk/kingworc/departments/geography/nottingham/atmosphere/pages/gfx/troposphere.jpg
Stratosphere
• Ozone in this layer stops many of the
sun's harmful rays from reaching the earth
• People can not breathe in this layer.
• Temperature increases as altitude
increases
• Keeps air warm and protects life on Earth
Ozone Layer
•Pale blue gas with a strong odor.
•90% of all ozone is found in the
stratosphere
•10% is found in the troposphere
•Ozone is extremely important
because it is the only gas that
absorbs ultraviolet radiation
from the Sun and protects the
surface of the Earth and people
from the damaging effects of UV
rays
http://ess.geology.ufl.edu/ess/Notes/090-Ozone_Depletion/depl2.jpg
Mesosphere
• Meso = middle between strato and thermo
• Windstorms reach speeds of 320 km/h
• Temp decreases with altitude
– coldest layer (-93 degrees C)
• This is where we see "falling stars" –
meteors burning up as they fall to Earth
Ionosphere
• An extension or a part of the
upper mesosphere and lower
thermosphere. So technically,
the ionosphere is not another
atmospheric layer.
• Composed of electrically
charged particles
• Auroras take place in this
area
• Radio waves are reflected by
this layer
Thermosphere
• Layer of the atmosphere which is first
exposed to the Sun's radiation
• Temperatures are very high, but doesn’t
feel hot because particles don’t transfer
energy
• The air is very thin
Exosphere
• Highest layer of the atmosphere. The air is
very thin here
• Atoms and molecules escape into space
Let’s look at an animation:
http://earthguide.ucsd.edu/earthgu
ide/diagrams/atmosphere/index.ht
ml
Air Pressure
HIGH AND LOW PRESSURE AREAS
• Uneven heating of the earth’s surface
causes high and low pressure areas to
develop.
• Wind is caused by air flowing from an area of
high pressure to an area of low pressure.
-Wind’s direction is influenced by earth’s
rotation, which makes things complicated!!!
HIGH  LOW
Wind wants to flow from high to low
pressure areas, but the rotation of the earth
prevents this
• So, instead, wind flows AROUND areas of
high and low pressure.
• Clockwise around high pressure, counter
clockwise around low pressure
• The diverting effect of earth’s rotation is
called the Coriolis effect
Advanced FYI
• The horizontal transport of heat by
wind from low (equator) to high
latitudes (like Greenland) is strongly
influenced by the Earth's rotation,
which prevents the wind from flowing
directly from high pressure to low
pressure, and instead causes the wind
to flow around high and low pressure
centers.
Coriolis Effect
• The following example shows how the
wind flows in the Northern
Hemisphere...in the Southern
Hemisphere, the wind flows in the
opposite direction around high and low
pressure areas.
• This diverting force is called
the "Coriolis effect".
• The spiral shape of cloud
systems can be clearly seen
from space, such as in this
famous photo taken by
Apollo 17 astronaut Harrison
Schmitt, and is evidence of
the Coriolis effect.
I want students to use DE to get
this info….
• How Does the Movement of Air Masses
Affect Weather? (fronts)
•
Meteorologists focus a great deal on the study ofweather patterns known
as fronts. Fronts are the boundaries between large masses
of air. Airmasses form over large areas of Earth’s surface and take on the
general temperature and moisture characteristics of the area over which
they form. As an air mass moves across a region, the location of a front will
change. Air masses are generally defined by their
overall temperature andair pressure. As these air masses move and collide
with one another, different types ofweather can occur along a front.
Advanced: Big Picture
• All of these horizontal and vertical heat
transport processes produce complete
atmospheric circulation "cells". This is
a consequence of the fact that for all of
the air transporting heat from higher to
lower temperatures, there must also be
a return flow of air in the opposite
direction.
Advanced: Big Picture
• For instance, for all of the air rapidly rising within
a thunderstorm, there must be an equal amount of
air sinking elsewhere. This sinking occurs over a
much broader area than the strong updrafts in the
thunderstorm, and the rate of sinking is more
slower. This is why you feel turbulence when
flying through clouds, but not so much in the clear
areas around the clouds. The distances involved
in the circulation cells is typically tens of miles.
General: Big Picture
The movement of air from areas of high
to low pressure forms atmospheric
circulation cells.
Conclusion (adv & gen)
•
So, when you experience a clear day without a cloud in the sky, you
are in the descending branch of an atmospheric circulation cell. That
descending air is being forced downward by rising air in precipitation
systems hundreds or even thousands of miles away. Then, because
these circulation cells tend to travel, in a day or two you find yourself
in the ascending branch of a circulation cell, with clouds and rain (or
snow).
If all this sounds complicated, that's because it is. But remember, all of
this complexity we experience as "weather" is ultimately the result of
uneven heating of the Earth by the sun, and the atmosphere
continuously 'trying' to reduce the resulting differences in
temperature.