WEATHER
what is happening in the air,
right here,
right now
Climatelonger term weather patterns
over larger areas
4 main components to the weather
1. Air– what it is made of, how
it is moving
2. water– precipitation, humidity
3. Heat
- solar powered
4. Landforms
- ocean vs. land, altitude
The atmosphere
•
a blanket of gases, dust, and vapor surrounding the Earth
held there by Earth’s gravity
•
Early atmosphere was high in carbon dioxide (92%) from
volcanoes
•
•
as the first bacteria and plants lived they used
carbon dioxide and released oxygen changing the
atmosphere
•
•
today’s atmosphere has much less carbon dioxide
(less than 1%), and much more oxygen (21%) and much
more nitrogen (78%)
The atmosphere
• Water vapor is between 0-4% depending on
the location (desert, rain forest)
• Argon = 0.93%
• Carbon dioxide = 0.038%
• All other gasses = 0.015%
bad OZONE
• "Bad" ozone is at ground level.
• forms when pollutants from cars, factories and
other sources react chemically with sunlight.
• smog
• It is usually worst in the summer.
• harmful, causing coughing, asthma, bronchitis
and emphysema, and even permanent lung
damage
•
Good OZONE
added to the atmosphere (20 miles up)
by lightning
• changed normal oxygen (O2) to ozone
•
important to life on Earth because
it is a protective shield from
ultra violet light which can
cause cancer .
(O3).
Current problem
• The ozone layer was getting thinner as
– freon gas was leaked into the atmosphere from
refrigerators and air conditioners.
– CFC (CF2Cl2)aerosols have been sprayed
– CFC alsoused to produce styrofoam
• In the late 1920s, a research team was formed by
Charles Franklin Kettering in General Motors to find a
replacement for the dangerous refrigerants then in
use, such as ammonia.
Montreal protocol 1987
• Most industrialized nations banned the use of
CFC in aerosols, freon refrigerant, and stopped
using them in the production of styrofoam.
• Freon first replaced with R-22 low ozone
depletion potential.
• HCFC-22 thought to be safer, but still affects
the ozone
• 1990 Clean Air Act -“Pureon” R-410A
• new refrigerants
Greenhouse Affect
A greenhouse stays warmer than the outside
because
1) short radiation waves from the sun can
pass through the glass into the greenhouse.
2) the
materials
inside
the gets
greenhouse
absorb
Same
reason
your
car
hot with
the short waves and release longer waves of
the windows
rolled up in the sun.
Infrared radiation
3) the longer waves cannot pass back out
through the glass so the heat gets trapped
inside
http://www.youtube.com/watch?v=5
zLuqSYF68E
• Gases in the atmosphere, such as carbon dioxide
CO2, insulate the Earth.
• Other greenhouse gases = water vapor, methane,
nitrous oxide, CFC’s
• act like the glass in a Greenhouse or in your car.
• keep some of the heat in.
• (average earth temp is about 59`F)
• This is good because…The earth would get terribly
cold at night with out this blanket of insulation
(average earth temp would be 34`F)
[moon day = + 170` F
Moon night = -260`F]
This could be bad if…
• Too much carbon dioxide builds up
• burning fossil fuels
• adds to earth’s insulation keeping more and more
heat in
• the Greenhouse
• Global Warming
Affect.
• Venus’ temperature = 800-900` F from super thick
atmosphere ( 90 times denser than that of the Earth)
Global Warming
last two decades of the 20th century
have been hottest in the last 400 years
Sea levels have risen about 7 inches in the
in the last 100 years, which is more than
the previous 2000 years combined
January Was the Third Warmest
on Record Globally
Earth
is the
Goldilocks planet
Not too hot and not too cold !
Temperature-earth is solar
powered
1. thermometers work by expansion
and contraction
•
liquids expand as they have
more energy so the move up the
thin column.
•
liquids contract as they cool off,
causing the liquid to move down.
“Kinetic Theory of Molecular Motion”
2. bimetal thermometers have two layers of
metals that expand at different rates causing
the strip to curve.
•
Heat transfer
1. conduction –
when one object touches
another and passes the heat
along.
– Warm bare feet on cold floor.
– You touch a hot plate.
– Air above black pavement
gets hotter as air touches the
pavement
– NOT very often a
WEATHER factor
Heat transfer
•
•
•
•
•
2. convectionwhen a fluid (liquid or gas) moves
It is a result of density changing
as the temperature changes
Hot water “rolls” in a pan/beaker
Warm air rises and mixes with cooler air
Very important in weather
Cooler water sinks to the ocean floor
Hot lava rises, cold rock sinks (plate tectonics)
NYE
Heat transfer
3. radiation – when
energy travels through
space in infrared energy
waves
•
This is how energy
gets from the sun to
earth.
• NYE
Weather Maps
Weather Maps
1. isotherms = (equal) (temperatures)
• lines that connect points of equal temperature
• similar to contour lines, follow same rules
Weather Maps
• . Isotherms:
• When color bands
are narrow, the
temperature is
changing rapidly;
likely to storms
Weather Maps
2. isobars (equal) (pressure)
lines that connect points of equal air pressure
Weather often moves from High air pressure to Low air
pressure
isobars
 The cloud core is often located near the LOW
air pressure center.
.
isobars
Winds spin clockwise around
a HIGH air pressure core
isobars
 Winds spin counterclockwise
around a Low air pressure core
isobars
 Fronts are most often found along rapidly
changing isotherms. Especially where warm
air is being quickly changed to cooler air.
 Cloud legs often spin off the core along these
same lines of rapidly changing temperature
 It is windiest where rapidly changing
isotherms.
Weather Maps
• 3. warm fronts – on a map,
point the direction the warm air
is moving
Warm front from the side.
They form gradually lowering clouds as the
high, warm, less dense air arrives first.
Weather Maps
4. cold fronts- , point the
direction the cold air is
moving
Cold front from the side.
They form a sudden tower of clouds
as the low, cold, more dense air runs
into the warmer air.
5. stationary fronts – sometimes neither
side is moving the other
Today’s weather ?