Download air

Review
A- Albedo
•
•
Is the % of solar radiation reflected by an object or
surface
Higher albedo = more radiation reflected by the
surface
•
Albedo, together with reflection by the atmosphere,
thus decreases the amount of incoming radiation that
actually absorbed by Earth
•
High or low albedo?
a.
b.
c.
d.
A mirror
: ___________
A lawn
: ___________
A sidewalk
: ___________
An asphalt driveway : ____________
Albedo
•
•
Is the % of solar radiation reflected by an object or
surface
Higher albedo = more radiation reflected by the
surface
•
Albedo, together with reflection by the atmosphere,
thus decreases the amount of incoming radiation that
actually absorbed by Earth
•
High or low albedo?
a.
b.
c.
d.
A mirror : high
A lawn
: low
A sidewalk
: low
An asphalt driveway : low
8.8 Global Energy Transfer
8.8 Global Energy Transfer Intro
• The equator receives more
radiation than the poles  Earth is
not heated evenly.
• Energy is transferred from equator
to the poles
• Water in the hydrosphere and air in
the atmosphere act as heat sinks,
storing a great deal of thermal
energy
• Comparing the same volumes,
liquid water can hold more thermal
energy than air
How is energy transferred in the atmosphere?
https://www.youtube.com/watch?v=WXuGYSM2D8k
Atmospheric circulation
• Air at equator heats up, moves up
in the atm and becomes less dense
 creating areas of low pressure
underneath (less matter)
• Air cools and sinks towards the
poles  creating areas of high
pressure
•Air flows from high to low pressure creating wind.
•Earth has permanent bands of high and low air pressure, thus
there are prevailing winds that blow in the same direction almost
all the time.
•Due to Earth’s rotation, prevailing winds curve instead of moving
directly north or south. They also push warm ocean water to the
poles
Energy transferred in the atmosphere
• Convection currents:
- a circular current in fluid (e.g.
air, water) caused by rising
of warm fluids as cold fluids
sinks
- Cold air holds less moisture
and is drier than warm air
https://www.youtube.com/watch?v=WXuGYSM2D8k
•The Coriolis Effect
•Air a the equator is rotating
faster than air near the poles
•Faster air moving towards the
poles “gets ahead” of the
surface and appears to shift
eastwards (as viewed from
space).
•Slower air moving towards the
equator (from poles) “lags
behind” the rotating surface and
appears to shift westwards (as
view from space)
https://www.youtube.com/watch?v=i2mec3vgeaI
ENERGY TRANSFER IN OCEANS
How prevailing winds influence climate?
• Origin of prevailing winds
(PW) influence whether
climate is moist or dry
• As PW pass over ocean,
H2O vapour is picked up,
When reaches land, it
becomes rain
• If PW come from poles,
it’s cold and dry
Oceans- the driving forces of
climate and weather
• https://www.youtube.com/watch?v=6vgvTeuoD
WY
How is energy transferred in the ocean?
• Generally moves warm water from the
equator to the poles and cold water
from the poles to the equator
• Ocean currents are driven by
1. surface winds (i.e. prevailing winds)
2. differences in salinity and
temperature of ocean water.
Demo
• https://www.youtube.com/watch?v=4V5cOPK
GEyE ( a more ideal version if we have the
equipment)
• https://www.youtube.com/watch?v=_Ww6BIy
3nc0 ( we did)
2. Ocean Current caused by different in
density and temp. of water
• Different seawater densities due to
a. Cold water is denser than warm water
b. Near the poles, ice is formed from fresh
water leaving behind more salt in the
remaining water (i.e. increasing sea water’s
salinity)
• Different seawater temperature:
• Warm currents float while cold currents sink
The Ocean Conveyor Belt
Thermohaline circulation: the continuous flow of water around
the world, driven by temperature and salinity differences
https://www.youtube.com/watch?NR=1&v=SdgUyLTUYkg&feature=endscreens
Examples of effects of Ocean currents
• Brazil receives a warm ocean
current making the climate
warm and moist allowing
rainforest to flourish
• At the same latitude, Peru
receives a cold ocean current,
making the climate cool and
dry (Atacama Desert in Peru)
• http://oceanexplorer.noaa.gov/edu/learning/player/lesson
08.html