Download Climatic Changes

Climatic Changes
Standards


4d: Students know the differing Greenhouse
conditions on Earth, Mars and Venus; the origins of
those conditions; and the climatic consequences of
each.
5g: Students know the features of the ENSO cycle
in terms of sea-surface and air temperature
variations across the Pacific and some climatic
results of this cycle.
Seasons



Short-term periods of climate change
caused by regular variations in
daylight, temperature and weather
patterns
Variations are due to changes in the
amount of solar radiation an area
receives
Once Earth revolves at a tilt, different
areas of earth receive changing
amounts of solar radiation
Seasons
Effects of Latitude


Middle latitudes have fairly constant solar
radiation so there is little change in
seasons. There are changes in wet and
dry seasons
Higher latitudes near the poles experience
great differences in temperature and in
number of daylight hours.
South & North Poles


During the summer the North Pole is tilted
toward the sun, at this location there are 24
hours of daylight for six months
At the same time in the South Pole
experiences 24 hours darkness
El Nino



Occurs every three to five years and
lately more often
During El Nino the Pacific Ocean
warms along the equator
Near the equator trade winds blow
east to west weaken and sometimes
reverse.
El Nino Cont.



Instead of cold water rising off the
coast of Peru, the change in the trade
winds allows warm tropical water in
the upper layer of the Pacific to flow
eastward to South America
Ocean temperatures increase by 1
degree C to 7 degrees C off the coast
of Peru.
Sea levels rise
However, El Nino…..

Does not directly cause unusual
weather but instead affects the
atmosphere and the ocean to make
stormy weather more likely.
Climatic Change




Earlier geologic eras show that Earth
was sometimes much colder or warmer
than it is today
Glaciers have covered large parts of
Earth’s surface
These periods of extensive glaciers are
called ice ages
Ice ages alternate with warm periods
called interglacial intervals
Greenhouse Effect


Natural heating
caused by gases in
our atmosphere
trapping heat
Carbon dioxide is
the main
greenhouse gas
Global Warming



Global temperatures are rising
Increased greenhouse gases increase
the greenhouse effect
Temperatures on Earth have risen ½
degree C in the last 100 years
Global warming has a huge
effect on Earth!
Greenhouse warming
What about other planets?

Venus
– Most similar to earth in physical properties such
as mass, diameter and density
– Average surface temperature is 464°C
– The atmosphere is mainly Carbon Dioxide and
Nitrogen.
 Causes a highly efficient Greenhouse Effect
resulting in very high temperatures.
– It has clouds made of sulfuric acid
– The atmospheric pressure is 92 atmospheres,
compared to 1 atmosphere at sea level on Earth.
What about other planets?

Mars
– The planet is smaller and less dense than Earth.
– The density and atmospheric pressure on Mars is
much lower than Venus
– There is a very thin atmosphere
 95% Carbon Dioxide
 5% Oxygen, Nitrogen, Argon
– Because of this Mars does not have the strong
Greenhouse Effect found on Venus.
– Mars has high turbulent winds
The Coriolis Effect




It is important because:
It controls the global circulation patterns of the atmosphere
– Climate zones
– Rainfall patterns
– Surface wind patterns
It affects global ocean circulation patterns
– Coastal currents
– Westward intensification of coastal currents
– Heat transport from equator to the poles
It affects ocean mixing through the Eckman Spiral
– Upwelling
– Surface mixing
To understand Coriolis, we:


Use the analogy of a carousel with two
people playing catch.
The carousel rotates during the game
– Analogous to earth rotation

We observe the game of catch as if we were
seeing it from:
– 1. A high, fixed platform (analogous to outer
space).
– 2. A platform that rotates with the carousel
(analogous to our location on the rotating
earth).
–
Play Video
Limitations of the
analogy:


The analogy is that the earth is
represented by the carousel and the
“fixed” observer is an “inertial” frame
of reference, where objects travel in
straight lines.
The observation is from above, so it
only applies to the earth if the
carousel is at the north or south pole.
Coriolis on the Earth


Mass in motion curves to the right in
the Northern Hemisphere and to the
Left in the Southern Hemisphere.
The Coriolis effect is strongest at the
poles and weakest at the equator.
Atmospheric Circulation if
earth doesn’t rotate
If the earth were a nonrotating sphere, air
circulation would be in a
single Northern Hemisphere
cell and in a single Southern
Hemisphere cell.
In each cell, heated air
would rise at the equator
and move toward the polar
regions, where it would cool,
sink, and be drawn back to
the warmer regions of the
equator.
Review Sheet






What are seasons?
Explain how the tilt of the earth effects
seasons.
How does El Nino occur?
What is the effect of El Nino?
In depth explain the Greenhouse effect
and the impact of earth.
Why is global warming occurring and
how does it effect earth?