Download Ch 12 Act 1 reading lecture in ppt

Climate
Major Factors affecting climate
Latitude Affects Climate
Least Radiation!
Low sun angle & ice
Reflects back sun!
Most Radiation!
Sun directly
overhead
The tilt of the earth determines the amount of
solar energy received by a region.
Most of US in
this area of
moderation!
“Changes in latitude, changes in
attitude…”
Why is it warmer in
Dallas than
Minneapolis?
Dallas gets more direct
rays of sun.
Elevation
• Places at high elevations are generally
cooler than places at low elevations in a
given region. Temperatures decrease 3.6
degrees F for every 1000 foot gain in
elevation.
• This is a reason for glacier formation.
“I left my heart in San francisco…”
What causes San
Francisco’s climate to
be milder than
Wichita, Kansas ?
Ocean waters moderate the
temperatures. Warm
currents can warm the areas
they are near, breezes bring
in more moisture.
Heat Capacity
• The quantity of heat energy needed to
increase the temperature of a substance.
• Formally: the amount of energy required to generate a 1 degree
Celcius rise in temperature of 1 gram of a substance at atmospheric
pressure and 20 degrees C.
Heat Capacity
Air coming off a cold lake or ocean will be
cooler because the water requires more
heat to increase its temperature than land.
Land areas warm up more quickly and cool
down more quickly.
Temperatures over oceans and large lakes
don’t vary as much. As a result, nearby
land will be warmer in the winter and
cooler in the summer. The nearby water
has a moderating effect on land
temperatures.
Oceans
• The ocean stores a much greater quantity
of energy than the atmosphere. This is
due to both its larger heat capacity (4.2
times that of the atmosphere) and its much
greater density (1000 times that of air).
Mountain impact on climate
Cooler!!
Moisture leaves the air as clouds pass over the mountain.
Example: Stampede pass in central Washington gets 91
inches of rain per year. Yakima is east of this and gets an
average of 8 inches per year!
Lake Effect Snow
• Snowfall occurs near the Great Lakes in late
fall and early winter. This is due to cooler air
flowing over the warm lake water. The
moisture in the air cools as it reaches the
colder land creating snow.
Urban Heat Island Affect
Cities absorb a
lot of heat in
the materials
used for
roads,
buildings, and
parking lots.
Cars add to
this. So does
pollution.
Polar areas – the cryosphere
• Reflect sun’s rays off ice, reducing heat
absorption of earth’s surface
• Ice reduces amount of water in oceans that can
absorb and hold heat.
• The cryosphere is a buffer between the
atmosphere and oceans. It stabilizes the energy
transfer between the atmosphere and ocean.
The formation of sea ice begins global
thermohaline circulation patterns in the oceans,
which greatly influence the global climate
system. Polar ice affects the volume of the
oceans and global sea levels, changes to which
can affect the energy budget of the climate
system.
Landforms and climate
• The biosphere, both on land and in the
oceans, affects the albedo (solar energy
absorption/reflection) of the Earth's
surface. Continental forests reflect less
solar energy than deserts. Tropical
rainforest reflects even less energy.
Life forms and climate
• The biosphere also influences the changing
levels of certain greenhouse gases. Plankton
take in dissolved carbon dioxide for
photosynthesis. This gas comes down from the
atmosphere. On death, the plankton sink,
transporting the carbon dioxide to the deep
ocean.
• Millions of spores, viruses, bacteria, pollen and
other minute organic species are transported
into the atmosphere by winds, where they can
scatter incoming solar radiation.
The Geosphere
• Volcanic eruptions replenish the carbon dioxide in the
atmosphere and emit considerable quantities of dust and
other gases like water vapor and sulfur dioxide.
• Soils, sediments and rocks, the continental and oceanic
crust and the Earth’s interior are parts of the geosphere.
They play a role in the regulation and variation of global
climate, to a greater or lesser extent, over varying time
scales.
• Variations in global climate over tens of millions or even
hundreds of millions of years are due to modulations
within the interior of the Earth. Changes in the shape of
ocean basins and the size of continental mountain
chains (driven by plate tectonic processes) may
influence the energy transfers within and between the
coupled components of the climate system.