Answer 1:
The spin of the Earth is not the primary
phenomenon driving motions in the turbulent
atmosphere. In fact, air moves mostly because
the Earth is heated unevenly by the sun.
The rate of solar energy input is a strong
function of latitude. Because there is more
heating at low latitudes, the air there gets
heated and rises. If the earth WAS NOT spinning,
this heated air would rise to the top of the
troposphere and then it would travel north on a
line of longitude and cool off. At the poles it
would become denser than the surrounding air and
it would sink down towards the surface moving
south... as it moved south it would be heated and
find itself again at the equator and hot, and
hence would rise!! This is a GIANT CONVECTION
CELL called the HADLEY CIRCULATION.it
is inequities in temperature that gives rise to
buoyant air and THAT is what drives atmospheric
circulation. The spin of earth does MODIFY the
pattern of air motion, but still the main driving
effect is the redistribution of planetary heat
from low to high latitudes.
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Answer 2:
There are three forces that make air move over the
earth's surface. The Earth's rotation is only one
of them! The Earth's rotation results in an effect
called the "Coriolis Effect" described in
1835 by the French scientist Gaspard-Gustave
Coriolis. But even if the earth stops rotating,
the other two forces will result in winds.
The first force is the due to the difference of
air pressure at nearby locations.
If an area with high air pressure is next to an
area with low air pressure, air will move from
the high to the low pressure. The goal is to
make the two pressures equal. When the pressure
difference is big, there will be lots of air that
will have to move to equalize the pressures. It
will also move fast: the bigger the pressure
difference, the stronger and faster the wind will
be. Which is why big difference in pressure
predict windy days. You don't have to look very
far to see pressure differences. (check it out on
the weather channels maps!)
The sea breeze is an example you can observe:
during the night, the earth cools down and the sea
and earth temperatures are similar. But after
noon, around 2pm, when the sun is high up, the
earth heats up more than the sea, and the air
above the earth heats also more than the air above
the sea. Earth air expands and becomes lighter, so
moves up. That creates a pressure difference: the
coast's earth side has lower pressure then the sea
side and air located above the sea, which has high
pressure, wants to move towards the earth, which
has low pressure, to replace the air that is
moving up. The high and low pressure on the map
tell us the direction of the wind, and you can see
them on all weather channels!
The second reason air moves the way it moves is
friction. Forests, buildings, cities, slow
down the wind because of their uneven surface.
Wind above open sea, flatlands and fields faces no
obstacles and can speed up. Friction also makes
the wind rotate direction as it slows down. If
friction is too much, then the wind can stop.
Knowing these three phenomena, you can predict
the local weather very well from the daily
pressure maps!
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Answer 3:
Interesting question! Air (in the form of wind) is
affected by the Earth’s rotation. But it is also
affected by areas of high and low pressure.
For instance, the air on top of a mountain is
lower pressure and might be displaced by air of
higher pressure at sea level. Also, the Sun heats
up the atmosphere which causes air to flow as it
becomes hotter. The rotation of Earth adds yet
another parameter where you can think of it as the
Earth “dragging” the air around as it spins. An
interesting mathematical theorem you may find
interesting is called the “Hairy Ball”
Theorem. This is a mathematical proof which in
essence says that “you can’t comb a hairy ball
flat without a cowlick.” For application of wind
direction and the Earth, this suggests that if
there is wind on Earth (and there is), at some
point on Earth there will always be a point with
no wind! Think of this as the eye of a cyclone. So
this theorem implies that there will always be a
cyclone at some point on Earth.
hairy ball theorem
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Answer 4:
Heating of air causes differences in temperature,
which causes the air to circulate. Heating of the
air can be accomplished in many ways, such as when
the sun heats the Earth, which then heats the air
up.
For example, think of hot pavement sitting in
the sun at midday, which makes the air hot above
it. You can sometimes see shimmery patterns above
the pavement because the air of different
temperature is mixing with the colder air around
it.
Another example, of course, is the Earth is
covered mostly by water, and water can also be
heated by the sun. The water is then carried into
the air with this heat, and causes circulation.
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Answer 5:
The east-west winds on Earth are largely caused
by the Earth's rotation, but the north-south winds
generally aren't. If the Earth were not spinning,
you could see north-south winds, just not
east-west winds.
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