Atmosphere and Ocean
Weather is the day-to-day conditions of the
atmosphere. It is caused by two main things:
unequal heating of the earth’s surface by the sun
earth’s rotation on its axis
El Nino – 3rd greatest cause of the weather
The unequal heating is caused by the earth’s tilt
and curvature. The earth’s rotation causes wind
and ocean currents. Some parts of the earth get
hotter than others, and the heat is spread around
unequal heating causes vertical winds – hot
by the atmosphere. air rising and cold air sinking
Greenhouse effect; Yeah!
See page 5
earth’s rotation causes horizontal or straight wind;
earth rotates more than 1000 mph at the equator
The atmosphere is the area of gases that
surrounds the earth. It is held to earth by
gravity. The air you breathe is part of the
atmosphere. Air is a colorless, odorless, and
tasteless mixture of gases. It is matter and takes
up space (mass
and volume). The
atmosphere has
the following
ingredients:
Why is the sky blue
if gas is invisible?
Inert means that it will not chemically react with anything,
air on the ground – sea level
won’t stick to anything
Atmosphere and Ocean - 2
nitrogen - 78% of the atmosphere; inert gas; dilutes oxygen;
mostly useless for animals in its pure form; bacteria “fix”
nitrogen and turn it into nitrates and nitrites which are used by
plants and animals to make proteins and DNA Nitrogen cycle Yeah!
oxygen - 20% of the atmosphere; used by plants and animals
for respiration - breathing and making food; includes ozone - a
poisonous bluish form of oxygen with a strong odor; when
ozone is produced on the ground from cars and factories, it is
harmful and forms smog; from the middle to the top of the
stratosphere is the ozone layer; the ozone layer acts like a
shield that absorbs the sun’s ultraviolet (UV) energy which is
destructive to life and causes cancer.
water vapor - varies between 1 to 4% of the atmosphere;
heavy greenhouse gas; absorbs heat
argon - 1% of the atmosphere; inert gas (does not combine with
anything); used in welding
carbon cycle Yeah!
carbon dioxide CO2 - 0.04% of the atmosphere; produced when
materials burn (combustion) and when humans and animals
breathe out (respiration); heavy greenhouse gas; absorbs heat
methane, hydrogen, CFC’s - trace greenhouse gases, less than
1 % of the atmosphere
trace = small amount
helium, neon, krypton, xenon, radon - other inert trace gases,
less than 1 % of the atmosphere
Atmosphere and Ocean - 3
The atmosphere has five main layers which are
identified mainly by their:
change in temperature – main way we tell them apart
pressure/density – how heavy are the gasses
content – what types of gasses If heavy gases sink,
what do light gases do?
The atmosphere extends out about 41,000 miles
from earth’s surface to outer space, but most of the air
is concentrated into the bottom two layers (troposphere
and stratosphere - 0 to 30 miles above the ground) due
to gravity. The layers beginning from the surface are:
troposphere, stratosphere these two are the lower atmosphere
mesosphere, thermosphere these two are the upper atmosphere
ionosphere = lower thermosphere; exosphere = upper thermosphere
Heavier gases separate from lighter ones and are
near the surface. Different gases absorb different
amounts and types of solar energy. This is why the
temperatures change through the layers. From the
ground, the temperature first decreases, then
increases, then decreases, then increases, then
decreases to outer space. Each layer has a top part,
called a p a u s e , where the temperature stays the same
for a distance.
Atmosphere and Ocean - 4
The troposphere is about 5-11 miles deep (26,000 to
60,000 ft). It is the layer closest to earth and contains
most of the air. The troposphere is where weather
happens. Temperatures drop as you move away from
the earth (go higher). The top part of the troposphere
is called the tropopause. It acts like a lid to keep water
vapor and other heavy greenhouse gases in the
troposphere. The temperature stops dropping and
is heavy so it stays in the troposphere. So, all weather
remains at -76°F. Water
happens in the bottom layer of the atmosphere.
The earth’s atmosphere spreads out the heat from
the sun, so the
earth has an
even
temperature.
The worldwide
average
temperature
on the ground
or standard
atmospheric
temperature is
59°F or 15°C.
+136°F Libya Africa;
+134°F Death Valley CA;
-129°F Antarctica;
-80°F Alaska
Moon: +253°F to -387°F
Space: -454°F
absolute zero: -459°F
Does earth’s average atmospheric temperature always stay the same or does it
change over time? What could cause it to rise or drop?
Atmosphere and Ocean - 5
The greenhouse effect is the trapping of heat by the
tropopause. Life on earth could not exist without it. Radiant
energy is both absorbed by the ground and reflected back to
the atmosphere. Heavy greenhouse gases in the troposphere
such as carbon dioxide, water vapor, and methane absorb the
reflected energy and reflect it back to earth. Much of the
heat is trapped like a blanket. The amount of energy trapped
depends on the contents of the troposphere. Venus has a
much thicker atmosphere causing its average temperature to
be almost 900°F, while Mars has a much thinner atmosphere
causing its average temperature to be around -81°F.
Changing the atmosphere and ocean content: volcanic eruptions, plate tectonics, pollution
Changing the amount of heat: Milankovitch cycle (earth’s tilt), sun spots
What could happened if the earth’s average temperature increases a little in a short
time? melting ice; less land; less food; more rain; flooding; economy – energy, fuel;
animal extinctions?
Atmosphere and Ocean - 6
Adding extra gases such as CO2, ozone, methane, and CFC’s
from car exhaust fumes and factory emissions increases the
amount of trapped energy in the troposphere. Global
warming, sometimes called the enhanced greenhouse effect,
refers to the increase in
global average temperature
potentially due to human
activity. A rise in global
temperatures could mean
higher sea levels, less land,
different vegetation - direct
impact on human civilization.
What could happened if the earth’s average temperature decreases a little in a short
time? less plants, animals, food; droughts; economy – heating prices, fuel/energy
There are
extremist positions that
people take on both sides
of the issue of global
warming. Some think
that human beings have
totally caused the
recent rise in global
temperatures, while
some think that humans
have not had an effect
at all on climate change.
What is Cap and Trade? The government wants to limit the amount of CO2 emissions
that factories can produce. Companies can sell their pollution to other companies if
they don’t pollute. PROBLEMS: Big Tax on companies – higher prices. Is pollution
really being reduced? (shell game?) Are the gasses really adding to climate change?
What about China, Russia, and Iran? Do these countries care about the environment?
Atmosphere and Ocean - 7
There are three ways that heat travels on earth.
conduction: heat moves from direct contact between two or
more objects; things touching
radiation: heat moves with no contact between objects; pure
energy; sunlight to earth
convection: heat is carried between objects by a medium - liquid
or gas; heater/fan; boiling water, wind, magma
Most energy on earth travels
in convection currents. A
convection current is a moving
wave of liquid (water) or gas (air)
caused by heat spreading
molecules apart. Heat energy
causes a liquid or gas to rise
because it gets lighter. As the heat is slowly lost, the
molecules get cooler and heavier and sink. This movement
causes currents.
All winds on earth are convection currents. They move
vertically (up and down) when warm low pressure
(lighter/less dense) air rises and cooler high pressure
(heavier/more dense) air sinks. Winds move horizontally (side
to side) because of the earth’s rotation. Winds are always
described by the direction they come from.
Convection cells are large bodies of moving air. They are
global wind patterns that are named for the direction they
come from.
Atmosphere and Ocean - 8
The Coriolis Effect is the cause of worldwide wind
patterns in which winds are deflected and move to the
right in the northern hemisphere and move to the left in
the southern hemisphere. The Coriolis Effect is caused
by the earth’s rotation. Cool air from the polar regions
sink down while warm air from the equator rises. The
rotation causes the winds to be deflected.
Six distinct global wind patterns are formed from
the Coriolis effect- three on each hemisphere.
polar easterlies (60° to
90°latitude)
westerlies (30° to 60°
latitude)
east trade winds (0° to
30° latitude)
Atmosphere and Ocean - 9
The horse latitudes are at 30° latitude in both
hemispheres. Because it is the area between
convection cells, there is no horizontal wind here.
Winds sink straight down. The doldrums are at the
equator - 0°. Because it is the area between convection
cells, there is no horizontal wind here. Winds rise
straight up.
Jet streams are often called rivers of air. They are
narrow bands of strong wind found at the top of the
troposphere. Their paths typically have a meandering
or winding shape. The width of a jet stream is typically
a few hundred miles and its vertical thickness often less
than three miles. Jet
stream winds usually have a
speed of 150 to 300 miles per
hour, but speeds up to 450
miles per hour have been
recorded. In the northern
hemisphere jet stream winds
blow from west to east but
the flow often shifts to the
north and south.
Atmosphere and Ocean – 10
The location of jet streams shift throughout the
year and they are said to "follow the sun" since they
move north with warm weather and south with cold
weather. Jet streams are also stronger in the winter
because there is a large contrast between colliding
arctic and tropical air masses. In the summer, the
temperature difference is less extreme between the air
masses and the jet stream is weaker.
One of the most important impacts of the jet
stream is the weather it brings. Because it is a strong
current of rapidly moving air, it has the ability to push
weather patterns around the world. As a result, most
weather systems do not just sit over an area, but they
are instead moved forward with the jet stream. The
position and strength of the jet stream then helps
meteorologists forecast future weather events. In
addition, they are important to air travel because flying
in or out of them can reduce flight time and fuel
consumption. One future benefit of jet streams could
be to power airborne wind turbines.
Atmosphere and Ocean – 11
Two main jet streams affect weather in North America.
polar jet stream: between 23,000 to 39,000
feet above the ground; located between 30° to
60° north latitude; has the
strongest winds
subtropical jet stream: between 33,000
to 52,000 feet above the ground; located at 30°
north latitude; has lower wind speeds
El Nino is a climate event where a tropical South
Pacific ocean current found around the equator and
countries of Peru
and Chile warms a
few degrees. It is
a convection
current, not a
storm. It is one of
the largest factors
in global weather.
Spanish – the boy
Atmosphere and Ocean - 12
An El Nino cycle lasts about one calendar year and
occurs about every 3 to 7 years, but they are beginning
to happen more often. El Nino cycles predate human
industrial activity. During an event cycle, ocean
temperatures rise a couple degree causing sea levels to
rise. Heated water means more precipitation. Global
wind patterns are affected - trade winds are weakened
and even reversed. El Nino cycles disrupt the jet
stream in North America causing unusual weather. El
Nino cycles are responsible for monsoons (heavy rain
seasons) in the far East and droughts in Africa.
Spanish – the girl
La Nina is the normal condition where the South
Pacific ocean is cool. The change from El Nino to La
Nina is called the southern oscillation or ENSO.
“It is believed that El
Niño conditions
suppress the
development of
tropical storms and
hurricanes in the
Atlantic; and that La
Niña (cold
conditions in the
equatorial Pacific)
favor hurricane
formation.”
http://www.pmel.noaa.gov/tao/
elnino/faq.html#hurricanes
Atmosphere and Ocean - 13
The Gulf Stream is a strong, fast moving, warm
ocean current that originates in the Gulf of Mexico and
flows into the Atlantic Ocean. It is generally contains
very warm, deep, and narrow currents that carry water
from the tropics to the
poles. The Gulf Stream
was first discovered in
1513 by the Spanish
explorer Juan Ponce de
Leon and was then used
extensively by Spanish
ships as they travelled from
the Caribbean to Spain. In
1786, Benjamin Franklin
mapped the current, further
increasing its usage.
The Gulf Stream, like all
other ocean currents is
mainly caused by wind as it creates friction when moving
over the water. This friction then forces the water to
move in the same direction. The Gulf Stream is
typically 62 mi wide and 2,600 ft to 3,900 ft deep. The
maximum speed is about 5.6 mph.
gyre: ocean area surrounded by ocean currents
Sargasso Sea: North Atlantic gyre; 700 miles wide by 2,000 miles; ocean desert; no current
Atmosphere and Ocean - 14
Because ocean currents circulate water of
different temperatures all over the globe, they often
have a significant impact on the world’s climate and
weather patterns. The Gulf Stream gathers all of its
water from the warm tropical waters of the Caribbean
and the Gulf of Mexico causing the areas around it to be
warm. Florida and much of the Southeastern United
States is mild all year round because of the Gulf Stream.
The greatest impact the Gulf Stream has on climate
is found in Europe.
Since it flows into the
North Atlantic
Current, it helps keep
places like Great
Britain much warmer
than it would
otherwise be. This
place is also known for
its foggy, overcast conditions due to the Gulf Stream.
The Gulf Stream and its warm winds are also responsible
for keeping northern Norway’s coast free of ice and
snow.
Atmosphere and Ocean - 15
The Gulf Stream’s warm sea surface temperatures also
aid in the formation and strengthening of many of the
hurricanes that move through the Gulf of Mexico.
Additionally, the Gulf Stream is important to the
distribution of wildlife in the Atlantic. The waters off
of Nantucket,
Massachusetts are
incredibly biodiverse
because the
presence of the Gulf
Stream makes it the
northern limit for
southern species
varieties and the
southern limit for
northern species.
The stratosphere is about 20 miles thick. It starts
at about 10 miles or 60,000 feet above the ground and
goes to about 30 miles or 160,000 ft above the ground.
Temperatures start to increase through this layer.
They start at about -76°F and increase to about 40°F in
the stratopause (top part). The stratosphere has very
thin air made mostly of oxygen.
Atmosphere and Ocean - 16
From the middle to the top of the
stratosphere is the ozone layer. The
reason the sky looks blue is because of the
ozone layer. Ozone is a poisonous bluish
gas with a strong odor. It is a molecule
made of three oxygen atoms (O3). The
ozone layer acts like a shield that absorbs
the sun’s ultraviolet (UV) energy which is
destructive to life and causes cancer.
UV hits O3 breaking it into O2 and O
UV hits the O2 and O and combines them again into O3
When ozone is produced on the ground from cars and
factories, it is harmful and forms smog. Pollutant such as
chlorofluorocarbons (CFC’s) from factories, refrigerators, and
air conditioners rise
through the atmosphere.
The chlorine in the CFC
molecule attacks the ozone
molecule destroying it.
When the molecules in the
ozone layer are broken
apart (from above by the
sun and below by pollution),
the layer is thinned allowing
more harmful UV rays to
reach the earth.
Atmosphere and Ocean - 17
Thin areas in the ozone layer are sometimes called
holes. The ozone layer is thinnest over the equator, the
poles, and major metropolitan areas (cities). If left
alone the ozone layer will spread out and fill in the thin
spots.
It’s up to us to be educated and protect our wonderful
planet!