Transcript Atmospheric Pressure

1. How many inches of rain does Manitou Springs receive in
May?
2. What is the highest average temperature?
3. Is there more precipitation in the winter or summer months?
Weather and Climate
The Atmosphere
• Review:
– Earth’s atmosphere is the envelope of gases
that surround the Earth.
Weather and Climate
• Weather – condition of the atmosphere at
a given time and place
• Climate – weather conditions in a
geographic region over a long period of
time
Weather and Climate
• What is San Antonio’s weather like today?
• What is the climate of San Antonio?
Solar Energy
Factors that affect climate:
The Sun
– The sun’s energy reaches earth
– Half of the energy is reflected back into space
or absorbed by the atmosphere
– The other half is absorbed by the Earth’s
surface and converted into heat energy
– The atmosphere traps this heat in a process
called the greenhouse effect
– The greenhouse effect helps keep the planet
warm
The Greenhouse Effect
Global Warming
• Global warming – process by which the
Earth grows warmer over a period of time
• Human caused or natural cycle of the
Earth?
Global Warming
• Carbon dioxide is a greenhouse gas…
• Because it absorbs heat, more carbon
dioxide could enhance the greenhouse
effect
Global Warming
• Human activities such
as burning coal,
natural gas, and oil put
more carbon dioxide
into the atmosphere
Global Warming
• What are some things that people are
doing to help stop global warming?
Weather and Climate
• We have seen that the sun affects weather
and climate.
• The air around you also affects what the
weather and climate will be like…
Factors that affect climate:
Atmospheric Pressure
• the air in our atmosphere has weight
• air around you is pushing on you
Atmospheric Pressure
• High Pressure
– Cold air; dense, therefore it sinks
– As it sinks, the air heats and dries
– Usually brings stable, clear and dry weather
– can equal extreme heat and bitter cold
(Think about a hot summer day here in San
Antonio)
H
Clear Day
Atmospheric Pressure
• Low Pressure
• when air is heated, it expands, becomes
less dense, and rises
• The water vapor the air carries may
become clouds
• Brings unstable weather
Atmospheric Pressure
• Effects on weather can vary in intensity:
slight breezes and cloud cover to powerful
storms w/ heavy rain and high winds
L
Factors that affect climate:
Global Wind Belts
• Air pressure affects global wind patterns
• wind always flows from high to low
pressure
Winds
• prevailing winds – winds that blow from
the same direction most of the time
• doldrums – areas with no prevailing
winds (area has little wind = problems for
sailing ships)
Winds
• In the middle latitudes, the prevailing
winds are called westerlies (flow from
west to east)
• In the contiguous U.S. , these winds
carry most weather patterns and storms
from the west to the east
• Contiguous – connecting or bordering
• “You have won a trip to anywhere in the
contiguous United States!”
• What places are excluded from this prize?
Pressure and Wind Systems
Earth’s Energy Balance: Winds
Think of Earth as a living organism, always
trying to reach a balance
*winds move heat and cold across the
earth’s surface
Factors that Affect Climate:
Oceans
Ocean Influence
Water heats and
cools more slowly
than land, making
coastal areas milder
than inland areas
Kansas City has much colder winters and
much warmer summers than San
Francisco.
Factors that affect climate:
Ocean Currents
• Ocean Currents – rivers of seawater
that flow in a circular path
–Created by Earth’s winds, rotation,
and the temperatures of the water
Ocean Currents
Help maintain Earth’s
energy balance
How?
• Moves heat back and forth
between the tropics and
the polar regions
• Warm currents carry heated water
from the tropics toward the cooler
middle latitudes
Gulf Stream
Warm current off the coast of Florida
flowing north to Europe
Gulf Stream
• What North American country is along
the same latitudes as Western
Europe?
• Without the Gulf Stream,
temperatures in Western Europe
would be lower
Gulf Stream
• Some scientists fear
that Global Warming
could ultimately lead to
the shutdown of the
Gulf Stream
• Melting ice may stop
the circular flow of the
water
= Europe will be in a mini
ice-age
California Current
• Cool current
• Southward flowing off the west coast of
the U.S. that cools the land nearby
California Current
Factors that affect climate:
Mountains
Elevation
• Elevation – height on Earth’s surface
above sea level
• An increase in elevation causes a
drop in temperature
–Drops 3.5 degrees F per 1,000 ft
• Can there be snow in places that
are on the equator?
Snow on the Equator
Snow near the equator
Mountains influence climates by…
• Orographic effect
–Moist air pushes against a
mountain
–The air is forced to rise
–This creates clouds and causes
precipitation
Orographic Effect
Orographic Effect
Windward side: side of mountain facing the
wind
Orographic Effect
• Leeward side: side of mountain facing
away from the wind
• Leeward side is called a rain
shadow.
Let’s review
• Factors that affect climate:
– Sun and latitude
– Atmospheric Pressure
– Global Wind Belts
– Ocean (closeness to water and ocean
currents)
– Mountains
Warm-up:
1. What is the name of the prevailing
winds in the mid-latitudes?
2. Why do coastal areas have a milder
climate than inland areas?
3. What keeps Europe from being much
colder than it is?
• 1. What is the name of the prevailing winds in the midlatitudes?
• 2. How does the wind affect the Earth’s energy balance?
• 3. Why do coastal areas have a milder climate than
inland areas?
• 4. What keeps Europe from being much colder than it is?
• 5. Which side of a mountain is the dry or desert side?
The Greenhouse Effect
• The Greenhouse Effect is needed
= keeps the Earth warm
* Greenhouse gases = carbon dioxide,
methane, water vapor, and nitrous oxide
1. What is the temperature in Nome, Alaska compared to San Antonio, Texas?
2. What factor is causing this difference?
3. What part of the country is currently experiencing the greatest amount of
heat?
4. What type of front extends across Florida?
Assignment
• Read the article: “Shading the Earth”
• Write a paragraph (7-10 sentences) about
the following statement: What could be
potential problems of creating a "sun
shield"?
• Ideas to get you started may include cost
and who pays for it....
El Niño and La Niña
• El Niño—Ocean and weather pattern in
which the southeastern Pacific Ocean is
warmer than usual, affecting regional
climates
• La Niña—An ocean and weather pattern
that causes the eastern Pacific Ocean to
be colder than normal
Normal
El Niño
El Niño: Cause and Effect
• Cause:
– Change in the ocean’s surface temperature
• Effect:
– Changes in weather patterns around the
world
Cause and Effect
• Cause:
– Atmospheric pressure north of Australia rises
• Effect:
– Trade winds weaken
Cause and Effect
• Cause:
– Trade winds weaken
• Effect:
– Warm water flows eastward
Cause and Effect
• Cause:
– Warm water flows eastward, over the cooler,
nutrient-rich waters off the Peruvian coast.
• Effect:
– Sea life suffers from lack of nutrients,
fishermen cannot catch any fish.
1. How many inches of rain does Manitou Springs receive in
May?
2. What is the highest average temperature?
3. Is there more precipitation in the winter or summer months?
Happy
Constitution
Day!
Write the
Preamble to the
Constitution on
your warm-up
sheet
“We the people..”
Preamble to the Constitution:
“We the People of the United States, in Order to
form a more perfect Union, establish Justice,
insure domestic Tranquility, provide for the
common defense, promote the general Welfare,
and secure the Blessings of Liberty to ourselves
and our Posterity, do ordain and establish this
Constitution for the United States of America.”
Declaration of Independence
"We hold these Truths to be self-evident, that all
Men are created equal, that they are endowed
by their Creator with certain unalienable Rights,
that among these are Life, Liberty and the
Pursuit of Happiness--That to secure these
Rights, Governments are instituted among Men,
deriving their just Powers from the Consent of
the Governed."
Too Late to Apologize