Transcript Climate Controls

Climate Controls
What is the Difference Between
Climate and Weather?
• Weather is the combination of
temperature, precipitation, cloud cover,
winds, relative humidity, and air pressure
as they are experienced on a DAILY basis.
• Climate refers to the weather conditions of
a place averaged over a 30 year period.
The main elements of climate are
temperature and precipitation.
Climate Descriptors
Average Annual Temperatures
• Very Hot
Above 25 °C
• Hot
18°C to 24 °C
• Warm
10°C to 17°C
• Cool
0°C to 9°C
• Cold
-10°C to -1°C
• Very Cold
-11°C or colder
Climate Descriptors
Total Annual Precipitation
• Very Low/ Very Dry
Below 250 mm
• Low/ Dry
251 mm to 500 mm
• Medium / Average
501mm to 1000mm
• High/ Wet
Over 1001 mm
If the temperature graph dips in the middle, then the city must be in
the southern hemisphere.
SOUTHERN HEMISPHERE
If the temperature graph is flat, then the city must be near the
equator. The flatter the graph, the closer it is to the equator.
If there is about the same amount of precipitation in each month,
the city is probably near water (maritime). Singapore is near the
South China Sea.
EQUATORIAL
If the temperature graph rises in the middle, then the city must be in
the northern hemisphere.
This is a graph of the city on London. You can tell that it is near the
water, because the rain is high all year.
NORTHERN HEMISPHERE
Maritime and Continental
• A MARITIME city is one that is near a
large body of water, like an ocean.
– Lots of precipitation
– Not a lot of difference between summer and
winter temperatures
• A CONTINENTAL city is one that is far
inland – there is not a lot of water around
it.
– Not as much precipitation; varies by season
– Wide temperature difference between
summer and winter
Climatic Controls
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Latitude
Altitude
Mountain Barriers
Land and Water Surfaces
Ocean Currents
Air Masses
Pressure Cells
Pollution
1. LATITUDE
General:
• As you go north or south of the equator
the temperature will get colder and the
precipitation will be drier
• Latitude is the single most important
influence on climate
LATITUDE
Why?
• The same amount of energy hits the Earth,
but as you go farther north or south of the
equator, the Earth curves, so the same
energy has to hit a larger area. Therefore
the energy to the north and south is less
and the energy at the equator is more.
Earth
Sun
Less land to cover at the equator –
more surface area at the poles
Sun
Earth
The same amount of
energy comes from the
sun.
LATITUDE
Specifics:
• Equator (tropics) 0 - 30°N and 0 - 30°S very hot
temperatures with no seasons
• Mid – Latitudes 30°N to 60° N and 30° S to 60°
S summers range from long and hot near 30° to
cool and short near 60°
• Arctic 60° N to 90°N and 60°S 90°S summers
will be short and cool, winters will be very, very,
very, very long and very, very, very, very cold
2. Altitude
General
• The higher up you go, the colder it gets
Altitude
Why?
• At the Earth’s surface the molecules of air are
packed tightly together, so they bump into each
other all the time. This “bumping” creates
friction which makes heat.
• As you go higher, the molecules spread out
more, so there is less and less “bumping”. This
means there is also less friction, so there is less
heat.
Altitude
Specifics
• The ENVIRONMENTAL LAPSE RATE is
the rate at which temperature goes down
as altitude increases.
• In dry areas the ELR is 10ºC/ 1000m
• In wet areas the ELR is 6.4ºC/ 1000m
3. Mountain Barriers
General
• Mountains affect the precipitation and the
wind patterns of the land around them.
Mountain Barriers
Why?
Precipitation
Condensation
Chinook
Mountain Barriers
• As the wind hits the mountain, it can only
go up and over, or around the barrier. If
there is a valley opening, the wind most
often will redirect itself there. This means
that the wind going into the valley will be
very strong.
4. Land and Water Surfaces
General
• Land near large bodies of water have
more even temperatures throughout the
year than land in the middle of the
continent.
Land and Water Surfaces
Why?
• During the day and in summer, water stores heat
from the sun as LATENT HEAT
• In cooler temperatures (night or winter), the heat
is gradually released
• On land, the sun’s heat is quickly absorbed, but
quickly released, so there is a big difference
between day and night temperatures, or summer
and winter temperatures
Land and Water Surfaces
SOLAR ENERGY
MUCH
REFLECTED
ENERGY
WARMER
SOLAR ENERGY
LITTLE
REFLECTED
ENERGY
COOLER AIR
AIR
LATENT HEAT
Land and Water Surfaces
Specifics:
• Maritime areas have cooler summers and
warmer winters (less TEMPERATURE
VARIATION). They also usually have
more precipitation.
• Continental (inland) areas have warmer
summers and colder winters (higher
temperature variation). They also usually
have less precipitation.
5. Ocean Currents
General
• An ocean current is a large amount of
ocean water moving in one direction.
• Warm currents start nearer the equator
and flow either north or south.
• Cold currents start farther north or south
and flow toward the equator.
Ocean Currents
General
• Warm currents usually provide warmer
temperatures and more precipitation.
• Cold currents usually provide cooler
temperatures and less precipitation.
Ocean Currents
Why?
• Air above a warm current is warm
• Air above a cold current is cool
• Warm air can hold a lot of moisture
• Cool air can only hold a little moisture
Ocean Currents
Why?
• When the warm water flows into the cold
water the water starts to evaporate
quickly.
• The air above the cold water is cool so the
evaporated air quickly condenses and
precipitates
Ocean Currents
Why?
• When the cold current moves into warm
water, the air above it is warm, so it can
absorb the water that evaporates without
precipitating
Ocean Currents
6. Air Masses
General
• Air masses are huge bodies of air that
contain similar weather.
• Air masses are described by where they
come from.
• The names of the masses give you some
idea of what the mass is like.
Air Masses
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mP – Maritime Polar – Moist and Cold
mT – Maritime Tropical – Moist and Warm
cA – Continental Arctic – Dry and Cold
cP – Continental Polar – Dry and Very
Cold
• cT – Continental Tropical – Dry and Hot
Air Masses
Why?
• When air masses meet, a FRONT is
created.
• We name the front for the temperature of
the advancing air mass.
• A Warm Front would be an air mass with a
higher temperature overtaking an air mass
with a lower temperature.
Air Masses
Specifics:
• When the warm front occurs, the warm air
is forced up over the cold air it has caught
up to.
• The result is very widespread heavy cloud
cover and often, light rain.
Air Masses
Specifics:
• When a cold front occurs, the cold air
forces the warm air it has caught up to
upward very quickly.
• Because the air is forced up so quickly is
causes towering CUMULUS CLOUDS and
heavy storms.
7. Pressure Cells
General
• Low pressure cells are columns of air that
are created when warm air rises.
• The low pressure is caused by the air
leaving the space.
• High pressure cells are columns of air that
are created when cool air sinks.
• The high pressure is caused by more air
coming into the space.
Pressure Cells
Low Pressure Cells
• As the warm air rises, it cools causing
condensation. This condensation makes
clouds which may precipitate.
• Low pressure cells are linked to
precipitation, storms, and when combined
with strong winds, tornadoes.
• This type of precipitation is called
CONVECTION PRECIPITATION
Pressure Cells
High Pressure Cells
• As the cool air sinks, it warms up, so it can
hold more moisture.
• So there is very little precipitation.
• High pressure cells are linked to clear,
calm weather.
8. Air Pollution
Greenhouse Effect
• As our world becomes more INDUSTRIAL
and more populated, we produce more
carbon dioxide and other gases.
• These gases trap the sun’s heat energy
within the atmosphere, causing the
temperature to increase.
• As the level of gases continues to rise, the
temperature of the earth will also rise.
Air Pollution
The weakening of the Ozone Layer
• Ozone is a gas that is similar to oxygen (O²), but
contains three, not two molecules of oxygen
(O³).
• Ozone forms a protective barrier around the
earth, keeping harmful UV rays from entering
our atmosphere.
• As pollutants break down the ozone into oxygen
this layer is thinned and even has a hole in it.
• The result of the loss of the ozone layer will be
to threaten all life on Earth.
Analysis Chart
What makes a climate hot?
What makes a climate cold?
• Latitude
• Latitude
– Closer to the equator
• Altitude
– Lower altitude (elevation)
• Mountain Barriers
– No effect
• Land and Water Surfaces
– Further inland
• Ocean Currents
– Near a warm current
• Air Masses
– Tropical
– Closer to the poles
• Altitude
– Higher altitude (elevation)
• Mountain Barriers
– No effect
• Land and Water Surfaces
– Near water
• Ocean Currents
– Near a cold current
• Air Masses
– Arctic/Polar
Analysis Chart
What makes a climate wet?
What makes a climate dry?
• Latitude
• Latitude
– Closer to the equator
• Altitude
– No effect
– Closer to the poles
• Altitude
– No effect
• Mountain Barriers
• Mountain Barriers
– Windward side
– Leeward side
• Land and Water Surfaces
– Near water
• Ocean Currents
– Near a warm current
• Air Masses
– maritime
• Land and Water Surfaces
– Farther inland
• Ocean Currents
– Near a cold current
• Air Masses
– continental