Transcript Weather & Climate

Weather
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Temporary behavior of atmosphere
(what’s going on at any certain time)
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Small geographic area
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Can change rapidly
Weather
--The study of weather is
meteorology
--Someone who studies weather
is called a meteorologist
Climate

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Long-term behavior of atmosphere
(100+ years)
Large geographic area
Very slow to change
Climate Zones
The Earth’s climate can be divided
into general climate zones according
to average temperatures. The three
major climate zones on the Earth are
the polar, temperate, and tropical
zones.
POLAR
90o -60o latitude
Cool summers, cold year-round
Dry
POLAR
In each hemisphere, the polar zone
extends from the pole to about 60 degrees
latitude. In polar zones, the average
yearly temperature is below freezing.
There are some areas in the polar zones,
such as the northern coasts of Canada and
Alaska and the southern tip of South
America, where the snow melts during the
warmest part of the year.
TEMPERATE
60o-30o latitude
True Seasons
Variety of climate patterns
Moderate precipitation
(rain/snow)
TEMPERATE
In each hemisphere, the temperate zone is
found between 60 degrees and 30 degrees
latitude. In the areas of the temperate zones
farther from the equator, snow is common in
the winter. In the areas of the temperate
zones closer to the equator, rain normally falls
all year round. The average amount of
precipitation is about the same throughout.
The average temperatures range from 5 ° C to
20 ° C.
TROPICAL
30o - equator
No winter, warm year-round
High temp, rainfall, humidity
TROPICAL
The tropical zones, which extend from 30
degrees north and south latitude to the
equator, have high temperatures and high
humidity. Tropical zones are also known as lowlatitude climates. The average temperature
during the coldest month of the year does not
fall below 18 ° C.
Climate Elements
These include temperature, humidity,
precipitation, pressure and winds.
Climate Controls (PSALMON)
Prevailing winds
Slope or aspect of the land
Altitude
Latitude
Mountain barriers
Ocean currents
Nearness to large bodies of water
Prevailing Winds
More moisture is present in air blowing
over the sea, and precipitation is likely if
prevailing winds blow from water to land.
The opposite effect occurs as air blows
from land to sea. The air becomes warm
and dry or cold and dry depending on the
time of year.
Slope AKA Aspect
The amount of solar radiation received on the
earth’s surface will vary according to the slope or
aspect of the land. For example, a north facing will
receive less solar radiation than a south-facing
slope in the northern hemisphere. That is why you
often find moss growing on north facing roofs of
houses.
Altitude
Elevation, or altitude, is the distance above sea
level. As elevation increases, the air becomes less
dense. Less- dense air cannot hold as much heat as
denser air.
So the higher the altitude in the atmosphere, the
lower the temperature. The climate on tops of
mountains will vary from climates of valleys. Snow
can be found on mountaintops near the equator
because of the effect of altitude.
Latitude
Latitude is the measure of the distance north and
south of the equator. Latitude is measured in
degrees. Areas close to the equator, or 0 degrees
latitude, receive the direct rays of the sun. These
direct rays provide the most radiant energy.
Areas near the equator have a warm climate. Polar
regions have a cold climate.
Mountain Barriers
The amount of precipitation at a particular
location is also affected by mountain
ranges. A mountain range acts as a barrier
to prevailing winds. The windward side of a
mountain has a wet climate. On the
leeward side, relatively dry air moves down
the side of the mountain and results in
very little precipitation. Chinooks are
examples of mountain barrier affects on
climate.
Ocean Currents
Ocean currents affect the temperature of
the land they pass by
Cold ocean currents = cooling effect
Warm ocean currents = warming effect
Temperature changes affect pressure –
which then creates WINDS
Winds blow this cooling or warming effect
over the land
Ocean Currents
Some short-term changes may be the result of
changes in ocean currents and global winds. Ocean
currents help transfer heat to the atmosphere.
This process generates global winds. The global
winds help move ocean currents. Any major
change in an ocean current can cause a change in
climate. El Nino is an example.
Nearness to Water
The climate of a region can be affected according
to its proximity to large bodies of water. Water
and land cool at different rates. Water retains
more heat than does land in the winter months and
this is the reason why Vancouver’s climate is mild
and wet as compared to the prairie region where
land tends to cool more quickly. During the summer
months land heats up more quickly than does
water. Regions located away from large bodies of
water also experience greater temperature
ranges.