Geography 12
Weather and Climate
Big Idea: What creates the
climate of an area?
We will do some work on climate controls,
discuss weather, and then return to climate
zones of the world
Here is what you will learn
today:
• Climate is what you can expect the weather to be
like over a long period of time
• There are several things that determine what the
climate will be:
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How far is the place from the equator?
What season is it – is the area tilted away from the sun?
Are there warm or cold ocean currents nearby?
What is the altitude (metres above sea level)?
Is it on or near a large body of water, like the ocean?
Connected to this is – is it inland (continental or maritime)
What are the prevailing winds in the area?
WALPOC
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•
•
•
•
•
Water
Altitude
Latitude
Prevailing winds
Ocean Currents
Contintentality
• Another way to
remember this is to
use the mnemonic,
WALPOC
Let’s go over them
one by one
Idea to understand:
What is the difference
between weather and
climate?
Weather
Weather tells you
what to wear on a
daily basis
• Weather is day-today
• What is happening
at any moment
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–
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–
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Sun
Rain
Wind
Snow
Fog
cloud
Will I need
my toque
today?
http://www.bluenose2.ns.ca/Catalogue/Clothing/
OhCanadaLongToque.html
Climate
• Climate is what is
normally expected in a
place year after year
http://www.circlearanchhostel.com/recgal.html
http://www.brazadv.com/brazil_tours/montane_rainforest.htm
• What weather would
you expect day after
day in these two
places and why?
Climate and Seasons
• In the pictures on the previous slide, we
looked at two places where the weather is
the same all year long – the desert, and the
rainforest. Very little changes, month to
month
• In other places, like Vancouver, we have a
climate that changes with every season
• Think about why we have seasons, while
other places do not… more on this in a
moment
• What is interesting about all this is that there
are many different things that impact what
the climate is in a place
Idea: The difference between
climate and weather
What kinds of questions would we ask?
• Climate!
– How much precipitation
do we usually get in a
year – can we farm
here?
– How should we build this
house – does it need a
strong roof to carry a lot
of snow?
– Are there four seasons
(spring, summer, winter
and fall?) in this area?
– Can our town have a ski
hill?
• Weather!
– What should I wear
today?
– What will the roads be
like today or tomorrow?
– Is it going to rain when
we go camping this
weekend?
– Do I need to wear my
coat?
The world has several climate zones
or areas. This PowerPoint is about
WHY that is.
http://en.wikibooks.org/wiki/Basic_Geography/Climate/Global_Climate
Why are there different climates
in different parts of the world?
• Water
• Altitude
• Latitude
• Prevailing winds
• Ocean Currents
• Contintentality
1. Climate Control: Latitude
Look at this globe
• You can see that the earth is
titled a bit on its side (on its axis
– which is an imaginary line
through the middle of the
planet)
•Axis
•Go to:
•http://highered.mcgrawhill.com/sites/0072482621/stud
ent_view0/animations.html#
•Click on Chapter 8 Animations, “Earth’s
Rotation Axis”
•If you have earphones you can listen to
the audio of the link mentioned above
•Go To:
•http://esminfo.prenhall.com/science/
geoanimations/animations/01_Earth
Sun_E2.html
The Earth’s tilt on its axis
• You can see that the northern part of
the world - where we live - spends
LONG HOURS in the sun at the
beginning of the clip (summer), but
only gets a VERY FEW hours once it is
tipped away from the sun (winter)
• Notice that the equator gets about 12
hours of sun ALL YEAR ROUND, so they
don’t have seasons like ours
Where on Earth are we?
We live way up
here, north of the
equator. We have
long days in the
summer and short
days in the winter.
We have four very
distinct seasons
because of our
latitude.
http://www.jupiterimages.com/itemDetail.aspx?itemID=23501499
This is the
equator – no
real seasons
in most areas:
12 hours of
daylight all
year.
Length of time a place is
exposed to the sun
• The north and south
of the planet are
exposed the sun for
fewer months of the
year
• The less sun, the
colder it is
Climate Control: Latitude
Less time in the sun, but also, less strength in
the sun
Equator
Key term: Insolation: amount of
sun received at the earth’s surface
•There is another important
idea about latitude as a
control
•Because the earth is round,
and titled, the sun’s rays hit
the earth at different angles
•So, you can see that at the
equator, the sun comes
straight in and heats the
area more strongly
•North and south of the
equator, the rays are spread
out and less strong
Here’s another picture to show how
important the idea of latitude is to
climate
• See that the same
amount of sun is
coming in, but the
sun is much more
concentrated or
strong in the first
example
• MUCH WARMER!!
2. Climate Control: Altitude
• Altitude – how high
above sea level
the land is
• This mountain is
located in the Alps
• Why is there snow
here…
• But not here?
Answer: Usually, air cools as it rises
• The higher the mountain, the cooler the temperature at
the top
• In general, for every 150 metres of rise in altitude, the
temperature drops 1 degree Celsius – the air becomes
thinner and less able to hold onto heat
• Sometimes, an inversion occurs and it is warmer on the
mountain than in the valley – like happens at our ski hill
once in a while
•
http://staffwww.fullcoll.edu/tmorris/elements_of_ecology/chapter_3.htm
Glaciers at the equator?
• This is a picture of a
glacier located on
Mount Kenya, in Kenya
Africa
• It is located just south of
the equator
• Why is it a surprise to find
a glacier at the equator?
• What does it tell you
about how altitude can
change the climate of
an area?
• The glaciers on this
mountain are
disappearing. What
would cause this?
3. Climate Control: Ocean
Currents
• Think about the idea that some ocean
currents are warm and some are cold.
What climate would you expect on a coast
with warm water? What climate would you
expect with cold water currents?
• Go to this link and look at ocean currents in
the world.
– Find Chapter 24: Examine Global Surface
Currents and click on it to watch
• http://www.classzone.com/books/earth_sci
ence/terc/navigation/visualization.cfm
– When you put your cursor over the map, it shows
how the wind blows. Does the wind have
anything to do with the direction of the ocean
currents?
Here’s another look
http://scripts.mit.edu/~gmaze/blog/
Where are most of the cold currents? Where are most of the warm currents?
Why do you think it is this way?
Animation
• On the previous map, locate the Gulf
Stream Current and the Labrador
Current
• Follow this link to see them in action –
When you get there, look for The Gulf
Stream animation
• http://homepages.ge.ucl.ac.uk/~awa
yne/polar/climate.html
This is a cool way to look at
ocean currents
http://blue.utb.edu/paullgj/geog3333/lectures/physgeog.html
Use what you know:
http://scripts.mit.edu/~gmaze/blog/
• Based on the information on this map and on
the animation you watched, why is London,
England a warmer place to live than St.
John’s Newfoundland, Canada?
4. Climate Control: Distance
from the Sea
• The climate of an area will be different if it is
located beside the ocean, or inland, away
from any large body of water
• Think about what you know about the
climate in the Yukon. What is it like there?
• Think about what you know about the
weather here in Vancouver, which is pretty
far from the ocean. How are they different?
• Key Terms: maritime climate and
continental climate
Climate Control: How close to
the ocean?
• Places that are near water usually
have a lot more rain or snow than
places inland – especially if the ocean
current is warm
• The warm moist air blows in off the
ocean and drops its moisture on the
land in the form of rain and snow
The climate of places on the
ocean are usually milder than
inland
• Mild means not that hot, and not that cold!
• Places like Vancouver or Victoria that are on
or near water, will be WARMER in winter
(NOT AS COLD), and COLDER(NOT AS HOT)
in summer.
• Hmmmmm????
• Why is that? Take a look at the next slide
There are two ideas here that
are important!
•Water takes a long time to
warm up, but water cools
down very slowly
•Land warms up quickly, and
also land cools quickly
Summer
The ocean
heats up
slowly, so
summer
temperatures
on the ocean
are much
cooler during
the summer,
as cool
ocean wind
blows in.
North America
The land
heats up
fast, so
summer
temperatures
away from
the ocean
are hot,
HOT!
Winter
The ocean
cools down
very slowly,
so the air
over it is
warm, and
this warm air
blows into
the colder
land,
keeping
coastal
areas
warmer in
winter.
The land
cools down
quickly, so
winter
temperatures
inland are
COLD!
North America
Use what you know:
• Why would it be
very hot in the
Prairies (Alberta,
Saskatchewan) in
the summer?
Prevailing Winds
• Air pressure and winds (caused by air
pressure)
• We will take a longer look at this, and why it
happens, but for now:
• Winds off a warm ocean will bring rain
• Winds coming from the Arctic will be dry
and cold
• Prevailing means the winds you can expect
over the long term, so they can impact the
kind of climate you expect in a certain
place
• Prevailing
winds of
the earth –
more on
this to
come
To sum up, or review:
• Climate is what you can expect the
weather to be like over a long period of
time
• There are several things that determine what
the climate will be:
– How far is the place from the equator?
– What season is it – is the area tilted away from
the sun?
– Are there warm or cold ocean currents nearby?
– What is the altitude (metres above sea level)?
– Is it on or near a large body of water, like the
ocean?
– What are the prevailing winds?