Geography 12Weather 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

Created by Ms. Inden

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:– 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

• 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 is day-to-day

• What is happening at any moment– Sun– Rain– Wind– Snow– Fog– cloud

Weather tells you what to wear on a

daily basis

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

• What weather would you expect day after day in these two places and why?http://www.circlearanchhostel.com/recgal.html

http://www.brazadv.com/brazil_tours/montane_rainforest.htm

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 Fort St. James, 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 betweenclimate 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: LatitudeLook 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.mcgraw-hill.com/sites/0072482621/student_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_EarthSun_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?

This is the equator – no real seasons

in most areas: 12 hours of daylight all

year.

We live way up here, far 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

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: LatitudeLess time in the sun, but also, less strength

in the sun

Equator

•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

Key term: Insolation: amount of sun received at the earth’s surface

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_science/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

Where are most of the cold currents? Where are most of the warm currents?

Why do you think it is this way?

http://scripts.mit.edu/~gmaze/blog/

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/~awayne/polar/climate.html

This is a cool way to look at ocean currents

http://blue.utb.edu/paullgj/geog3333/lectures/physgeog.html

• 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?

http://scripts.mit.edu/~gmaze/blog/Use what you know:

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 Vancouver. What is it like there?

• Think about what you know about the weather here in Fort St. James, 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

North America

Summer

The land heats up fast, so summer

temperatures away from the ocean are hot, HOT!

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

Winter

The land cools down quickly, so

winter temperatures

inland are COLD!

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.

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?