Transcript Weather and Climate

Weather and Climate
LET’S GET READY TO TREMBLE!
Before you learn anything else,
know this:
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Warm air rises. Cold air sinks.
Air masses are large volumes of air with
similar temperature and moisture.
Cold air masses (CAM) are heavier than
warm air masses (WAM).
WAM and CAM do not get along, and do not
like to be seen together. They’re funny like
that.
Weather vs. Climate: It’s about
time.
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What is weather?
Weather is what is happening in the atmosphere at a
specific time. For example, right now it is cloudy,
therefore the weather is cloudy. If it stops being
cloudy, the weather is no longer cloudy. Too easy.
Weather vs. Climate: It’s about
time.
Weather conditions normally involve measuring
conditions, temperature, atmospheric
pressure, windspeed, etc.
http://www.theweathernetwork.com/weather/citi
es/can/Pages/CANB0040.htm
Weather vs. Climate: It’s about
time.
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Climate is like a collection of weather.
Climate refers to the average condition of
temperature, precipitation, humidity,
pressure and wind in an area OVER TIME.
Weather vs. Climate: It’s about
time.
So what’s the difference?
Because weather is specific to time, it may not
be the same as climate. For example – the
climate of New Brunswick in January is cold
and dry. HOWEVER…it is not unheard of to
have a January day with weather above zero
degrees. By itself, this event does not affect
our climate.
Condensation
Warm air rises. Cold air sinks.
Condensation occurs when warm, moist air
rises, cools, and forms clouds.
But…how does that air get up there?
There are three main ways we will discuss.
Orographic Condensation
Orographic condensation occurs when warm,
moist air comes into contact with higher
ground.
WAM cools &
condenses
WAM moves
toward high
ground
Mount Oro
Frontal Condensation
Frontal condensation occurs when a warm,
moist air mass rises over a cold air mass.
The edge of these air masses are called
fronts.
Yo, man…why
you frontin’?
Convectional Condensation
Convectional condensation occurs when cooler
air is warmed and moistened from below.
Cool air moves over
a heat source and
becomes warm.
Wind
Wind
Warm air rises. Cold air sinks.
WAMs and CAMs do not get along. They do
not like to mix.
Wind in a high pressure system
Wind in
high
pressure
system
Wind in a high pressure
system is caused when a CAM
sits
on in
top of a WAM.
Wind
Because
cold is heavier than
low
warm,
it pushes it down, and
pressure
the
warm air moves out of its
system
way. This moving air is felt as
Oh no!
wind.
My
hat!
Wind in a low pressure system.
Wind in a low pressure
system takes place
when an large air mass
becomes warm and
rises from the ground.
Cooler air will rush in
from the side to take its
place. This cool air is
felt as wind.
Note-taking activity
In your text, please read and make notes on page 38 (Latitude, air
masses, Ocean Currents). You must identify the following:
• All 3 major air masses that affect our weather.
• Both Ocean Currents
• How fog is formed.
•
Questions: page 42, 1 a & b
You will be responsible for this information on tomorrow’s quiz.
Please look up the following
terms:
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Anemometer
Barometer
Barometric pressure
Beaufort wind scale
Check the glossary on this website:
www.theweathernetwork.com/inter/help/glossary/
Our 3 Major Air Masses
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Continental Arctic: Air mass from Northern
Canada in winter. It feels cold and dry.
Hint: think about our cold winter winds.
They make your skin feel dry.
Our 3 Major Air Masses
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Maritime Tropical: This is an air mass from
the Caribbean. It feels warm and moist.
Hint: think about the Caribbean sea. It is
warm, and humid / moist.
Our 3 Major Air Masses
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Maritime Polar: Blows in from the Atlantic
coast of Newfoundland. It feels cool and
moist.
Hint: well…no hint here yet. Just memorize
it.
Our Major Ocean Currents
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Ocean currents are very similar to air masses
in that they bring temperature and moisture
conditions to our area.
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Gulf Stream – a warm ocean current from the
south. It brings warmth to the Southeastern
parts of the Atlantic provinces.
Our Major Ocean Currents
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The Labrador Current: Comes from the
north and brings cold water to our region.
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The Gulf Stream warms and moistens the air
above it. The Labrador Current cools and
moistens it. This is important.
Fog
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Fog is formed in much the same way as
clouds. When the warm moist air from the
Gulf Stream, meets the cool moist air from
the Labrador Current, condensation occurs.
Because the warm air does not need to rise
to become cool, the ‘cloud’ is formed on the
ground. This is FOG!
Snow
 Snow
is formed when water
vapour condenses at a
temperature below the freezing
point.
Snow
When water vapour is warm,
the particles move very
quickly. As the warm air
rises, cools and condenses,
the particles slow down.
Snow
 If
the particles continue this
process below the freezing
point, the particles will slow to
the point that they freeze and
stick together. When enough of
these particles stick together,
they get heavy and fall as snow.
Proximity to Water – Questions to
Ponder
How would you describe the weather and
climate (temp and moisture) of
Fredericton in the winter?
Is this different in Saint John?
Does this change in the summer months?
Proximity to Water – Questions to
Ponder
Average temperature in Fredericton, NB:
Summer – (25 – 30)
Winter – (-12)
This creates an average temperature range of 42
degrees Celsius!
Proximity to Water – Questions to
Ponder
Average temperature in Saint John, NB:
Summer – (20 – 22)
Winter – (-7)
This creates an average temperature range of 29
degrees Celsius.
Proximity to Water – Questions to
Ponder
What is it about the physical location
of Saint John that creates this
difference in climate?
Proximity to Water
 Sunshine
heats land and water at
different rates. Water, and the air
over it, heats and cools more
slowly than land.
Proximity to Water
 As
a result, areas very close to
large bodies of water stay cooler in
summer and warmer in winter.
This has a great influence over the
climate of our area.