Science 10 Chapter 10.3_keyed
Chapter 10 - Solar Energy and Climates (pages 362 - 399
in your text)
Chapter 10.3 – Distributing the Heat (pages 388 – 396 in your text)
Every year, Calgary hosts a winter carnival where you can see really “cool” ice sculptures.
During Calgary’s winter, ice sculptures are usually able to remain frozen. Meanwhile, only
approximately 1000 km away, Vancouver’s winters are mild—too mild to maintain ice
sculptures over weeks at a time.
Vancouver’s winters are mild, especially compared to the prairie cities, due to thermal energy
carried by a warm ocean currents flowing past the west coast. Ocean currents carry much of the
thermal energy transferred by the hydrosphere. These transfers of thermal energy have a
profound effect on climate around the globe.
How Oceans Distribute Heat
Water has a low albedo and absorbs more than 90% of the solar energy striking it. Because of
water’s high specific heat capacity and large heats of vaporization and fusion, it takes a lot of
energy to change its temperature or phase. The energy absorbed by water is distributed
throughout great water depths due to waves, turbulence and ocean currents.
The Gulf Stream is a large surface
current that starts in the Caribbean
and follows the coastline of the
United States and Canada. It ends
up off the European coast, where
it is called the North Atlantic
Drift. This current helps to
moderate the climates of Western
Europe.
El Niño and La Niña
El Niño is a disruption of the
ocean-atmosphere system in the
tropical Pacific that typically
occurs every three to seven years. During an El Niño year, the wind direction over the South
Pacific reverses and the winds flow eastward. The wind reversal causes an increase in the seasurface temperature, causing heavy rains in South America and droughts in Asia and Australia. It
is not known why the winds reverse directions. El Niño can affect weather patterns across 25%
of the globe.
La Niña is the opposite of El Niño. La Niña is characterized by an increase in the strength of the
normal patterns of westward moving winds. La Niña produces wetter than normal conditions in
Australia and Asia. North America becomes warmer and drier than in non- La Niña years.
Here is a rule that is not always exactly true, but still is useful to compare the impacts of El Niño and his contrary
sister. Where El Niño is warm, La Niña is cool. Where El Niño is wet, La Niña is dry. While El Niño conditions and
their seasonal impacts look very different from normal, La Niña conditions often bring winters that are typical — only
Science 10 Chapter 10.3_keyed
more so. There's something else to keep in mind: El Niño and La Niña tend to make seasonal conditions one way or
another, but every El Niño and La Niña is different.
What to do: Answer the questions below.
Question 1. In the northern hemisphere, ocean currents that flow north tend to be warm currents
and those that flow south tend to be cold currents. Give a reason for this.
In the northern hemisphere, ocean currents that flow north tend to be warm currents because they
are coming from the warmer regions close to the equator. Ocean currents that flow south tend to
be cold currents because they are coming from the cooler, polar regions.
Question 2. In which hemisphere do ocean currents flow clockwise? In which hemisphere do
they flow counterclockwise?
Ocean currents flow clockwise in the northern hemisphere and counterclockwise in the southern
hemisphere.
Question 3. Name the regularly occurring disruption of ocean currents in the tropical Pacific that
is linked to severe weather and climate events around the globe.
This disruption of the ocean currents is called El Niño.
Patterns of Wind Movement
Living in Alberta, you probably notice that wind most often comes from the west. That is
because Alberta is in the temperate zone where west-to-east winds blow. These winds, called
prevailing westerlies, contribute to global wind patterns.
animation of global wind patterns
At the equator, warm air rises and loses its
moisture. At 30◦, dry air descends; therefore,
deserts occur at 30◦ latitude around the
world.
Because the Earth is rotating on its axis, the
trade winds move from the northwest to the
west in the Northern hemisphere, and from
southeast to the west in the Southern
hemisphere. This is called the Coriolis
effect.
The westerlies move from the west, towards
the east.
Differences in atmospheric pressure in neighbouring regions on Earth’s surface lead to wind.
An area of low pressure occurs as warm air expands, becomes less dense, and rises from the
surface. High pressure occurs as cold air contracts, becomes denser, and descends to the surface.
This movement of air forms convection currents that circulate and distribute heat around the
world.
Science 10 Chapter 10.3_keyed
The Earth is constantly rotating and the atmosphere rotates with it at the same speed. Convection
currents or any moving object tend to veer sideways from their original course due to Earth’s
rotating eastward on its axis. This tendency is called the Coriolis effect.
Jet Streams
Jet streams are currents of extremely fast-moving air about 10-15 km
above Earth’s surface. Jet streams form at the boundaries of cold and
warm air. Jet streams are usually larger in the winter when the
temperature difference between cold and warm air masses is greatest.
Intense winds within jet streams influence precipitation and
thunderstorms.
What to do: Answer the questions below.
Question 4. In which direction does air move with regards to pressure areas?
Air moves from a high-pressure area to a low-pressure area.
Question 5. Why does an area of high pressure form where the air is cold?
When air cools, it contracts and becomes more dense. A column of more dense air exerts more
pressure and, thus, forms an area of high pressure.
Question 6. Earth’s rotation deflects airflow from a direct north-south direction. What is
this deflection called? The deflection of airflow due to Earth’s rotation is called the Coriolis
effect.
Oceans and Mountains Influence Climate
Sea and land breezes form as a result of the vastly different specific heat capacities of water and
land. Water heats and cools at a slower rate than land. This results in a temperature differential
between the two bodies.
Sea Breeze (occurs during the day)
A – Sun’s rays warm the land faster than they warm the
water
B – Warm air is less dense; warm air rises.
C – Air over the water is cooler; cool air is more dense and
sinks.
D – Cool air flows towards land to replace the warm air
that has risen
Land Breeze (occurs at night)
A – The sea loses heat more slowly than the land. The air
over the sea is warmer.
B – Warm air over the sea rises.
C – Air over land is cooler; cool air is more dense and
sinks.
D – Cool air flows towards the sea to replace the warm air
that has risen.
Science 10 Chapter 10.3_keyed
What to Do: Answer each question in the space provided.
1. Explain why different surfaces absorb different amounts of solar energy.
The phenomenon is called albedo. Dark surfaces absorb solar energy, while light surfaces reflect
solar energy.
2. Match the description in column A with the correct term in column B. Write the term in the
line beside the description.
A
B
(a) relatively fast uniform winds that are found in the upper atmosphere in a albedo
narrow band jet stream
convection
(b) phenomenon that causes moving air masses to be deflected to the right
in the Northern Hemisphere and to the left in the Southern Hemisphere
Coriolis effect
Coriolis Effect
(c) movement of a gas or a liquid because of heating convection
El Niño
(d) name given to the occasional development of warm ocean surface
Gulf Stream
waters along the coast of Ecuador and Peru El Nino
(e) condition that develops when warm air rises and becomes less dense
high pressure
low pressure
(f) condition that develops when cold air contracts and becomes more
jet stream
dense high pressure
(g) warm Atlantic current that splits into two as it reaches the British Isles
land breeze
North Atlantic Drift
low pressure
(i) breezes that occur during the day due to differential heating between
land and water sea breeze
North Atlantic Drift
(j) breezes that occur during the night due to differential cooling between
land and water land breeze
sea breeze
(k) measure of the how much radiation a substance or an object reflects
albedo
(l) warm ocean current that originates in and around the Caribbean and
flows across the North Atlantic to northwest Europe Gulf Stream
3. Sketch a diagram of either a sea breeze or a land breeze. Include the
following labels with your diagram:
- “sea breeze” or “land breeze”
- “daytime” or “nighttime”
- “hot”
- “cool”
- “warmer air rising”
- “cooler air sinking”
- arrows showing direction of breeze.