Transcript Thermal Energy and Heat

Aspect of Weather
Earth’s Energy Budget
 Just like a family makes a money budget for their
home, Earth makes a solar energy budget for it’s
overall temperature.
 An energy budget is vital to the sustainability of earth,
as temperatures that are too low or too high can have a
devastating impact on Earth’s Biosphere (area that
houses all living things).
How it works:
 Earth’s atmosphere and crust absorb heat to maintain
earth’s temperature (incoming radiation) and emit
heat back into the atmosphere (outgoing radiation)
 Pg. 14 ~ Figure 1.4
 Important Budget Values:
 49% of the incoming solar radiation is absorbed by land
and ocean.
 42% of incoming solar radiation is absorbed, reflected,
and scattered by clouds, gases, and aerosols in the
atmosphere.
 9% is reflected by Earth’s surface.
Factors Affecting Absorption of Energy
 COLOUR
 Dark surfaces absorb light
 Light surfaces reflect light
 ALBEDO: reflectivity of a surface or how much energy it
reflects.
 Snow has a high albedo
 Field crops have a low albedo.
 TYPE OF SURFACE: different surfaces absorb energy at
different rates.
 water heats up and cools much slower than land while
 air heats up and cools much faster than land and water.
Specific Heat Capacity
 The property of a substance that involves how (and
how quickly) it absorbs and/or releases energy.
 Water has a much higher specific heat capacity than
land and air, meaning it can absorb a lot of energy and
release it slowly.
Heat Sinks
 Any substance that can absorb and retain a “pool” or
reservoir of energy without undergoing a change of
state.
 Water is a better heat sink than land.
 As a result, our oceans have a great influence on
weather.
 Example: coastal areas have cooler summers and mild
winters.
Summary of some key concepts
Please copy down the following
summary organizers on the next
three slides…
Incoming Radiation
vs.
Emitted by the Sun as
Shortwave radiation
Absorbed by land, water, atmosphere,
And some gets reflected back to space.
High concentration
of thermal energy (heat)
Outgoing Radiation
Emitted by land, water
as Longwave radiation
Absorbed by atmosphere
and moves up to exit
the atmosphere.
Low concentration
of thermal energy (heat)
Dark and Dull Surfaces
Great absorbers of energy, heat
up quickly. (low albedo)
vs.
Light and Shiny Surfaces
Do not absorb energy well,
reflect a lot of energy, heat
up slowly. (high albedo)
Example:
Example:
Downtown of cities are
hotter because of their
dark surfaces (lots
pavement, buildings).
In the winter, more energy
is reflected away from our
surfaces because of snow.
LAND
Low heat capacity
(does not need to absorb
a lot of thermal
Energy to rise in temp.)
vs.
WATER
High Heat Capacity.
(needs to absorb a lot of
thermal energy to rise in
temperature. )
GOOD HEAT SINK!!!!
As a result of this…
As a result of this….
Land heats up quickly
and cools quickly!
Water heats up slowly
and cools slowly.
Example: In the summer, at a beach,
sand (land) is hotter than water!
Coasts lower temp than inland areas
Example: In the winter, the water
is warmer than the land. Coasts
higher temp than inland areas.
Your Task:
 Complete the handout “Heat Sinks & Heat Capacity”
 Refer to your PPT note and summary diagrams you just
copied down.