Heating and Cooling Systems

Heating and Cooling Systems

http://www.brainpop.com/science/weather/weather/

http://www.brainpop.com/science/weather/weather/

Objective: Students are responsible:Analyzing the effects

of heating and cooling processes in

weather.

• 1. Where does Earth receive its thermal energy?

• 45% comes from the sun itself

• 55% radiates from the earth to the atmosphere and then back to earth

• 2. Why is the temperature of the earth relatively constant?

• 3. What is the earth’s relative constant temperature.

• Earth re-emits the heat as infrared radiation. – Some of the emitted

heat is reabsorbed in our atmosphere and the rest goes into space.

• The earth remains a constant 27°C.

• 4. What is Global Warming

• when the atmosphere reabsorbs too much heat

Sun

Earth’s Temperature

Solar

Energy

Solar

Energy

Solar

Energy

Solar

Energy

Sun

Earth’s Temperature

Solar

Energy

Solar

Energy

RadiativeCooling

RadiativeCooling

Sun

Earth’s Temperature

Solar

Energy

Solar

Energy

RadiativeCooling

RadiativeCooling

5. What is the Greenhouse Effect

• the warming of Earth due to carbon dioxide and other gases

• Warming occurs as sunlight strikes the Earth. Much of the sunlight is reflected back into space.

• But Earth's atmosphere absorbs much of the heat and slows its escape from Earth. In this way, the Earth is like a greenhouse.

• The atmosphere encloses the Earth just as panes of glass enclose a greenhouse.

• Because of their heat-trapping abilities, the carbon dioxide and other gases in Earth's atmosphere are often called greenhouse gases.

Greenhouse EffectSun

Earth’s Atmospheric Gases

Nitrogen (N2)

Oxygen (O2)

Water (H2O)

Carbon Dioxide (CO2)

99%

Methane (CH4)

1%

Non-Greenhouse

Gases

GreenhouseGases

Ice Sheets Melting?

• GRACE (gravity measured by satellite) found melting of Antarctica equivalent to sea level rise of 0.4 mm/year (2 in/century)

• Zwally, 2005 (satellite radar altimetry) – confirmed Antarctica melting– Greenland ice melting on

exterior, accumulating inland(higher precipitation)

Rise in Sea Levels?

• Present rate is 1.8 ± 0.3 mm/yr (7.4 in/century)

• Accelerating at a rate of 0.013 ± 0.006 mm/yr2

• If acceleration continues, could result in 12 in/century sea level rise

• Scenarios claiming 1 meter or more rise are unrealistic

Increase in Hurricanes?

• Two studies showed the total number of hurricanes has not changed

• However, the intensity of hurricanes has increased (more category 4 and 5 hurricanes and cyclones)

• Probably due to higher sea surface temperatures (more energy)

• Difficult to know if this trend will continue

• Two studies showed the total number of hurricanes has not changed

• However, the intensity of hurricanes has increased (more category 4 and 5 hurricanes and cyclones)

• Probably due to higher sea surface temperatures (more energy)

• Difficult to know if this trend will continue

How Much Temperature Increase?

• Some models propose up to 9°C increase this century

• Two studies put the minimum at 1.5°C and maximum at 4.5°C or 6.2°C

• Another study puts the minimum at 2.5°C

Wildlife Effects

• Polar Bears– Require pack ice to live– Might eventually go extinct in the wild

• Sea turtles– Breed on the same islands as

their birth– Could go extinct on some islands

as beaches are flooded

• Other species may go extinct as rainfall patterns change throughout the world

• Polar Bears– Require pack ice to live– Might eventually go extinct in the wild

• Sea turtles– Breed on the same islands as

their birth– Could go extinct on some islands

as beaches are flooded

• Other species may go extinct as rainfall patterns change throughout the world

Effect on Humans

• Fewer deaths from cold, more from heat

• Decreased thermohaline circulation– Cooler temperatures in North Atlantic

• CO2 fertilization effect

• Precipitation changes• Droughts and famine (some areas)• Expanded arable land in Canada, Soviet Union

Mitigation of Global Warming

• Conservation– Reduce energy needs– Recycling

• Alternate energy sources– Nuclear– Wind– Geothermal– Hydroelectric– Solar– Fusion?

• 6. What causes wind?

• 7. Why does earth have seasons?

• 8.What is humidity?

• 9. Relative Humidity index

• uneven heating of the

Earth.

• The tilt of the axis of earth.

• How much water vapor the air has

• 10. What is the dew point?

• 11. How does rain form?

• 12. Where does fog come from?

Temperature when air and water vapor are 100 %

• Water often condenses onto particles of dust in the atmosphere.

• When air near the ground is cooled below the dew point.

• 13. Warm Front

• 14. Cold Front

• 16. What happens when cold front and warm front meet?

• Warm air overtakes the cold air.

• A mass of cold air lifts and pushes warm air aside.

Both can produce dramatic weather.

THE END!!!