1. Basic Geoscience
Unit 5 Lecture

2. Radiant Energy
Radiant energy comes from the sun and travels through space to heat the earth
This heating of the earth is called radiation

3. Absorption of Energy
Dark surfaces absorb more light, which converts into heat
Light colored surfaces reflect light and remain cooler than darker surfaces

4. Energy From the Sun
50% of the sun’s energy is absorbed by the surface of earth
20% is absorbed by the earth’s atmosphere
30% is reflected by the earth’s atmosphere and surface total

5. Energy From the Sun

6. There are 3 ways for heat to move:
1. conduction
2. convection
3. radiation
Heat always moves from hot objects to cooler objects

7. Conduction Near the earth’s surface, heat moves through matter
By contact with solids
This is conduction
Ex: hot air touching the warm dirt

8. Radiation Radiation are waves of energy that travel through a vacuum
Outer space is a vacuum
Shortwave radiation (powerful) comes from the sun
Long wave radiation is released by the earth back into the atmosphere

9. Convection
Convection is heat being transferred through gases or liquids
Convection currents are formed because warm air expands and rises, cool air contracts and sinks

10. Winds and Air Pressure
Air movement is determined by differences in air pressure
Horizontal air movement is called wind
This is the most common.
Vertical air movement are called updrafts and downdrafts.

11. Highs= cold, heavy air
Lows= warm, light air
Air moves from high pressure to low pressure.
The greater the difference in pressure, the faster the wind moves.

12. Air Currents
Hot air expands and rises
Cool air contracts and sinks

13. The Big Idea Trade winds- reliable winds above and below the equator
Doldrums- area between the trade winds where there is little wind
Prevailing Westerlies- winds between the polar area and the trade winds (also called anti trade winds because they move in the opposite direction)

14. Horse latitudes- located between the westerlies and the trade winds
Little wind occurs here
Polar Easterlies- cold and dense, slow winds

16. Sea and Land Breezes
A breeze coming from the sea towards land is a sea breeze.
This happens during the day.
A breeze coming from the land towards the sea is a land breeze.
This happens during the night.

18. Mountain and Valley Breezes
A valley breeze happens when air moves from the valley up a mountain.
This happens during the day.
A mountain breeze happens when air moves down from the mountain into the valley.
This happens at night.

20. Monsoons Monsoons are winds that change direction with seasons.
During summer, the wind moves from the ocean towards the land and causes many rains.
During winter, the wind moves from the land towards the ocean and is associated with dry air.

21. Air Masses
An air mass is a large body of air with certain characteristics of temperature and moisture throughout.
Masses over land are dry.
Masses over water are moist.

22. Polar Air Masses
Polar air masses are cold air masses that form over polar regions.
cP- cold and dry
Ex: Canada
mP- cold and moist
Ex: north east and west coast of North America

24. Tropical Air Masses cT- warm and dry Ex: Mexico mT- warm and moist
Ex: Caribbean

25. Boundaries In Air Fronts are boundaries where two air masses meet
This brings changes in the weather

26. Cold Fronts
This occurs when cold air pushes under warm because the cold air is more dense
Causes rainy and cloudy skies

27. Warm Fronts Occurs when warm air pushes over cold air
This front moves slowly
You will see cirrus clouds and precipitation

28. Stationary Fronts This occurs when air masses meet and do not move
There is little change in the weather when this happens.

29. Occluded Fronts
This occurs when warm air is stuck between two cooler air masses.
The cool air pushes the warm air up
The weather during this time is cloudy, rainy, and snowing