World Geography 3202
Unit 2: Patterns in Weather &
Climate
Temperature Patterns
2.2.1 Greenhouse Effect
• The greenhouse effect is often misunderstood and
mistaken for "Global Warming". This effect is important
because it moderates the earth’s temperature.
• Planets without atmospheres have an extreme range in
temperature between day and night. On earth the
atmosphere reflects and absorbs almost 50% of radiant
energy.
• Planets where there is no atmosphere get very cold at night
due to the absence of sunlight. No atmosphere results in
loss of heat. On the earth, the atmosphere acts like the
glass on a greenhouse keeping some heat.
Greenhouse Effect!
2.2.2. The Tropics and The Poles
• The tropics refers to warm equatorial climates.
They are located between 23.5 degrees north and
23.5 degrees south.
• The more direct the sunlight the more intense
the heat. The tropics receive direct sunlight.
Areas outside the tropics receive more indirect
sunlight.
• The further you move outside the tropics,
temperatures tend to decrease, and seasons
become more severe.
The Tropics
Lines of Latitude
• Key Idea!: As lines of latitude increase,
temperatures tends to decrease!
2.2.2 -3
Latitude and Temperature (cont’d)
Why The Poles Are Colder Than The Tropics?
• The poles of the earth are colder than the
equatorial regions of the earth because of the
earth's spherical shape.
• When light hits the equator, the sunlight is direct
and has to heat a small area. Conversely, when
light hits the polar regions it is less direct and has
to heat a larger area, due to the curvature of the
earth. This energy from the sun is not as warm.
• The ultimate result is more intense heating in the
tropics due to more direct sun.
• It is not related to the earth’s tilt, revolution or
rotation. They explain the seasons!
2.2.2-4
Latitude and Temperature
• As latitude increases temperature decreases.
Latitude and temperature are inversely
proportional.
• Figure 4.7 on page 60 of your text book shows a
map that indicates the change in temperature
with latitude. You can see from that map that the
general trend does hold true, increased latitude
exhibits decreased temperature.
• Other factors also come into play, these include;
ocean currents, prevailing winds, and altitude.
Checking for Understanding!
• Do Worksheet 4.1 and 4.2
• Read pp. 54-60
• Using the slides/notes and the textbook
reading, answer these questions:
• Page 56, # 10 a & b
• Page 57, #’s 11 & 12
• Page 58, #’s 13 a & b