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