6.3: Global Climate Patterns
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The interaction of the atmosphere with the hydrosphere and the lithosphere create weather and climate. The study of weather and climate is an entire course unto itself. Therefore, in this section I will be going over the bare essentials of how latitude and location on a continent affects the weather and climate of a place.
You may recall our discussion of how Hadley cells create bands of low pressure (due to the rising air masses) at the equator, and bands of high pressure (due to the falling air masses) at the tropics (23.5º North or South). You may also recall that high pressure is associated with dry, sunny weather, and low pressure is associated with wet, cloudy weather. In Africa, large bands of desert are approximately 23.5º North, and to a lesser extent in North America. You might want to research the bands of equatorial rainforest across Africa and South America.
Climate is classified by both average annual precipitation and average annual temperature ranges. Note the graphs at the bottom of the world climate map.These are called climatograms. They are a type of graph that shows you annual temperature ranges and precipitation totals for an average year (would this be weather or climate?). The x-axis represents the months of the year. The left y-axis represents the temperature in degrees F. The right y-axis represents precipitation in inches (can you find the typo in the atlas?).
Modelland is an imaginary continent on our earth. All of the patterns of ocean circulation and predominate winds apply to it. You might think of Modelland as a picture of the earth past, or a future vision of the earth. The letters denote locations whose climate will be discussed below. Test yourself by matching the climate descriptions with the letters below.
- B & C are deserts because it is located in a zone of high pressure.
- A is a lush tropical forest because it is located in a zone of low pressure.
- F is located in a rainshadow.
- D are cool polar currents.
- E are warm tropical currents.
- J is an example of continenality.
- K is an example of oceanality.
- I is much more cool than H because it is at a higher altitude.
Below are examples of temperature profiles for H & I (effect of altitude on temperature) and J & K (oceanality/continality effects)