Page 340 - Geosystems An Introduction to Physical Geography 4th Canadian Edition

304 part II The Water, Weather, and Climate Systems
concepts review
key learNING
■ Define climate and climatology, and review the princi- pal components of Earth’s climate system.
Climate is a synthesis of weather phenomena at many scales, from planetary to local, in contrast to weather, which is the condition of the atmosphere at any given time and place. Earth experiences a wide variety of cli- matic conditions that can be grouped by general simi- larities into climatic regions. Climatology is the study of climate and attempts to discern similar weather statistics and identify climatic regions. The principal factors that influence climates on Earth include insolation, energy imbalances between the equator and the poles, tempera- ture, air pressure, air masses, and atmospheric moisture (including humidity and the supply of moisture from precipitation).
climate (p. 276) climatology (p. 276) climatic region (p. 276)
1. Define climate and compare it with weather. What is climatology?
■ Describe climate classification systems, list the main categories of world climates, and locate the regions characterised by each climate type on a world map.
Classification is the ordering or grouping of data or phe- nomena into categories. A genetic classification is one based on causative factors, such as the interaction of air masses. An empirical classification is one based on statis- tical data, such as temperature or precipitation. This text analyzes climate using aspects of both approaches. Tem- perature and precipitation data are measurable aspects of climate and are plotted on climographs to display the basic characteristics that determine climate regions.
World climates are grouped into six basic categories. Temperature and precipitation considerations form the basis of five climate categories and their regional types:
• Tropical (tropical latitudes)
• Mesothermal (midlatitudes, mild winters)
• Microthermal (mid and high latitudes, cold winters)
• Polar (high latitudes and polar regions)
• Highland (high elevations at all latitudes)
Only one climate category is based on moisture efficiency as well as temperature:
• Dry (permanent moisture deficits)
classification (p. 276)
genetic classification (p. 277) empirical classification (p. 277) climograph (p. 277)
2. What are the differences between a genetic and an empirical classification system?
3. What are some of the climatological elements used in classifying climates? Why is each of these used? Use the approach on the climate classification map in Figure 10.2 in preparing your answer.
4. List and discuss each of the principal climate categories. In which one of these general types do you live? Which category is the only type associ- ated with the annual distribution and amount of precipitation?
5. What is a climograph, and how is it used to display climatic information?
6. Which of the major climate types occupies the most land and ocean area on Earth?
7. How do radiation receipts, temperature, air pressure inputs, and precipitation patterns interact to produce climate types? Give an example from a humid envi- ronment and one from an arid environment.
■ Discuss the subcategories of the six world climate groups, including their causal factors.
Tropical climates include tropical rain forest (rainy all year), tropical monsoon (6 to 12 months rainy), and tropi- cal savanna (less than 6 months rainy). The shifting ITCZ is a major causal factor for seasonal moisture in these climates. Mesothermal climates include humid subtropi- cal (hot to warm summers), marine west coast (warm to cool summers), and Mediterranean (dry summers). These warm, temperate climates are humid, except where high pressure produces dry-summer conditions. Microthermal climates have cold winters, the severity of which depends on latitude; subcategories include humid continental (hot or mild summers) and subarctic (cool summers to very cold winters). Polar climates have no true summer and in- clude tundra (high latitude or high elevation), ice-cap and ice-sheet (perpetually frozen), and polar marine (moder- ate polar) climates.
8. Characterise the tropical climates in terms of tem- perature, moisture, and location.
9. Using Africa’s tropical climates as an example, char- acterise the climates produced by the seasonal shift- ing of the ITCZ with the high Sun.
10. Mesothermal climates occupy the second largest portion of Earth’s entire surface. Describe their tem- perature, moisture, and precipitation characteristics.
11. Explain the distribution of the humid subtropical hot-summer and Mediterranean dry-summer cli- mates at similar latitudes and the difference in pre- cipitation patterns between the two types. Describe the difference in vegetation associated with these two climate types.
12. Which climates are characteristic of the Asian mon- soon region?
13. Explainhowamarinewestcoastclimatecanoccurin the Appalachian region of the eastern United States.
14. What role do offshore ocean currents play in the distribution of the marine west coast climates? What type of fog is formed in these regions?
15. Discuss the climatic conditions for the coldest places on Earth outside the poles.
■ Explain the precipitation and moisture-efficiency crite- ria used to classify the arid and semiarid climates.
The dry climates of the tropics and midlatitudes consist of arid deserts and semiarid steppes. In arid deserts, pre- cipitation (the natural water supply) is less than one-half of natural water demand. In semiarid steppes, precipita- tion, though insufficient, is more than one-half of natural