Geoscience Reference
In-Depth Information
At its most general level, the system recognizes six major cli-
mate groups ( A , B , C , D , E , H ). Climate groups A , B , C , D ,
and E range from tropical latitudes near the Equator ( A ) to high
latitudes at the poles ( E ) and cover huge geographical areas.
Climate group H is the designation for high-altitude regions,
regardless of latitude, and may be found in isolated places. Each
of these major climate groups is distinguished on the basis of
temperature, except for category B , which is based on moisture
characteristics. The Köppen A climate zones, for example, have
a mean temperature each month > 18°C (64°F), whereas the D
climate regions have average temperature > 10°C (50°F) in four
months to eight months. B climate regions are recognized as
those with mean annual precipitation < 76 cm (30 in.).
Although it is often sufficient to note the fundamental cli-
mate characteristics over broad areas, geographers are usually
interested in the more specific attributes of smaller regions.
To accomplish this task, the major Köppen groups are further
subdivided on the basis of temperature and moisture by use of a
second letter, and sometimes even a third. Climate regions with
a second letter s , for example, have a distinct summer dry sea-
son. In contrast, areas with a second letter w have an observable
winter dry season. Those areas further classified with a third
letter a have a warmest month that has an average temperature
> 22°C (71.6°F). Table 9.1 outlines the various Köppen letter
designations and their meanings as far as specific environmen-
tal characteristics are concerned. The full range of Köppen
climate types and subtypes is presented in Table 9.2, with the
geographic distribution of these classes shown in Figure 9.2.
As you might imagine, the Köppen classification system
can be very cumbersome to use because it contains a lot of jar-
gon. At this introductory level, your goal should be to under-
stand the fundamental characteristics of the 23 major climate
regions and avoid becoming overwhelmed by all the specific
reasons why the many subcategories occur. With this strategy
Arctic Circle
Tropic of Cancer
Equator
Equator
Tropic of Capricorn
Antarctic Circle
Tropical Humid Climates
Arid/Semi-Arid Climates
Mesothermal Climates
Af
Am
Aw
Tropical Rain Forest
Tropical Monsoon
Tropical Savanna
BWh
BWk
BSh
BSk
Hot Low-Latitude Desert
Cold Midlatitude Desert
Hot Low-Latitude Steppe
Cold Midlatitude Steppe
Cfa
Cfb
Csa
Cwa
Cfc
Csb
Humid Subtropical Hot-Summer
Marine West-Coast
Mediterranean Dry-Summer
Microthermal Climates
Polar Climates
Highland Climates
Dfa
Dfb
Dfc
Dwa
Dwb
Dwc
Humid Continental Hot-Summer
Humid Continental Mild-Summer
Subarctic
ET
EF
Tundra
Ice Cap
H
Highland
Dwd
Figure 9.2 Map of Köppen climates on Earth.
The Köppen system contains six major climate groups that are divided into as many as
23 subcategories.
 
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