Geography Reference
In-Depth Information
In humid tropical climates, the average temperature of each month is 64° F or higher. The
warmth is a function of vertical rays (see Chapter 9) and near-vertical rays that strike the trop-
ical latitudes pretty much throughout the year. All that sunshine, in turn, generates high evapo-
transpiration (for more on this, see Chapter 8), producing a moisture-laden atmosphere, and
also creates convection currents (see Chapter 9 for more details) that cause the air to rise,
cool, condense, and cause rain. In consequence, annual precipitation is abundant and may oc-
cur year-round or in distinctive wet seasons that vary in intensity and duration. This variation
in precipitation distinguishes the three principal climates in the Humid Tropical category (see
Figure 10-2): tropical rainforest, tropical monsoon, and savanna — the latter is also known as
tropical wet and dry.
Figure 10-2:
The
geography of hu-
mid tropical cli-
mates.
As “tropical” suggests, these climates generally occur between Latitudes 23 1/2° North and
South. Figure 10-2 shows, however, a few decidedly non-equatorial areas where a tropical hu-
mid climate prevails due to warm water currents, orographic rainfall (see Chapter 9 for more
details), or some other mechanism. Conversely, “non-tropical” climates are occasionally seen
between The Tropics of Cancer and Capricorn thanks to the cooling effects of elevation, cold-
ocean-surface currents, or predominant wind directions.
Tropical rainforest
In areas of Tropical Rainforest climate all months average above 64° F and the driest month of
the year averages above 2.4 inches (6 cm) of rain. For all intents and purposes, therefore, this
climate may be described as warm and wet year-round. Although the equatorial low-pressure
