Geography Reference
In-Depth Information
The differences among the Bundles in Figure 9-1 are determined by the curvature of the
Earth. Bundle A contains
vertical rays,
which strike Earth perpendicularly. Due to curvature,
however, Bundle B strikes Earth at a sharper angle. As a result, its solar energy is spread over
a larger area than is Bundle A's. Sharper still, thanks to curvature, is the angle at which Bundle
C strikes Earth. And as a result, its heat is spread over the largest area of the three examples.
Absent other factors that affect temperature, Area A has the warmest climate because it has the
greatest concentration of solar energy. That is, the heat in Bundle A is brought to bear on a relatively
small area. In contrast, Area C has the coldest climate because the heat it receives is spread over the
largest of the three areas. Intermediate conditions are present in Area B.
Let's look at some real locales and compare the climates of Manaus, Brazil, and Churchill, Manitoba
(Canada). Manaus is located at about Latitude 3° South and therefore exemplifies Area A on the dia-
gram. Churchill is located at Latitude 58° North and therefore has the characteristics of Area C.
In Manaus, the annual average temperature is 79° F. (That means that if you recorded the temperature
every hour of every day for a year, the average would be 79° F). In Churchill, it's 19° F. The differ-
ence is 60° F. Manaus is much warmer.
Beware the reason! Is it because Manaus is closer to the equator? Nope. Proximity to the
equator
per se
is not the explanation. Instead, the answer lies in the angle. The sun is more
directly overhead at Manaus than at Churchill throughout the year. Thus, Manaus experiences
a greater concentration of solar energy throughout the year and is therefore a warmer climate.
Making rain and snow
Climate is about precipitation as well as temperature. Regarding wet stuff, Manaus receives 82 inches
of precipitation on average each year. Churchill, in contrast, receives 15 inches. Thus, the precipita-
tion difference in inches is even greater than the temperature difference in degrees Fahrenheit. Again,
sun angle plays a major role in these particular cases.
