Geoscience Reference
In-Depth Information
Maritime vs. Continental Effect
To see how the martime vs. continental effect occurs, view the
animation
Maritime vs. Continental Effect
. In this animation,
you can observe how temperature varies over the course of
the day at Yuma, Arizona, and San Diego, California. Although
San Diego and Yuma are both located at about the same lati-
tude (~33° N), and thus receive about the same amount of daily
insolation, the range in daily temperature differs dramatically
between the two places. Watch how air temperature varies be-
tween these two places over the course of the day and year and
relate what you see to the previous discussion in this text. After
you complete the animation, be sure to answer the questions at
the end to test your understanding of this concept.
VISUAL CONCEPT CHECK
5.2
One of the most beautiful cities in North America is
Vancouver, British Columbia. This Canadian city is particu-
larly scenic because it lies between the Haro Strait, which
is connected to the Pacific Ocean to the west, and the
Cascade Mountains to the east. Although Vancouver lies
at a fairly high latitude (49° N), it has a very moderate cli-
mate with average high temperatures that range from 22°C
(71°F) in July to 6°C (43°F) in December. Which one of the
following reasons accounts for this temperature pattern?
a)
Vancouver is a continental location.
b)
Vancouver lies next to a large body of water that
has a consistent annual temperature.
c)
The wind in Vancouver generally flows from east to
west.
d)
The Pacific Ocean has a wide range of annual
temperature.
and increased insolation. The maritime vs. continental effect is
evident in the range of latitude that the isotherm shifts in each
hemisphere. Notice that, in the oceans, the isotherm does not
move much compared to how it migrates on the landmass. This
difference is due to the fact that large water bodies heat and cool
much more slowly than do continents.
Given the seasonal and geographic pattern observed in
Figure 5.10, consider the broad-scale range cycle of tempera-
ture on Earth. Once again, a good place to begin is by examin-
ing some illustrations that show the fundamental patterns. With
this in mind, take a look at Figure 5.11, which shows mean air
temperatures on Earth during January and July.
Beginning with the January image, observe that the land-
masses in the Northern Hemisphere are quite cold, with tempera-
tures in northeastern Asia (Siberia) of
Ľ
50°C (
Ľ
58°F) and
Ľ
35°C
(
Ľ
31°F) in northern Canada. An interesting pattern exists in North
The Annual Range of Surface
Temperature (A Holistic Assessment)
Let's now bring together some of the variables that influence
temperature around the world in an effort to see some funda-
mental global geographic patterns. A good place to begin is by
considering Figure 5.10, which shows a hypothetical continent
bordered on the east and west by oceans. This theoretical con-
tinent straddles the Equator and contains, as a point of refer-
ence, the hypothetical position of the 15°C (59°F) isotherm in
January and July. This diagram shows the combined effects of
the maritime vs. continental relationship and seasonality. Due
to seasonality, the isotherm shifts into the Southern Hemisphere
during that hemisphere's summer season (January) and back into
the Northern Hemisphere during July. This migration occurs
because a net surplus of radiation occurs in each hemisphere
