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Geography 101 Lab 8
Climate Classification and Regional Climates – Practice Questions
You should be able to explain how ocean currents affect air stability and precipitation.
1.
Calculate the average total precipitation, the average annual temperature, and the average maximum range in temperature
for the six west coast cities and the six east coast cities listed in Table 1.
2.
How does the average total precipitation for the west coast cities compare to that for the east coast cities? Why is this the
case?
Total precipitation is much lower on the west coast than on the east coast (275.4 mm compared to 1368.1 mm).
The cold ocean current along the west coast cools the air above it, which inhibits the air from rising; cool air is too
dense to rise, so clouds don’t form and precipitation is low.
The warm ocean current along the east coast warms the air above it, which encourages the air to rise and promotes
cloud growth and high precipitation.
3.
How does the average annual temperature for the west coast cities compare to that for the east coast cities? Why is this
the case?
The average annual temperature is lower on the west coast than on the east coast (17.2°C compared to 20.0°C).
The cold ocean current along the west coast results in cooler temperatures while the warm ocean current along the
east coast results in warmer temperatures.
4. How does the average maximum range in temperature for the west coast cities compare to that for the east coast cities?
Why is this the case?
The average maximum range in temperature (highest maximum temperature minus the lowest minimum
temperature) is smaller on the west coast than on the east coast (19.4°C compared to 25.8°C).
Weather on the west coast comes from the ocean which doesn’t get very hot in the summer or very cold in the
winter resulting in small temperature ranges for the west coast cities.
Weather on the east coast comes from the middle of the continent, which gets quite hot in summer and quite cold in
winter, giving the east coast cities a larger temperature range.
TABLE 1. Climate Data for east and west coast cities in North America at similar latitudes.
Latitude
(°N)
Total Ppt
(mm)
Avg Annual
Temp (°C)
Max Ann T
Range (°C)
East Coast City
Latitude
(°N)
Total Ppt
(mm)
Avg Annual
Temp (°C)
Max Ann T
Range(°C)
Monterey
36.6
454.6
13.0
14.2
Virginia Beach
36.5
1127.6
15.5
31.0
Santa Barbara
34.4
360.0
14.3
16.3
Jacksonville, NC
34.4
1290.0
17.0
30.0
San Diego
32.7
264.0
17.6
15.6
Charleston
32.9
1298.0
18.8
29.7
Ensenada
31.9
226.0
17.2
19.4
Jacksonville, FL
30.5
1333.4
19.5
28.1
El Datil
26.9
236.0
21.3
29.1
W. Palm Beach
26.7
1587.4
24.1
18.5
A. L. Mateos
25.2
112.0
19.6
21.6
Miami
25.8
1572.2
25.1
17.3
Averages
31.3
275.4
17.2
19.4
Averages
31.1
1368.1
20.0
25.8
West Coast City
You should be able to explain how mountains affect spatial patterns of precipitation and climate type.
Figures 1 and 2 show precipitation and temperature data from cities in North America (blue dots and blue trend line) and
Europe (purple dots and purple trend line). The cities are at approximately the same latitude (48–49°N) in order to eliminate
the potential impact of latitude on temperature or precipitation. The x-axis represents the distance from the west coast.
5.
Describe how the temperature range changes (or not) starting at the west coast of North America and traveling eastward.
The temperature range on the west coast is approximately 15°C. As you travel east, the temperature range steadily
increases to approximately 50°C.
6.
Describe how temperature range changes (or not) starting at the west coast of Europe and traveling eastward.
The temperature range on the west coast is approximately 16°C. As you travel east, the temperature range slowly
increases to approximately 32°C.
7.
Based on the four European cities and the four North American cities closest to the coast, what is the approximate
temperature range for west coast cities on both continents? Why are these temperature ranges similar?
The average temperature range is about 20°C.
The similarity in temperature range results in part from the cities being at approximately the same latitude and in
part from the moderating influence of cool ocean currents adjacent to the coast. Neither the Atlantic nor the Pacific
Ocean warms much in the summer or cools much in the winter causing the coastal cities to have similarly small
temperature ranges.
8.
What is the approximate temperature range for the four North American cities farthest from the coast and for the four
European cities farthest from the coast? Why is the temperature range for the North American cities larger than for the
European cities?
North American temperature range is approximately 47 or 48°C.
European temperature range is approximately 29°C.
In Europe, the moderating impact of cool ocean currents continues to affect the temperature range for cities 15 – 20
degrees away from the coast. Air masses in these cities will all be relatively humid. The water vapor in the air will
help absorb outgoing longwave radiation, preventing it from escaping out to space. This will keep temperatures
more constant. The presence of lots of water vapor also means that some available energy gets used for latent heat
flux, not sensible heat flux.
In North America, mountain ranges block moist air from traveling inland. As air masses sink on the leeward side of
the mountains, temperatures warm and relative humidity decreases. The air masses in these cities will be relatively
dry (compared to the air masses in Europe). The lack of moisture in the air means that more of earth’s outgoing
longwave radiation will escape out to space, which results in larger changes in temperature. In addition, the low
humidity means more energy is available for sensible heat flux.
9.
Describe how precipitation changes (or not) starting at the west coast of North America and traveling eastward.
Precipitation is very high on the west coast and decreases dramatically as you travel east. About 12 degrees east of
the coast precipitation levels off at approximately 400 mm. Coastal precipitation is about six to seven times greater
than inland precipitation.
10. Describe how precipitation changes (or not) starting at the west coast of Europe and traveling eastward.
Precipitation on the west coast is only slightly higher (about two times greater) than precipitation farther inland.
11. What are the primary uplift mechanisms (orographic, convectional, cyclonic, frontal) causing precipitation on both
continents?
At latitudes of approximately 48–49°N, both North America and Europe get most of their precipitation from
midlatitude cyclones and fronts (cyclonic and frontal uplift).
12. Why is precipitation so much higher on the west coast of North America than on the west coast of Europe?
West coast locations in North America get additional precipitation from orographic uplift, so three uplift mechanisms
are at work: orographic, cyclonic, and frontal.
13. Precipitation fifteen degrees of longitude east of the west coast is lower in North America than in Europe. Why?
As air sinks down the leeward side of the mountains in North America, the air warms and relative humidity decreases,
which inhibits the formation of clouds and precipitation.
14. Based on the precipitation patterns, how far east from the coast do you think the marine west coast climate (Cfb) extends
in North America and in Europe?
In Europe, the marine west coast (Cfb) climate extends at least 30 degrees of longitude inland.
In North America, the marine west coast (Cfb) climate extends only about 5–7 degrees inland.
FIGURE 1.
FIGURE 2.
3000
Europe
North America
2500
50
Cascade Range
& Coast Mtns
40
Total Annual Precipitation (mm)
Maximum Annual Temperature Range (°C)
60
Rocky Mtns
30
20
10
Europe
10
20
Degrees of Longitude from the West Coast
Cascade Range
& Coast Mtns
1500
1000
500
North America
0
0
2000
30
0
0
Rocky Mtns
10
20
Degrees of Longitude from the West Coast
30