Page 160 - Geosystems An Introduction to Physical Geography 4th Canadian Edition

124 part I The energy–atmosphere System
JFMAMJJASOND maximum 34°
Average temperature
Concepción
Mean temperature
28°
Average
minimum 22° temperature
Temperature in (°C)
16°
10°
4°
Freezing Point 0° –2°
La Paz JFMAMJJASOND
80° 60° 50° 40°
10°
40°
0° 10°
20° 30°
0°
Concepción La Paz
0 1000 KILOMETRES
(a)
(b) Tropical dry forests cover the lower elevations of east-central Bolivia near Concepción; some forests have been cleared for farmland and ranching.
Station
20°
30°
40°
50°
Latitude/longitude Elevation
Avg. ann. temperature Ann. temperature range Ann. precipitation Population
Concepción, Bolivia
16° 15´ S 62° 03´ W
490 m
23°C
6.5 C° 1212 mm 10 000
La Paz, Bolivia
16° 30´ S 68° 10´ W
4103 m
11°C
3.5 C°
555 mm
810 300 (Administrative division 1.6 million)
▲Figure 5.6 Effects of latitude and elevation. [(b) Peter langer/Design Pics/Corbis. (c) Seux Paule/age Fotostock.]
before dawn, the coldest time of the day. At night, clouds act as an insulating layer that reradiates longwave energy back to Earth, preventing rapid energy loss to space. Thus, in general, the presence of clouds raises minimum night- time temperatures. During the day, clouds reflect insola- tion, lowering daily maximum temperatures; this is the familiar shading effect you feel when clouds move in on a hot summer day. Clouds also reduce seasonal temperature differences as a result of these moderating effects.
Clouds are the most variable factor influencing Earth’s radiation budget, and studies are ongoing as to their effects on Earth’s temperatures. For more in- formation, read about the Global Energy and Water Cycle Experiment (GEWEX) at www.gewex.org/gewex_ overview.html#foci, or check out NASA’s Clouds and the
Earth Radiant Energy System (CERES) experiment at ceres.larc.nasa.gov/.
Land–water Heating Differences
An important control over temperature is the difference in the ways land and water surfaces respond to insolation. On Earth, these two surfaces occur in an irregular arrange- ment of continents and oceans. Land and water absorb and store energy differently, with the result that water bodies tend to have more moderate temperature patterns, whereas continental interiors have more temperature extremes.
The physical differences between land (rock and soil) and water (oceans, seas, and lakes) are the reasons for land–water heating differences, the most basic of which
(c) High-elevation villages near La Paz are in view of permanent ice-covered peaks of the Bolivian Cordillera Real in the Andes Mountains.