Geoscience Reference
In-Depth Information
Figure 17-3. MODIS image of western Venezuela and northeastern Colombia. Segments of the Andes Mountains: 1.
Sierra Nevada de Santa Marta, 2. Sierra de Perijá, 3. Cordillera de Mérida. Acquired 7 January 2003 during the dry
winter season; adapted from visible-color image of NASA
<
http://visibleearth.nasa.gov/
>
.
Figure 17-4. Rare, nearly cloud-free satellite image of Andes region in western Venezuela (see Color Plate 17-4). Bright
green indicates evergreen and deciduous forest; dark olive-green is alpine shrub of the páramo. Landsat MSS bands 1, 4
and 2 color coded as blue, green and red. Acquired 13 January 1979. Image from NASA; processing by J.S. Aber.
and high peaks, topographic relief ranges from
less than 1000 m elevation along the Río Chama
valley below the city of Mérida to above 5000 m
on Pico Bolívar (Fig. 17-4). This great range of
elevations over short distances gives rise to dra-
matic variations in local climate, vegetation,
wildlife, geomorphic processes, and human land
use (Fig. 17-5; Ruiz 1992).
Distribution of precipitation is controlled
strongly by elevation and prevailing wind. Most
precipitation falls on the southeastern side of
the major mountain ridge located to the south-
east of Mérida. Annual precipitation exceeds
2.8 m in this zone; whereas the Río Chama valley
generally has less than 1 m annual precipitation
(Ruiz 1992). Summer is the rainy season, and
Search WWH ::




Custom Search