Geography Reference
In-Depth Information
upper layers, which are of minor interest to physical geographers.
Botanists, zoologists, and ecologists investigate the biosphere; and
pedologists, hydrologists, glaciologists, and others specialize in
the other spheres mentioned above. What differentiates physical
geography from these other scientifi c fi elds is the focus on spatial
patterns in the landscape and their underlying dynamics from
local, through regional, up to global scales. Local-scale patterns
include, for example, hillslope form and the shapes of valleys,
meandering rivers, woodland distribution, and urban climate.
At regional scales, mountain ranges, major river basins, and
climatic zones come to prominence; whereas at the global scale,
global warming, deforestation and the loss of biodiversity, and
interactions within the Earth-ocean-atmosphere system, are
amongst the topics investigated.
Physical geographers investigate not only variation from place
to place in the various spheres but also the interactions between
the different spheres and their changes through time. El Niño
events provide a good example of interactions at several scales in
space and time. Named after the warm El Niño ocean current that
appears off the coast of Ecuador and northern Peru just
after Christmas, these periodic events begin in the tropics with
intense warming of the surface waters of the equatorial Pacifi c
Ocean and are propagated around the globe producing worldwide
effects. Typical effects of an El Niño event in the northern
hemisphere winter are mapped in Figure 5. They include
droughts in Indonesia, eastern Australia, and southern Africa,
while severe storms and fl ooding occur along the coast of
Ecuador and Peru, and throughout the Gulf States of North
America.
Although physical geography is defi ned by its emphasis on spatial
patterns and spatial processes in the geo-ecosphere, human
activity also plays a major role. The thin, surface 'skin' of planet
Earth is the natural environment on which the human species is
partially, if not entirely, dependent. What distinguishes humans
