Environmental Engineering Reference
In-Depth Information
from the tropics towards the poles, and in so
doing serve to counteract the imbalance.
they carry warm water polewards, in others, they
carry cooler water into lower latitudes (see Figure
2.7). In addition, density differences, in part
thermally induced, cause horizontal and vertical
movement of water within the oceans. All of these
processes help to transfer excess heat from
equatorial regions towards the poles. This is
illustrated particularly well in the North Atlantic,
where the warm waters of the Gulf Stream Drift
ensure that areas as far north as the Arctic Circle
are anomalously mild during the winter months.
The amount and rate of energy transfer varied
in the past, producing significant climatological
effects. Changes in the North Atlantic circulation,
for example, may have contributed to the Ice
Ages. Current estimates of poleward energy
transfer in the northern hemisphere indicate that
ocean transfer exceeds atmospheric transfer in
OCEANIC AND ATMOSPHERIC
CIRCULATION PATTERNS
The circulation of the oceans
More than half of the solar radiation reaching
the earth's surface is absorbed by the oceans,
where it is stored and redistributed, before being
released back into the atmosphere. Ocean and
atmosphere are quite intimately linked. The
prevailing winds in the atmospheric circulation,
for example, drive water across the ocean surface
at speeds of less than 5 km per hour, in the form
of broad, relatively shallow drifts. In some cases,
Figure 2.7 The circulation of the oceans
Search WWH ::




Custom Search