Environmental Engineering Reference
In-Depth Information
Plate 11.3
A wave train entering a bay, showing refraction as
the waves are retarded along its flanks before shoaling
(breaking), with spilling and surging breakers.
Photo: Ken Addison.
ECONOMIC ACTIVITY AND OCEAN-ATMOSPHERE INTERACTIONS
human impact
Coupled ocean-atmosphere systems such as ENSO and the NAO have significant
impacts on human lives.
The short-term, sub-climatic oscillation referred to as
El Niño
occurs at two- to ten-
year intervals around Christmas, hence its Hispanic name 'The Christ Child'. South-east
trade winds relax for some weeks as they cross the Pacific equator, allowing the
westward Equatorial counter-current to flow back unhindered to the Peruvian coast. It
displaces the cold upwelling Peruvian current, triggering major weather disturbances
along the normally dry coastline (and much farther afield), with catastrophic losses in the
anchovy fishing industry, which the current feeds. Climatic consequences are discussed
further in Chapter 6. ENSO events may also trigger changes in the NAO through
coupling of the equatorial Pacific and Atlantic Ocean atmospheres.
Future trends in North Atlantic ocean-atmosphere coupling are one of the more
uncertain aspects of global environmental futures. Simple western European implications
of atmospheric warming would appear to extend Mediterranean climates farther north,
eliminate Alpine glaciers and provide opportunities for arable farming in northern
