1. North-South Variations in West Coast
Hydrometeorological Parameters and
Their Significance for Earth Systems
Richard G . Lawford
Terrestrial processes coupled with atmospheric processes control the
hydrological and biological characteristics of the western coasts of North
and South America. Asymmetries exist between these two coasts in the
distribution, richness, and diversity of biota. To some extent , these differences are a residual of the history of the two continents. They are also
a function of the geomorphology and climate that control energy flows
through ecosystems in these areas. An important question for the peoples
of these regions, whose economies are derived from the local natural
resources, relates to both the current rate of natural change and the
sensitivity of these systems to anthropogenically driven changes that may
result from local and global resource development . An understanding of
the present is a key to predicting the future . Accordingly, we focus in
this chapter on hydrometeorological controls, on existing ecosystems,
with a view to identifying those aspects that may be most subject to
change in the future.
Coastal mountains and the Pacific Ocean exert strong influences on
atmospheric circulation patterns and on the climate and hydrology of the
western coasts of the two continents. The similarities between the two
coasts are unique and are not duplicated in either the central areas or the
eastern coasts of the two continents, nor on any other pair of continents.
The similarities in the gross features along the two coasts of the wind,
ocean-current, and radiation patterns make the climate and hydrology
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