Environmental Engineering Reference
In-Depth Information
westerlies in temperate latitudes. Away from Earth's surface the winds strengthen,
particularly in temperate and polar latitudes. The upper westerlies flow in a series of
waves, called Rossby waves, which have a major effect on surface weather conditions.
3
Long-distance interactions within the atmosphere do occur. Periodic changes in ocean
and atmospheric circulations in the south-east Pacific can have an effect on the
weather across much of the southern hemisphere.
CONCLUSION
Atmospheric movements, together with oceanic circulation, are the main processes by
which energy is transferred through the global system. They act to maintain a steady state
in the system by transporting excess energy from areas which receive high inputs of solar
radiation to areas where inputs are small. Such movements involve two general patterns
of flow: the predominantly zonal flow of air within the main wind belts and the less
apparent but even more important meridional transfers. Both circulations are controlled
by the pressure gradient force, which acts as the driving force of atmospheric motion.
Earth's rotation, acting through the Coriolis force, and friction modify the simple pattern
of circulation initiated by the pressure gradient force to give the complex systems we find
in the atmosphere.
These atmospheric movements are vital for a number of reasons. Many of the features
of the world's climates are dependent upon the character of atmospheric circulation, as
we shall see in Chapter 7. Seasonal and daily variations in the circulation affect our lives
directly, and extreme events may have a dramatic impact on humanity, topics which will
be covered in Chapters 24-8.
FURTHER READING
Ahrens, D. L. (2000)
Meteorology Today
, sixth edition, Minneapolis, MN: West Publishing
(chapter 9). Visual and elementary approach to aspects of winds and factors controlling airflow.
Atkinson, B. W. (1981)
Dynamical Meteorology
, London: Methuen. Based on articles published in
Weather by the Royal Meteorological Society, this topic describes the complex issues of
atmospheric movement in as non-mathematical a way as possible. Still not easy for the non-
mathematician.
Barry, R. G., and Chorley, R. J. (1998)
Atmosphere, Weather and Climate
, seventh edition,
London: Routledge (chapters 5 and 6). Serious attempt to explain and inform about the controls
of atmospheric motion. Covers a wide range of scales of motion, from micro to global.
