Geoscience Reference
In-Depth Information
1
CHAPTER ONE
Introduction and history
of meteorology and
climatology
LEARNING OBJECTIVES
When you have read this chapter you will:
n
be familiar with key concepts in meteorology and climatology
n
know how these fields of study evolved and the contributions of leading individuals.
most had a long and complex evolution. A
thermometer was invented by Galileo in the early
1600s, but accurate liquid-in-glass thermometers
with calibrated scales were not available until the
early 1700s (Fahrenheit), or 1740s (Celsius). In
1643 Torricelli invented the barometer, and
demonstrated that the weight of the atmosphere
at sea level would support a 10m column of
water or a 760mm column of liquid mercury.
Pascal used a barometer of Torricelli to show that
pressure decreases with altitude, by taking one up
the Puy de Dome in France. This paved the way
for Boyle (1660) to demonstrate the compress-
ibility of air by propounding his law that volume
is inversely proportional to pressure. It was not
until 1802 that Charles made the discovery that
air volume is also directly proportional to its
temperature. Combining Boyle's and Charles'
laws yields the ideal gas law relating pressure,
volume and temperature, one of the most
important relationships in atmospheric science.
By the end of the nineteenth century the four
major constituents of the dry atmosphere
A THE ATMOSPHERE
The atmosphere, vital to terrestrial life, envelops
the earth to a thickness of only 1 percent of the
earth's radius. It had evolved to its present form
and composition at least 400 million years ago by
which time a considerable vegetation cover had
developed on land. At its base, the atmosphere rests
on the land and ocean surface, the latter which, at
present, covers some 71 percent of the surface of
the globe. Although air and water share somewhat
similar physical properties, they differ in one
important respect - air is compressible, while
water is largely incompressible. In other words, in
contrast to water, if one were to 'squeeze' a given
sample of air, its volume would decrease. Study
of the atmosphere has a long history involving
observations, theory, and, since the 1960s,
numerical modeling. Like most scientific fields,
incremental progress has been interspesed by
moments of great insight and rapid advance.
Scientific measurements only became possible
with the invention of appropriate instruments;
