Geoscience Reference
In-Depth Information
1
Introduction and history of meteorology
and climatology
Learning objectives
When you have read this chapter you will:
Be familiar with key concepts in meteorology and climatology,
Know how these fields of study evolved and the contributions of leading individuals.
A THE ATMOSPHERE
decreases with altitude, by taking one up the Puy de
Dôme in France. This paved the way for Boyle (1660)
to demonstrate the compressibility of air by propound-
ing his law that volume is inversely proportional to
pressure. It was not until 1802 that Charles showed that
air volume is directly proportional to its temperature.
By the end of the nineteenth century the four major
constituents of the dry atmosphere (nitrogen 78.08 per
cent, oxygen 20.98 per cent, argon 0.93 per cent and
carbon dioxide 0.035 per cent) had been identified.
In the twentieth century it became apparent that CO
2
,
produced mainly by plant and animal respiration and
since the Industrial Revolution by the breakdown of
mineral carbon, had changed greatly in recent historic
times, increasing by some 25 per cent since 1800 and by
fully 7 per cent since 1950.
The hair hygrograph, designed to measure relative
humidity, was only invented in 1780 by de Saussure.
Rainfall records exist from the late seventeenth century
in England, although early measurements are described
from India in the fourth century
BC
, Palestine about
AD
100 and Korea in the 1440s. A cloud classification
scheme was devised by Luke Howard in 1803, but was
not fully developed and implemented in observational
The atmosphere, vital to terrestrial life, envelops the
earth to a thickness of only 1 per cent of the earth's
radius. It had evolved to its present form and com-
position 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 ocean
surface which, at present, covers some 70 per cent of
the surface of the globe. Although air and water share
somewhat similar physical properties, they differ in one
important respect - air is compressible, water incom-
pressible. Study of the atmosphere has a long history
involving both observations and theory. Scientific
measurements became possible only with the invention
of appropriate instruments; 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 the 1740s
(Celsius). In 1643 Torricelli demonstrated that the
weight of the atmosphere would support a 10 m column
of water or a 760 mm column of liquid mercury. Pascal
used a barometer of Torricelli to show that pressure
