6
Chapter 1: The Development of Climate Research
tain stations in the Alps a.nd in the Rocky Mounatain started to show that
the vertical temperature profile of a storm was more complicated, the theory
was under attack. The evidence brought forward by Julius Hann, director
of the newly formed Austrian Weather Service, caused an uproar. Hann was
violently attacked by Ferrel and the dust did not settle until F .H. Bigelow
suggested that storms were in fact connected to the general circulation. After
1900 a number of studies were able to find out that storms go through a "life
cycle" from N orth America to Europe and their energy budget and dynamical
properties are changing through the various stages of their evolution. This
concept was finally synthesized in a consistent scheme by the so called polar
front theory of cyclones in the 1920. The full story of the understanding of
storms in the XIX century is described in detail in a wonderful monograph
by G. Kutzbach (1979). But it was not until the late 1940's that the first
consistent dynamical interpretation of the polar front cyclones, the baroclinic
instability theory, was discovered by Jules Charney. Meanwhile, other studies were gathering evidence of other large scale patterns on an even larger
scale.
1.1.2 The Great Planetary Oscillations
The research of the XIX century concentrated on storms for good practical
reasons. The motivations for the research at that time were found in the need
to provide ship's captains with some tool to make sense of the behaviour of
the atmosphere and the oceans, with the double aim of avoiding calamitous
storms and deftly exploiting swift winds. This necessity led meteorology
to recognize the fact that American and European storms were part of the
same phenomena, weather patterns connected together on time scales of days
and weeks. The interest for this short time scale was so overwhelming that
relatively little effort was made to discover connections on different time and
spatial scales.
However, in the 1920's and 1930's, Sir Gilbert Walker, the Director of the
Indian Meteorogical Office, devoted hirnself to the study of statistical connections between atmospheric variables over large space scales and long periods
of time. Sir Gilbert was motivated by the puzzle of the Indian monsoon and
its remarkable regularity. A shift of a few weeks in the appearance of the
rains would mean the difference between famine and a good crop for the Indian sub-continent. His approach was to try to find relations between time
series of monthly means of press ure obervations at different places, in the
hope that signs that could anticipate the monsoon would be evident in the
large scale pressure pattern. Working with his colleague Bliss (Walker and
Bliss, 1932), he was able to discover through this analysis that surface pressure was in phase and out of phase in severallocations on the globe, resulting
in broad oscillatory features. Two of these "oscillations" were remarkable,
the Southern Oscillation (SO) and the North Atlantic Oscillation (NAO).
The Southern Oscillation shows up as an out of phase relation between
Chapter 1: The Development of Climate Research
tain stations in the Alps a.nd in the Rocky Mounatain started to show that
the vertical temperature profile of a storm was more complicated, the theory
was under attack. The evidence brought forward by Julius Hann, director
of the newly formed Austrian Weather Service, caused an uproar. Hann was
violently attacked by Ferrel and the dust did not settle until F .H. Bigelow
suggested that storms were in fact connected to the general circulation. After
1900 a number of studies were able to find out that storms go through a "life
cycle" from N orth America to Europe and their energy budget and dynamical
properties are changing through the various stages of their evolution. This
concept was finally synthesized in a consistent scheme by the so called polar
front theory of cyclones in the 1920. The full story of the understanding of
storms in the XIX century is described in detail in a wonderful monograph
by G. Kutzbach (1979). But it was not until the late 1940's that the first
consistent dynamical interpretation of the polar front cyclones, the baroclinic
instability theory, was discovered by Jules Charney. Meanwhile, other studies were gathering evidence of other large scale patterns on an even larger
scale.
1.1.2 The Great Planetary Oscillations
The research of the XIX century concentrated on storms for good practical
reasons. The motivations for the research at that time were found in the need
to provide ship's captains with some tool to make sense of the behaviour of
the atmosphere and the oceans, with the double aim of avoiding calamitous
storms and deftly exploiting swift winds. This necessity led meteorology
to recognize the fact that American and European storms were part of the
same phenomena, weather patterns connected together on time scales of days
and weeks. The interest for this short time scale was so overwhelming that
relatively little effort was made to discover connections on different time and
spatial scales.
However, in the 1920's and 1930's, Sir Gilbert Walker, the Director of the
Indian Meteorogical Office, devoted hirnself to the study of statistical connections between atmospheric variables over large space scales and long periods
of time. Sir Gilbert was motivated by the puzzle of the Indian monsoon and
its remarkable regularity. A shift of a few weeks in the appearance of the
rains would mean the difference between famine and a good crop for the Indian sub-continent. His approach was to try to find relations between time
series of monthly means of press ure obervations at different places, in the
hope that signs that could anticipate the monsoon would be evident in the
large scale pressure pattern. Working with his colleague Bliss (Walker and
Bliss, 1932), he was able to discover through this analysis that surface pressure was in phase and out of phase in severallocations on the globe, resulting
in broad oscillatory features. Two of these "oscillations" were remarkable,
the Southern Oscillation (SO) and the North Atlantic Oscillation (NAO).
The Southern Oscillation shows up as an out of phase relation between