Section 1.1: The Nature of Climate Studies
5
for elaborating new methods for studying and eventually predicting storms.
The main problem in those times was to make sense of the complication of
the winds and current behaviour to try to isolate some generalization, some
pattern or some simple dynamicallaw.
In general terms, these efforts were aiming at identifying and isolating
patterns in the observed data. The invention of the synoptic map (1860)
contributed to the search for physical phenomena that could be identified as
a recurrent feature of the weather. Storms were the most immediate phenomena to be studied and also one whose practical importance was enormous.
Great effort was therefore put in trying to define and understand the patterns
of wind, pressure and rain, collectively known as "storms".
The main controversy that occupied the XIX century meteorologists had
to do with the nature and origin of "storms". In the beginning of the century, before synoptic charts were invented, there were wild disagreements on
the nature of storms and particularly intense was the controversy between
Americans and European researchers on the rotational nature of the wind in
storms. It was weIl known at that time that storms were characterized by
surface low pressure, but the relation between pressure and wind was a little
sketchy. Some people, like the famous and powerful German meteorologist
H. Dove, refused the idea of rotary storms altogether and theorized that the
meteorological events observed as storms were merely the displacement of
tropical currents with polar currents and vi ce versa. Dove's law of gyration
of winds ("Drehungsgesetz" ) that describes how the winds shift during the
transition between the two currents was commonly used in Europe until the
1860's. On the other hand, in the United States, observations by W. C.
Redfield seemed to support very strongly the rotational character of storms.
From a modern point of view the controversy was fueled by the total confusion about the physical phenomena to be explained. There was no attempt
to distinguish between storms of different scales and there was no attempt to
separate storms between midlatitude cyclones and tropical cyclones. In fact,
Dove's observations in central Europe were actually south of the predominant
path of the low pressure center, making it difficult to realize the rotation al
movement of the cyclone, whereas Redfield mOStlY focused on hurricanes and
tornadoes, whose rotational character was immediate.
An alternative explanation of storms was offered by J .P. Espy in 1841.
In the late 1870's it became the accepted scientific theory for the scientific
understanding of storms. Espy identified the condensation process of water
vapor as the main energy sour ce for the storms. In his theory the circulation
inside a storm was to be directed towards the low pressure center where the
vertical motion would produce enough condensation to sustain energetically
the circulation.
Essential for Espy's theory was the vertical profile of temperature in the
storm. In Espy's vision, cyclones were cold and anticyclones were warm air
vortices with no vertical structure, so when upper air observations at moun-
5
for elaborating new methods for studying and eventually predicting storms.
The main problem in those times was to make sense of the complication of
the winds and current behaviour to try to isolate some generalization, some
pattern or some simple dynamicallaw.
In general terms, these efforts were aiming at identifying and isolating
patterns in the observed data. The invention of the synoptic map (1860)
contributed to the search for physical phenomena that could be identified as
a recurrent feature of the weather. Storms were the most immediate phenomena to be studied and also one whose practical importance was enormous.
Great effort was therefore put in trying to define and understand the patterns
of wind, pressure and rain, collectively known as "storms".
The main controversy that occupied the XIX century meteorologists had
to do with the nature and origin of "storms". In the beginning of the century, before synoptic charts were invented, there were wild disagreements on
the nature of storms and particularly intense was the controversy between
Americans and European researchers on the rotational nature of the wind in
storms. It was weIl known at that time that storms were characterized by
surface low pressure, but the relation between pressure and wind was a little
sketchy. Some people, like the famous and powerful German meteorologist
H. Dove, refused the idea of rotary storms altogether and theorized that the
meteorological events observed as storms were merely the displacement of
tropical currents with polar currents and vi ce versa. Dove's law of gyration
of winds ("Drehungsgesetz" ) that describes how the winds shift during the
transition between the two currents was commonly used in Europe until the
1860's. On the other hand, in the United States, observations by W. C.
Redfield seemed to support very strongly the rotational character of storms.
From a modern point of view the controversy was fueled by the total confusion about the physical phenomena to be explained. There was no attempt
to distinguish between storms of different scales and there was no attempt to
separate storms between midlatitude cyclones and tropical cyclones. In fact,
Dove's observations in central Europe were actually south of the predominant
path of the low pressure center, making it difficult to realize the rotation al
movement of the cyclone, whereas Redfield mOStlY focused on hurricanes and
tornadoes, whose rotational character was immediate.
An alternative explanation of storms was offered by J .P. Espy in 1841.
In the late 1870's it became the accepted scientific theory for the scientific
understanding of storms. Espy identified the condensation process of water
vapor as the main energy sour ce for the storms. In his theory the circulation
inside a storm was to be directed towards the low pressure center where the
vertical motion would produce enough condensation to sustain energetically
the circulation.
Essential for Espy's theory was the vertical profile of temperature in the
storm. In Espy's vision, cyclones were cold and anticyclones were warm air
vortices with no vertical structure, so when upper air observations at moun-