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Who
Discovered the El Niño-Southern
Oscillation?
Gregory T. Cushman
Department of History
Southwestern University, Georgetown, TX
cushmangreg@yahoo.com
ABSTRACT: Two giants
of 20th-century meteorology, Gilbert Walker and Jacob
Bjerknes, are usually given credit for discovering the El
Niño-Southern Oscillation phenomenon. During the
early 1920s, Walker empirically identified a periodic
variation in atmospheric pressure over the Indo-Pacific
which he christened the "Southern Oscillation." During the
1960s, Bjerknes posited a physical mechanism to explain the
atmospheric features of this phenomenon over the equatorial
Pacific which he christened the "Walker Circulation." Both
men deserve recognition since they opened the way for our
present understanding of the global climate system.
But meteorology consists of more than brute number crunching
and elegant physical reasoning. These two giants should
share credit with others who identified important features
of this phenomenon--none of whom were meteorologists. Three
Americans: Robert Cushman Murphy, T. Wayland Vaughan, and
Milner Bailey Schaefer deserve recognition for organizing a
trans-Pacific network of interested scientists in the late
1920s and late 1950s. Schaefer, in fact, paid Bjerknes to
study the "El Niño" problem in order to predict
variations in Pacific tuna distribution. Three German
oceanographers: Gerhard Schott, Erwin Schweigger, and Klaus
Wyrtki deserve recognition for interpreting oceanic features
of this phenomenon.
Credit for any scientific discovery automatically entails a
subjective value judgment of what counts as new
understanding. The basis for such judgments changes over
time. Some scientists deserve credit for "discovering" the
El Niño-Southern Oscillation, even though they were
motivated by beliefs we now consider wrong-headed.
In 1877, the Chilean Benjamin Vicuña MacKenna
immediately recognized the link between climate anomalies
all over the Pacific basin--because they corresponded with a
powerful tsunami. During the early 1890s, two Peruvian
scientists used "rustic astronomy" to interpret anomalies
along the arid Peruvian coast. Using information from local
fisherfolk, Camilo Carrillo adopted the term "El Niño
countercurrent"--the origin of our name for a much larger
phenomenon--to describe periodic variations in the Humboldt
(Peru) Current. Victor Eguiguren compiled a rough
chronology of rainy seasons in northern Peru to prove this
region was becoming wetter over time. Beginning in the
1920s, the Dutch-colonial scientist H.P. Berlage, Jr. turned
Walker's Southern Oscillation into a usable, potentially
predictive concept. He may have been the first to recognize
its direct connection with oceanic features off the coast of
Peru. His contribution is often discounted, however,
because it was intended to bolster the discarded theory that
most interannual atmospheric variation is tied to solar
cycles.
The work of these four men is important to scientists
working today for another reason. William H. Quinn
fundamentally based his famous chronology of the El
Niño-Southern Oscillation on their work. Despite his
best efforts, Quinn's chronology contains artifacts of the
discarded theories these scientists were trying to prove.
Historians of science can thus provide a major service to
working climatologists, not by deciding which scientists
deserve the most credit for a discovery, but by showing how
the values of climatologists have changed over time and how
this change has itself influenced our current
understanding.
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What
Role Did G.S. Callendar Play in Reviving the CO2 Theory of
Global Climate Change?
James Rodger Fleming
Science, Technology and Society Program
Colby College
Waterville, ME 04901
jrflemin@colby.edu
ABSTRACT: In 1938,
Guy Stewart Callendar, a noted British steam engineer,
published "The Artificial Production of Carbon Dioxide and
Its Influence on Temperature," the first of many articles
aimed at reviving the carbon dioxide theory of climate
change. Callendar took his own weather observations at his
home in Sussex and compiled a massive amount of temperature
data from around the world. Noting an upward trend in
temperatures for the first four decades of the twentieth
century, he combined these results with studies of the
retreat of glaciers, measurements of rising concentrations
of atmospheric carbon dioxide since pre-industrial times,
and information newly available concerning the infrared
absorption bands of atmospheric constituents. He concluded
that the trend toward higher temperatures was significant,
especially north of the forty-fifth parallel; that increased
use of fossil fuels had caused a rise of the concentration
of CO2 in the atmosphere of about ten percent from
nineteenth century levels; and that increased sky radiation
from the extra CO2 was linked to the rising temperature
trend.
Although he was an amateur meteorologist, Callendar worked
on a truly global scale, compiling a reliable world data set
of surface temperatures from earliest times and
insisting&emdash; long before it became fashionable to do
so&emdash;that climatology must deal with physics and
atmospheric dynamics. Even in the depths of World War II
Callendar remained active in climate research, publishing
two papers while working on technical problems (including
infrared absorption) with the Ministry of Supply. In 1944
climatologist Gordon Manley noted Callendar's valuable
contributions to the study of climatic change. A decade
later, Gilbert Plass and Charles Keeling consulted with
Callendar before beginning their research programs. Just
before the beginning of the IGY, Hans Seuss and Roger
Revelle referred to the "Callendar effect," defined as
climatic change brought about by anthropogenic increases in
the concentration of atmospheric carbon dioxide, primarily
through the processes of combustion.
Until recently, Callendar has been a neglected figure in the
history of science. Now, his correspondence with such
notables as Hubert Lamb, J. Murray Mitchell, Helmut
Landsberg, and others mentioned above, and some ninety-five
of his notebooks, held at the University of East Anglia,
have been preserved, indexed, scanned, and are being made
available to researchers as digital images. These documents
contain data, charts, notes, reviews, and many candid
insights into the state of climate science between 1936 and
1964. This collection is being supplemented by a set of
Callendar's complete published works and by research in
other archival repositories that will help provide a more
complete account of the life and work of this most
remarkable and dynamic climatologist.
ACKNOWLEDGMENT: This work
has been supported by the National Science Foundation under
Grant No. SES-0114998 and by an Interdisciplinary Studies
Division research grant from Colby College.
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How
did Scandinavian Visitors to the U.S. Contribute to NWP
Development?
Kristine Harper
Oregon State University
Corvallis, OR 97330
harper@proaxis.com
ABSTRACT: In late
1945, the distinguished mathematician John von Neumann
needed a suitably difficult scientific problem amenable to a
numerical solution to showcase the capabilities of his
proposed computer. Although there were numerous candidates
from the physical sciences, von Neumann settled on the
weather prediction problem. In their brief accounts of the
development of numerical weather prediction, William
Aspray's John von Neumann and the Origins of Modern
Computing and Frederik Nebeker's Calculating the Weather:
Meteorology in the 20th Century give von Neumann primary
credit for starting and leading the Meteorology Project at
the Institute for Advanced Study. Given considerably less
credit are Carl-Gustav Rossby, Jule Charney, and a series of
Scandinavian meteorologists who significantly influenced the
entire project. Available U.S. meteorologists were more
likely to have been mathematicians and physicists trained in
meteorology as a result of World War II. They had the
technical background to support numerical modeling, but were
lacking in a subjective feel for the atmosphere. Those who
did have extensive forecasting backgrounds were likely not
to have the required theoretical background to meet the
needs of the project. The Scandinavians, however, were not
only theoretically grounded; they also had a solid feel for
the atmosphere. I will argue that the Scandinavian
"tag-team," invited by Charney and supported by Rossby, was
not only critical to the ultimate success of the Meteorology
Project, but that differences in the cultures of meteorology
in the United States and Scandinavia made the Scandinavians
better suited to accomplish the work which would enable them
to answer this question: Is the computer predicted
representation of the atmosphere a valid one?
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How
has the Original Franklin Rod Evolved into Today's Lightning
Protection System?
E. Philip Krider
Institute of Atmospheric Physics
The University of Arizona
Tucson, AZ 85721-0081
krider@atmo.arizona.edu
ABSTRACT: The
Philadelphia experiments and observations on static
electricity, as led and communicated by Benjamin Franklin,
were important because some were new and novel and because
their interpretations helped to stimulate the development of
electricity as a science and the beginnings of modern
physics. This work also led to the famous sentry box and
kite experiments that proved once and for all that
thunderclouds are electrified and that lightning is an
electrical discharge. The latter discoveries, in turn,
validated the key assumptions that lay behind Franklin's
supposition that tall, grounded rods might protect
structures from lightning damage. Here, we will trace how
Franklin's ideas about "the wonderful effects of pointed
bodies" evolved into the design of the first protective
rods, and then we will describe some important improvements
that Franklin made to this design in the years from 1752 to
1762, after experience was gained through practice. Today,
most authorities agree that the main functions of a
lightning rod and the associated conductors are to define
and control the points where lightning will attach to a
structure and then to provide safe paths for the current to
flow to ground. In a letter written in 1762, Franklin noted
that "Indeed, in the construction of an instrument so new,
and of which we could have so little experience, it is
rather lucky that we should at first be so near the truth as
we seem to be, and commit so few errors." Lucky indeed -
today virtually every lightning protection code in the world
still recommends grounded metallic rods for protecting
ordinary structures, and the basic elements of their design
and installation are, in essence, the same as Franklin's
specifications of 1762.
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What
were the scientific implications of Military support for
Upper-air Research on Radio Wave Propagation in the
1940s?
John Wedge
Department of History
University of Illinois
Champaign-Urbana IL 61820
wedge@students.uiuc.edu
ABSTRACT: In the
years from 1941 onwards, first during wartime and then as
part of the burgeoning Cold War, the United States sought to
develop its capabilities of command, control and integration
by extending the reach of its radiocommunication network to
encircle the world. Communications over distances so great
that the wave had to be guided by the ionosphere were of
major importance to both sides during World War II. These
difficulties of radio wave propagation, and in predicting
the dynamics of the upper atmosphere, made the ionosphere
unreliable as a resource to utilise. Commencing immediately
after the attack on Pearl Harbor, the US military organised
for the construction of a network of research stations to
map the ionosphere in an effort to better understand it.
Coordinated internationally between the wartime Allies, and
centered around the National Bureau of Standards Radio
Section and the Division of Terrestrial Magnetism at the
Carnegie Institution of Washington, an unprecedented program
was launched to analyse ionospheric radiowave propagation
and the upper atmosphere across the globe. The aim of this
program was to create a comprehensive and systematic set of
data from which projections of ionospheric activity could be
made, and through which the ionosphere could be rendered
more stable and predictable.
While the military's needs were transparent, the
implications of this program for science were less so. The
secret research program and its classified results found
their analogy in an opaque set of value changes that
underlay the scientific work conducted on the military
payroll. This research signified an important change of
emphasis and shift in direction for studies of the upper
atmosphere. Since no sampling was possible above balloon
altitude, from 1924 onwards research had focused on the use
of radio sounding techniques. Teams headed by Edward
Appleton and J.A. Ratcliffe, Merle Tuve and Gregory Briet,
and E.O. Hulburt at the Naval Research Laboratory collected
data on the electron content of the upper atmosphere by
studying radio wave echoes that were reflected back from a
vertical transmission. As a result, prior to 1940
significant gains had been made in upper atmosphere
research, particularly in the appreciation of the nature of
the medium at altitudes above the troposphere. The
trajectory of these researches, although earthbound
observations using remote sensory equipment, followed a
model of classical scientific study. Even relying on remote
interaction with the phenomena under study the key questions
concerned the state of the atmosphere, its chemistry and
physics, its consistency and composition. While the
question of properties remained central, driven by the
exigencies of Military requirements and their need for
tools, this new research initiative was driven rather by
considerations of behaviour.
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