Physics Meets Meteorology

While meteorologists had been forecasting the weather, a very small number of scientists, mostly physicists, had been developing theories to explain the formation of cyclones areas of counterclockwise turning air associated with low air pressure and stormy conditions. (Cyclones turn clockwise in the Southern Hemisphere.) By 1900, theories of cyclonic development, life, and death depended on the principle of energy conservation. The first law of thermodynamics, in particular, relates the...

Measuring Initial Conditions

Margules's and Bjerknes's ideas depended very heavily on one thing timely, accurate data collected from all atmospheric levels. This was a very complicated problem for a number of reasons. Scholars had observed the atmosphere in a systematic way since at least the time of Aristotle, but these observations were qualitative until the time of the Scientific Revolution (ca. 1550 to 1700). Qualitative observations gave relative information about temperature (hot or cold), wind (very windy or calm),...

Introduction

Weather and climate two subjects that many people think they know a lot about. Humans have been wondering and complaining about the weather, bad weather in particular, since they first walked on the face of the Earth. Perhaps it was this very familiarity with weather and climate that prevented these areas of study from being considered part of mainstream science until the middle of the 20th century. This book traces the fascinating and often frustrating history of the transformation of the...

Info

Ing of atmospheric processes, more detailed and widely distributed observational data, and faster computers. The National Meteorological Center (National Weather Service) was producing wind and temperature forecasts at six levels in the atmosphere with a horizontal resolution of 186 miles (300 km) (the distance between data grid points), as were the U.S. Navy and Air Force. Research models, being run by the Geophysical Fluid Dynamics Laboratory (GFDL) in Princeton, New Jersey, and by the...

Crunching the Numbers

By the early 1970s, numerical weather prediction (NWP) had become more sophisticated. Weather services around the world were using In 1973, 13 European nations joined to create the European Centre for Mid-Range Weather Forecasting (ECMWF), one of the world's major weather prediction centers, in Reading, England. (ECMWF) In 1973, 13 European nations joined to create the European Centre for Mid-Range Weather Forecasting (ECMWF), one of the world's major weather prediction centers, in Reading,...

Climate Change Heating Up or Cooling Down

Meteorological developments in the 1970s both practical and theoretical were primarily due to improvements in computer capacity, which allowed modelers to include more atmospheric variables. Improvements in remote sensing devices, especially satellites and weather radar, improved meteorologists' ability to track storm systems and to collect more data in smaller time increments over wider geographic areas. As a result, routine and tropical predictions continued to improve and cover longer...

Further Reading

Tornado Alley Monster Storms of the Great Plains. Oxford Oxford University Press, 1999. The tornado expert and chaser Bluestein shares his love of tornadoes and the science behind them. Heavy rains triggered by an El Ni o event led to flooding in Rillito Creek, Tucson, Arizona, that caused substantial damage in October 1983. (USGS) Bluestein, Howard B. Tornado Alley Monster Storms of the Great Plains. Oxford Oxford University Press, 1999. The tornado expert and chaser...

Looking at El

Examinations of climate, as well as of weather, were a common feature of this decade. Meteorologists began looking for connections between atmospheric and oceanographic phenomena that might seem unrelated at first glance. One meteorological event that drew increased interest was known as El Ni o. El Ni o is the term used to describe the change in the oceanic current along the coasts of Ecuador and Peru from cold to warm. Translated the Christ Child, El Ni o typically appears around Christmas...

Climate Models Take the Stage

While weather forecasting models were still in their primitive operational stage in the late 1950s, meteorologists moved on to modeling the general circulation of the atmosphere. Although the original intent was to continue the development of atmospheric theory, it soon became evident to those involved that modeling the general circulation would lead to models of climate the long-term manifestation of the weather that depends upon geographical location and local topography. General circulation...

Still Warming Up

Increasing levels of atmospheric CO2 gave credence to the idea that people were the primary cause of warming surface temperatures. While the popular media published articles about weird weather, scientists continued to argue about temperature trends and just what they meant for the future. The geophysicists W. Maurice Ewing (1906-74) and William Donn (1918-87) had proposed that warming would cause the Arctic ice sheet to break up. This event would, they thought, lead to increased precipitation...

The Butterfly Effect

Butterfly Effect Symbol

Numerical weather prediction techniques had continued to improve throughout the 1950s. As computer power grew and meteorologists con- tinued to develop a more sophisticated theory of the general circulation of the atmosphere, numerical modelers designed increasingly complex forecasting models. In fact, it often appeared that computer architecture would prove to be the primary obstacle to accurate short- and long-term weather forecasts. As computers could handle more data and process them...

Eyes in the

Meteorologists have always known that they would have a much easier time forecasting the weather if they could see approaching weather systems. In the early 20th century, they addressed this problem by sending observational data via telegraph to stations downstream to advise them of heavy rain, snow, or wind en route. Knowing the upstream weather did not guarantee it would not change before arrival. Forecasters on coastlines were blind to weather moving in from the oceans because there were no...

Remote Sensing Impacts Weather and Climate Studies

It may have provided low-quality, grainy photographs, but TIROS-1, America's first weather satellite, was a boon to meteorologists and weather forecasters as it provided images of frontal systems and tropical storms at sea, far from surface observation posts. Over the course of the decade, more sophisticated weather satellites were launched, carrying additional sensors to measure global temperatures as well as to provide photographs of clouds. Meteorologists continued to actively research...

The International Geophysical Year

The International Geophysical Year (IGY), which ran from July 1, 1957, through December 31, 1958, was a period of concentrated international scientific cooperation in the spirit of the two International Polar Years (1882-83 and 1932-33). This particular 18-month period was selected because it was the 25th anniversary of the Second International Polar Year and because it would be a period of unusually active solar activity. Although 13 different scientific programs investigated the geophysical...

Scientists of the Decade Participants in International Projects

Unlike many other disciplines, the atmospheric sciences thrive on the international exchange of tens of thousands of observations daily. These observations originate from land stations, drifting buoys, military and merchant ships transiting the oceans, radiosondes, airplane pilots, radar, and satellites. Analyzing all of these observations is a massive undertaking and requires the cooperation of scientists all over the world whether their national governments are allies or not. In the...

Joining Forces to Solve Atmospheric Problems

The need for additional detailed meteorological observations, particularly in the Tropics, spurred the international community to propose a massive multinational effort to gather and evaluate weather data. Organized by the World Meteorological Organization (WMO) and the International Council of Scientific Unions (ICSU), planning began in the 1960s with a target year of 1974 for the Global Atmospheric Research Project (GARP). According to the GARP proposal, The entire atmosphere of the Earth and...

Ozone Dangers

The potential dangers of uncontrolled climate change were joined by yet another possible human-induced problem, high surface ozone concentrations in urban areas and the reduction of stratospheric ozone concentrations. Ozone is a naturally occurring unstable gas that makes up 0.000007 percent of the lower atmosphere (or 0.07 part per million ppm ). It is also created by photochemical reactions when nitrogen oxides produced by motor vehicle exhaust and a variety of hydrocarbons from both human...

Peering into the Past

As climatologists puzzled over current warming or cooling trends, some of their colleagues attempted to reconstruct the record of past climate. This was a difficult task because scientifically accurate meteorological observations taken with high-quality, calibrated instruments had only become available during the previous century. Although scientists are usually uneasy about using proxies, that is, records from which scientific information may be inferred, in this case there were very few...

On the Other Hand A New Ice

Colder Winters Held Dawn of New Ice Age screamed a front page Washington Post headline on January 11, 1970. The Post writer David R. Boldt reported that some climatologists were arguing that Earth had entered a cold period in 1950 and it could last for hundreds of years. In support of this argument, the climatologists noted that the global temperature had dropped 0.6 F (0.33 C) since 1950. If the current rate of decline continued, in 240 years Earth's temperature would be 7.2 F (4 C) lower and...

Cracking Hurricane Secrets

Improved satellite images, advanced computer design, and increasingly sophisticated models all helped atmospheric scientists learn how hurricanes came to be born, live, track across the oceans, and die either a natural death at sea or a violent one when they went ashore. An early hurricane model (HURRAN) predicted a hurricane's potential track by comparing its current atmospheric situation with those of previous hurricanes. The model assumed that if the existing weather pattern had occurred...

Richardsons Weather Factory

English meteorologist Lewis Fry Richardson (1881-1953) was determined to find a mathematical solution for weather forecasting. The son of prosperous Quaker (Society of Friends) parents, Richardson was the superintendent of Scotland's Eskdalemuir Observatory when World War I erupted. A pacifist, Richardson sought a leave of absence to provide noncombat assistance to the war effort. Denied leave, he resigned in 1916, volunteered to be a driver with the Friends' Ambulance Unit, and was assigned to...

Theory Development and Application

In the immediate postwar years, European nations recognized the importance of strong military and civilian aviation programs and devoted financial resources to supporting meteorological services. As Bergen School techniques continued to evolve, European weather services adopted their air mass analysis and frontal theories. Not confined to forecasting the weather, these university-trained meteorologists also conducted extensive atmospheric research. The United States was not so forward-looking....

Perfect Couple Aviation and Meteorology

Hot-air balloons, airships (blimps), and fixed-wing aircraft all operate in the atmosphere. From the time these first flying machines lifted off, the futures of aeronautics and meteorology became inextricably entwined. Observers in 19th-century hot-air balloons collected atmospheric data, but these were not systematic efforts. Once pilots determined that sharing atmospheric data with meteorologists directly enhanced flight safety, a symbiotic relationship developed between aviators and...

Weather on the Front Lines

War erupted in Europe in August 1914, as the German army raced across the plains of France and stopped a few miles short of Paris. In past conflicts, field commanders had not considered the tactical or strategic use of weather information. As the Nobel Prize-winning physicist and U.S. military meteorology coordinator Robert A. Millikan (1868-1953) wrote in his 1919 article Some Scientific Aspects of the Meteorological Work of the United States Army, Prior to 1914 a meteorological section was...

Calculating the Weather

Meteorologists focused on the whys behind the weather at the same time they worked to improve weather forecasts. Advances in aeronautics provided opportunities to gather data at higher altitudes and put pressure on meteorologists to develop upper-level forecasts critical for flight safety. Mid-decade, as war spread across Europe, accurate weather data and forecasts became vitally important to soldiers on the ground and in the air as new war fighting techniques required carefully tailored...

Big Steps in Cloud Physics and Climatology

The decade just prior to the start of World War II saw major advances in two different areas of atmospheric studies, climatology and cloud physics. As in the previous three decades, European scientists led in theoretical and empirical atmospheric research. In the United States, weather forecasting continued to be meteorology's focus. Although the U.S. Weather Bureau finally introduced Bergen School methods into its forecasting repertoire, consistent underfunding precluded an active research...

Building a Profession

Physicists, chemists, and biologists were all considered professional scientists at the turn of the 20th century. Meteorologists and cli-matologists still labored on the fringes of the scientific community. Germany, Austria, and Scandinavia all had academic programs in meteorology and climatology with professors trained in those areas as the 20th century started, but the entire British Commonwealth did not have its first meteorological professorship until the appointment of Sir William Napier...

Unmasking Thunderstorms

Throughout the 1930s, meteorologists often referred to thunderstorms as heat thunderstorms because they thought they were usually triggered by intense surface heating. That heat would cause thunderstorms actually made sense. Thunderstorms were typically most severe on summer afternoons after the ground had been baked by the Sun all day. As the hot air rose, taking moisture with it, large cumulus clouds would begin to form. Within a few hours, the cumulus would continue to grow vertically,...

Taming a Tempest

Meteorologists may have been uncertain about the causes of hurricanes and the circumstances under which they strengthened, but that did not discourage people outside the discipline from making recommendations on ways to reduce the severity of hurricanes. Some people viewed the atomic bomb as the answer to controlling hurricanes. The power of the bomb, they thought, should be enough to offset the power of the hurricane. A nuclear weapon detonated within a nascent hurricane would sufficiently...

Figuring Out Hurricanes

Hurricanes, also known as typhoons in the western Pacific and tropical cyclones in the Indian Ocean, were giant, deadly, and unpredictable weather systems until the middle of the 20th century. In large part this was because they were difficult to study. Forming over equatorial waters out of sight of land, unless a ship happened to be unlucky enough to travel underneath one or the hurricane ran over an island in its path, they could be born, develop, and die without anyone ever knowing of their...

Weather Modification

In the immediate postwar years, political leaders, the general public, and many scientists embraced the idea that almost anything could be fixed with science and technology. World War II, the feeling went, had been won for the Allies by the skillful use of scientific development and technological achievement that had created the atomic bomb, radar, proximity fuses, rockets, and advanced aircraft designs. No longer content with damming streams for power and irrigation, tunneling through...

Radar A Military Tool for Meteorology

Since the 1930s, British scientists had been working on ground-based radar techniques. The very long wavelengths they employed combined with very broad beams made them difficult to use and provided very little directional accuracy. By 1940, the invention of the magnetron had provided a technique for creating very short wavelengths. Sir Henry Tizard (1885-1959), a prominent British physicist, showed his colleagues in the United States and Canada how the magnetron could enhance the usefulness of...

War Driven Research

The tactical and strategic needs of the military forces compelled meteorologists to postpone their personal research projects during the war. Academic meteorologists turned their attention to the most difficult problems first. Chemical warfare, which had been such a critical component of the war-fighting arsenal in World War I, was less important in World War II. The Chemical Warfare Service realized they needed very specific meteorological information if they were to use chemicals effectively....

Expanding the Observational Network

Besides drawing thousands into the meteorological discipline, World War II's requirements for operational data profoundly affected the growth of the atmospheric sciences. With aircraft operating in the Tropics of the Pacific theater, in the Caribbean, and in support of ships transiting the An upper-air observer prepares to launch a radiosonde during World War II. (NOAA Photo Library) Panama Canal, meteorologists needed an expanded network of surface and upper-air stations to provide accurate...

Forecasters by the Thousands

In the United States, military meteorology units had been disbanded at the end of World War I in conjunction with an overall reduction in military forces. Just a handful of meteorologists remained, primarily to provide aviation support services. The Weather Bureau's ranks of forecasters had been decimated by the Great Depression many senior meteorologists had been forced to retire and others had been laid off when there was no money to pay them. By 1940, as war in Europe started to look...

Guy Stewart Callendar Amateur Meteorologist

The British steam engineer Guy Stewart Callendar was the second son of the steam expert Hugh Longbourne Callendar (1863-1930) a fellow of the Royal Society of London. The younger Callendar followed in his father's footsteps, working as his assistant in conducting research on steam at high pressures and temperatures at the Royal College of Science. After his father's death in 1930, Callendar took over his father's classes and continued his own steam research experiments with funding provided by...

Carbon Dioxide and Global Warming

Research on climate change had languished since the early 20th century work of Svante Arrhenius and others who were trying to determine what factors might lead to atmospheric warming or cooling. Climatologists remained convinced that although climate had indeed been different in the past, it was not currently changing. Meteorologists were still focused on producing the next day's forecast. Research on the connection between atmospheric carbon dioxide (CO2) and atmospheric warming again fell to...

Little Radios and Big Balloons

Upper-air observations were critical to the successful application of Bergen School methods. Although tethered balloons and kites, free-floating balloons, and aircraft had been used to gather upper-air data since the early 20th century, they were all deficient in some way. Tethered balloons and kites could not fly as high in the atmosphere, and free-floating balloons carrying equipment packets had to be found before the data could be retrieved. (One set of instruments launched from Harvard's...

Norwegian Methods in the United States

Weather Bureau had proved extremely resistant to the Bergen School methods that swept European meteorology in the 1920s. The Swedish meteorologist Carl-Gustav Rossby, trained at the Bergen School and awarded a Scandinavian-American Association fellowship, had arrived in the United States in 1926 to work at the bureau. Rossby tried to convince bureau forecasters to use the frontal and air mass analysis techniques developed by the Bjerkneses he so irritated bureau leaders with his ideas...

Forecasting Lags Theory

The Bergen meteorologists had developed new and useful techniques for tying observational data to better forecasts, but not everyone adopted polar front theory and air mass analysis methods. The news about air mass analysis did spread quickly around the world, in no small part as a result of the efforts of Bergen School members who traveled to Russia, the United States, and throughout Europe to teach their techniques to every meteorologist who would listen. The American meteorologist and...

Balloons and Kites

Upper air observations depended on balloons and kites. The pioneering Montgolfier brothers of French ballooning, Jacques-Etienne (1745-99) and Joseph-Michel (1740-1810), had made their first manned flight on June 4, 1783, and manned balloons had been much improved by the early 20th century. Because of lack of oxygen, balloon-borne observers could not climb as high as the stratosphere and survive. Better unmanned balloons and kites capable of carrying meteorological equipment needed to be...

Climate Fears Drought and Desertification

As scientists mulled over whether the global climate was warming or cooling, one climatic impact was making headlines all over the world the devastating drought and accompanying expansion of deserts in the African Sahel. The Sahel, a region extending in an east-west band (4,000 miles wide by 1,000 miles 6,400 km by 1,600 km long) just south of the massive Sahara and home during this period to between 40 and 60 million people, depends on the summer monsoons for most of its yearly rainfall. If...

Layered Atmosphere

Since the invention of the barometer by the Italian scholar Evangelista Torricelli (1608-47) in 1644, early scientists had been trying to determine the thickness of the atmosphere. By the end of the 17 th century, scientists knew that air pressure decreased with height. It seemed logical that at some altitude there would be no pressure at all and they would have reached the top of the atmosphere. Of course, people could not actually get to the top because they would run out of air first. An...

Triggering Climate Change

The evidence was beginning to mount in the 1950s that climate was not a static geographic feature. Callendar's warnings from the late 1930s and early 1940s seemed to be more realistic with each passing year. The climate specialist Helmut E. Landsberg (1906-85) noted that there had been a noticeable warming trend on both sides of the northern Atlantic since the turn of the century. The Swedish glaciologist and climatologist Hans Ahlmann (1889-1974) pointed to the retreat of Iceland's Aobrekke...

The Rise of Atmospheric Modeling

The 1950s were years of fiscal retrenchment for the U.S. government, but the military services fighting the cold war had ample funds for basic research. The Office of Naval Research provided significant funding for numerical weather prediction, cloud physics, and a variety of weather control techniques. The National Science Foundation, established in 1950, would become the primary provider of basic research funds, while the military concentrated on applied research. The money that flowed into...

Numerical Dreams Numerical Reality

The idea of using mathematics to solve the weather forecasting problem was not a new one in 1946 Vilhelm Bjerknes had made a case for such an undertaking in the early 20th century and Lewis Fry Richardson of Great Britain had made an abortive attempt to do so during World War I. Both Bjerknes and Richardson realized that numerical weather prediction would not be practical until calculations could be made much more quickly than was possible with pencil, paper, and adding machines and or slide...

Decade by Decade

Set Editor William J. Cannon WEATHER AND CLIMATE Decade by Decade Copyright 2007 by Kristine C. Harper, Ph.D. All rights reserved. No part of this book may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage or retrieval systems, without permission in writing from the publisher. For information contact Facts On File, Inc. An imprint of Infobase Publishing 132 West 31st Street...

The Great Depression Aids Climatological Study

Weather Bureau had made a good start on compiling useful climatological data from stations throughout the United States through the end of World War I. Funding reductions in the immediate postwar years, however, led to the steady deterioration of climatological services after 1920. Lack of station reports was not the problem. Over 5,000 unpaid cooperative observers submitted reports of maximum and minimum temperatures, air pressure readings, and precipitation totals by mail to bureau...

Weather Prophets

Prior to the end of World War II, only government weather offices provided national forecasts. Before radio and television, forecasts were often posted in public places such as post offices and train stations, and occasionally printed in some big city newspapers. As a government service, weather forecasts were free. Free or not, most people were dissatisfied with them. Forecasts were most effective when they were tailored to a specific customer, for example, a farmer, construction firm, or road...

Snuffing Out Nascent Hurricanes

Cloud physicists had continued to uncover the mechanisms for cloud development and precipitation during the 1950s. Some of those advancements had been crucial to the further understanding of hurricane development and behavior. Others had been critical to the development of more sophisticated weather modification techniques. Progress in all of these areas merged in a joint Department of Commerce, Environmental Science Services Administration, and U.S. Navy effort called Project STORMFURY. Its...

Scientist of the Decade Carl Gustav Rossby

Born on December 28, 1898, in Stockholm, Sweden, the meteorologist Carl-Gustav Rossby was one of the most influential atmospheric scientists in the 20th century. After earning his filosofie kandidat that is, bachelor's degree at the University of Stockholm in 1918 with specializations in mathematics, mechanics, and astronomy, Rossby left Stockholm and moved to Norway to join the Bergen School. He worked with the Bjerkneses on the development of the polar front and air mass theories until 1921....

The Keeling Curve

The systematic measurement of atmospheric CO2 was one of the many data gathering efforts begun during the IGY and it has continued to the present time. The Weather Bureau's Harry Wexler 1911-62 , who led the atmospheric science efforts for the United States, obtained funding to install an infrared gas analyzer to make continuous readings of CO2 at the Mauna Loa Observatory on the Big Island of Hawaii. The observatory was chosen because of its location in the middle of the Pacific, far removed...

Shortcuts to Prediction

Wet Bulb Temperature Tephigram

Efforts to develop calculating aids to convert between different temperature scales, correct barometer readings, and compute atmospheric variables that could not be measured directly had started in the 19th century. By the beginning of the 20th century, calculating aids were being used to compute wind values from pressure data and rates of pressure change from temperature and pressure, and to make specialized calculations better solved with graphs. Stations reported temperatures in Celsius,...

The Cold War and Research Funding

In many ways, the 1950s was a period of financial retrenchment for much of science. European nations, still rebuilding after the war's devastation, had little in the way of spare funds for scientific research. Fiscal restraint was also a feature of the Eisenhower administration in the United States. While the Weather Bureau was trying to prepare for the introduction of numerical weather prediction techniques, which would require the acquisition of a computer and related peripheral equipment,...

The Bergen School

Bergen School Meteorology

In 1917, after three years of war, living conditions were deteriorating throughout Europe. Vilhelm Bjerknes, director of the Leipzig Geophysical Institute since 1913, had lost most of his assistants to the German military and many of them had died. He had imported several Norwegians to help, including Jacob, his 19-year-old son, but he was struggling to keep up with his research tying upper-air data and aeronautical activities with a more rational, scientific basis for meteorology. Bjerknes...

Scientist of the Decade Jacob Bjerknes

The Norwegian meteorologist Jacob Aall Bonnevie Bjerknes was born November 2, 1897, to modern meteorology's founder, Vilhelm Bjerknes, and Honoria Sophia Bonnevie in Stockholm, Sweden, where his father was a physics professor. Young Jacob was surrounded by an academic family his aunt Kristine Bonnevie 1872-1948 was a zoologist and the first female professor in Norway. Moving with his family to Christiania later Oslo , where his father had been offered a professorship, Jacob remained in Norway...

New Look at the Energy Budget

Energy Budget Weather

By the end of the 1950s, weather modification had evolved from being a matter of changes in local weather clearing fog, preventing frost on tender young fruit, reducing hail damage, generating rain to massive plans for climate control. One of the more grandiose schemes proposed by Russian scientists was to eliminate the Arctic ice cap in an attempt to warm up the northern and very cold regions of their country to improve their habitability. While the proposal itself may have been rather...

Scientist of the Decade Jule Gregory Charney

Jule Gregory Charney

The mathematician-turned-meteorologist Jule Charney was born in San Francisco, California, to Stella and Ely Charney both Russian migr s. Raised in Los Angeles, he was attracted to mathematics by the time he was in high school and had familiarized himself with the basics of differential and integral calculus before enrolling in the University of California, Los Angeles. Graduating from UCLA in 1938 with an A.B. with honors in both mathematics and physics, he turned his sights on graduate...

Scientist of the Decade Edward N Lorenz

Often referred to as the father of chaos theory, the meteorologist Edward N. Lorenz was born and raised in West Hartford, Connecticut. Fascinated by numbers at a young age, Lorenz experienced his first spark of scientific interest during an encounter with an astronomical atlas when he was seven years old. When a total eclipse of the Sun occurred the next summer, he was hooked. As are most people interested in astronomy, Lorenz was interested in the weather, since the condition of the night sky...

Cyclic Weather

Despite the Bergen School's influence on meteorological practice, some scholars persisted in their pursuit of elusive weather cycles. Weather cycles recurring patterns of temperature, rainfall, or pressure have been sought since ancient times, primarily as a way of predicting the weather months, if not years, in advance. The peak in studies of these periodicities occurred in the 1920s research rapidly dropped off in the 1930s as new calculation techniques cast doubt on cycles. Most work on...

Creating the Polar Front

Bjerknes Polarfront

With the 1919 summer forecasting season successfully concluded, the Norwegian government authorized Vilhelm Bjerknes and his assistants to issue storm warnings for the west coast during the fall and winter. The Bergen School members would be able to track and analyze the more intense fall and winter cyclones. They could also expand their research into cyclone structure. The decision by many European nations to take up to four observations daily in support of aviation also provided extra data...

Scientist of the Decade Tor Bergeron

The Swedish meteorologist Tor Bergeron was born in England but returned to Sweden with his family at a young age and completed his education there. After receiving his bachelor's degree in 1916, he joined the Swedish Weather Service as a meteorologist. Bergeron spent much of 1919 helping Vilhelm and Jacob Bjerknes establish their new forecasting program in Bergen. Jacob Bjerknes had introduced his now-famous cyclone model in 1918, but the complete model including the life cycle of the cyclone...

Climates Classified

A location's climate is generally described by the long-term average of temperature and precipitation. The word itself is derived from the Greek klima, which means slope. The well-traveled Greeks were aware that the countries lining the northern Mediterranean coast were warm and relatively moist compared to the dry desert regions east and south of the Mediterranean, and that countries in what we now call northern Europe were much colder. Trying to make sense out of these differences, they...

Statistical Meteorology

Numerical weather prediction was not the only forecasting technique to face opposition in the 1950s. Meteorologists who advocated the use of statistics as a prediction tool also confronted significant opposition from their synoptic meteorology colleagues. The synopticians those meteorologists who met the daily challenge of preparing weather forecasts viewed statistical methods with virtually the same disdain with which they had viewed the dynamic meteorology of Vilhelm Bjerknes some 50 years...

Keeping Planes in the

Commercial aviation expanded at a much faster rate than national weather services were equipped to support it during the 1920s. The rapid acceptance of air mass and frontal analysis throughout Europe attests to the desire to provide better flight forecasts for passenger and airmail flights. Upper-air data collection by means of pilot balloons, balloon-sondes, and aircraft assisted in this effort. Weather services in the United States remained at a disadvantage compared to those in European...

Why Frost

Supercooled Water Droplets

The German meteorologist Alfred Lothar Wegener 1880-1930 , best known for his theory of continental drift, had a wide variety of geophysical interests. Fascinated by Greenland, he made several expeditions to this frozen wasteland before his tragic death during a blizzard. Capitalizing on Greenland's ample opportunities to observe meteorological phenomena under freezing conditions, Wegener studied the formation of hoarfrost the interlocking crystals formed by direct deposition of water vapor...

Climate The Koppen Scheme

Wladimir Koppen's climate classification scheme, in various stages of development from its beginning in 1884, arrived at its ultimate form during the 1930s with the writing and publication of the five-volume Handbuch der Klimatologie Handbook of climatology . Edited by Koppen with his colleague Rudolph Geiger, these volumes presented the results of the latest climatological studies from around the world. They also presented the final version of Koppen's personal classification scheme. Climate...

The General Circulation of the Atmosphere

Wind patterns the physical manifestation of the general circulation of the atmosphere have been known since people starting sailing long distances across the oceans. Some, such as the Viking Erik the Red, found out about persistent westerly winds the hard way during failed attempts to sail from Iceland to Greenland. Others, such as Christopher Columbus, found that easterly winds would carry them across the Atlantic if they sailed down the west coast of Africa before trying to head west. By the...

Virtual Atmosphere and Real Weather

Jule Charney

Progress in numerical weather prediction continued throughout this decade. By 1952, Jule Charney and his Meteorology Project team had reached the point where it was time to talk about going operational. In all scientific research projects there is a time when the technique under development needs to leave the controlled world of the laboratory, where scientists have virtually unlimited time to analyze and perfect data, adjust their methodology, and consult other scientists. A new methodology...