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05 March 2026
This event began 03/05/2025 and repeats every year forever
Electronic Numerical Integrator and Compiler (ENIAC) is the first computer + first machine to make a weather model to predict the weather, here is how 03/05/1950
https://aalbc.com/tc/blogs/entry/482-electronic-numerical-integrator-and-compiler-eniac-is-the-first-computer-first-machine-to-make-a-weather-model-to-predict-the-weather-here-is-how/
IF YOU DONT WANT TO USE THE LINK ABOVE
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The first successful numerical prediction was performed using the ENIAC digital computer in 1950 by a team led by American meteorologist Jule Charney. The team include Philip Thompson, Larry Gates, and Norwegian meteorologist Ragnar Fjørtoft, applied mathematician John von Neumann, and computer programmer Klara Dan von Neumann, M. H. Frankel, Jerome Namias, John C. Freeman Jr., Francis Reichelderfer, George Platzman, and Joseph Smagorinsky.[THE ENIAC FORECASTS A Re-creation ][The Unheralded Contributions of Klara Dan von Neumann][A Vast Machine] They used a simplified form of atmospheric dynamics based on solving the barotropic vorticity equation over a single layer of the atmosphere, by computing the geopotential height of the atmosphere's 500 millibars (15 inHg) pressure surface.[Numerical Integration of the Barotropic Vorticity Equation] This simplification greatly reduced demands on computer time and memory, so the computations could be performed on the relatively primitive computers of the day.[https://archive.org/details/stormwatcherstur00cox_df1/page/208/mode/2up] When news of the first weather forecast by ENIAC was received by Richardson in 1950, he remarked that the results were an "enormous scientific advance."[The origins of computer weather prediction and climate modeling] The first calculations for a 24‑hour forecast took ENIAC nearly 24 hours to produce,[The origins of computer weather prediction and climate modeling] but Charney's group noted that most of that time was spent in "manual operations", and expressed hope that forecasts of the weather before it occurs would soon be realized.[Numerical Integration of the Barotropic Vorticity Equation]
ARTICLES
THE ENIAC FORECASTS A Re-creation
https://maths.ucd.ie/~plynch/Publications/ENIAC-BAMS-08.pdf
The Unheralded Contributions of Klara Dan von Neumann
https://www.smithsonianmag.com/science-nature/meet-computer-scientist-you-should-thank-your-phone-weather-app-180963716/
Despite having no formal mathematical training, she was a key figure in creating the computer that would later launch modern weather prediction
Sarah Witman
June 16, 2017
Editor's note, May 20, 2021: We’ve updated this piece to more accurately reflect Klara Dan von Neumann’s contributions to the experiment that resulted in the first numerical weather predictions in 1950. The piece originally misstated that Klara was in charge of hand-punching and managing the 100,000 punchcards that served as the ENIAC’s read/write memory, when in fact she wasn’t present for this part of the experiment. The story has been re-edited to reflect this information.
A weather app is a nifty tool that predicts your meteorological future, leveraging the strength of satellites, supercomputers, and other modern devices to tell you when to pack an umbrella. Today, computerized weather prediction—like moving pictures or seatbelts in cars—is so commonplace that most smartphone users don’t give it a second thought. But in the early 20th century, the idea that you might be able to forecast the weather days or even weeks ahead was a tantalizing prospect. One of the most important breakthroughs in weather forecasting took place in the spring of 1950, during an experiment at the Aberdeen Proving Ground, a U.S. Army facility in Maryland. For 33 days and nights, a team of scientists and computer technicians worked tirelessly to achieve something that meteorologists had been working toward for decades: predict the weather mathematically. This was well before the age of pocket-sized, or even desktop, computers. The team—led by scientists Jule Charney, Ragnar Fjørtoft, John Freeman, George Platzman, and Joseph Smagorinsky—was using one of the world’s first computers: a finicky, 150-foot machine called ENIAC that had been developed during the recent World War. Platzman would later describe a complicated, 16-step process they repeated over and over: six steps for the ENIAC to run their calculations, and 10 steps to input instructions and record output on punch-cards. Minor errors forced them to redo hours—sometimes days—of work. In one tense moment, a computer operator’s thumb got caught in the machinery, temporarily halting operations. But at the end of the month, the team had produced six groundbreaking weather forecasts (well, technically, "hindcasts," since they used data from past storms to demonstrate the method). An article in the New York Times hailed the project as a way to “lift the veil from previously undisclosed mysteries connected with the science of weather forecasting.” The benefits to agriculture, shipping, air travel and other industries “were obvious,” weather experts told the Times, offering the potential to save crops, money, and lives. An internal Weather Bureau memo commended “these men” for proving that computer-based forecasting, the cornerstone of modern weather prediction, was possible. This was mostly true—except, it wasn’t just men. Numerous women played critical scientific roles in the experiment, for which they earned little to no credit at the time.
Two computer operators, Ruth Lichterman (left) and Marlyn Wescoff (right), wire the right side of the ENIAC with a new program in the pre-von Neumann era. US Army, via Historic Computers Images of the ARL Technical Library
Like the ENIAC’s first programmers—Jean Bartik, Betty Holberton, Kathleen Antonelli, Marlyn Meltzer, Ruth Teitelbaum, and Frances Spence—the computer operators for the 1950 weather experiment were all women. While this highly skilled work would surely have earned them a co-authorship today, their names—Norma Gilbarg, Ellen-Kristine Eliassen, and Margaret Smagorinsky, who was the first female statistician hired by the Weather Bureau and the wife of meteorologist Joseph Smagorinsky—are absent from the journal article detailing the experiment’s results. Before most of the scientists arrived at Aberdeen, these women spent hundreds of hours calculating the equations that the ENIAC would need to compute in the full experiment. “The system that they were going to use on the big computer, we were doing manually,” Margaret recalled in an interview with science historian George Dyson before she died in 2011. “It was a very tedious job. The three of us worked in a very small room, and we worked hard.” But perhaps the biggest single contribution, aside from the scientists leading the experiment, came from a woman named Klara Dan von Neumann. Klara, known affectionately as Klari, was born into a wealthy Jewish family in Budapest in 1911. After World War I, in which Hungary allied with Austria to become one of the great European powers of the war, Klara attended an English boarding school and became a national figure skating champion. When she was a teenager, during Budapest’s roaring '20s, her father and grandfather threw parties and invited the top artists and thinkers of the day—including women. Klara married young, divorced and remarried before the age of 25. In 1937, a Hungarian mathematician, John von Neumann, began to court her. Von Neumann was also married at the time, but his divorce was in progress (his first wife, Mariette, had fallen in love with the acclaimed physicist J.B. Horner Kuper, both of whom would become two of the first employees of Long Island’s Brookhaven National Laboratory). Within a year, John and Klara were married. John had a professorship at Princeton University, and, as the Nazis gained strength in Europe, Klara followed him to the U.S. Despite only having a high school education in algebra and trigonometry, she shared her new husband’s interest in numbers, and was able to secure a wartime job with Princeton’s Office of Population Research investigating population trends. By this time, John had become one of the most famous scientists in the world as a member of the Manhattan Project, the now-notorious U.S. government research project dedicated to building the first atomic bomb. With his strong Hungarian accent and array of eccentricities—he once played a joke on Albert Einstein by offering him a ride to the train station and then intentionally sending him off on the wrong train—he would later become the inspiration for Stanley Kubrick’s Dr. Strangelove. While Klara stayed behind, working full-time at Princeton, John moved out to Los Alamos, New Mexico, running the thousands of calculations needed to build the first of these weapons of mass destruction. His work came to fatal fruition in 1945, when the U.S. dropped two atomic bombs on Japan, killing as many as 250,000 people.
A chart of the series of operations required to create the first weather forecasts, chronicled later by scientist George Platzman. AMS Bulletin, ©American Meteorological Society. Used with permission.
After the war, John decided to turn his mathematical brilliance toward more peaceful applications. He thought he might be able to use the ENIAC—a powerful new computer that cut its teeth running calculations for an early hydrogen bomb prototype—could be applied to help improve weather forecasting. As John began to pursue this idea, getting in touch with top meteorologists in the U.S. and Norway, Klara came to visit him in Los Alamos. Living apart during the Manhattan Project had been hard on their marriage, and Klara had suffered a miscarriage back in New Jersey, but the trip rekindled sparks between them. By this time, Klara had become quite mathematically adept through her work at Princeton, and she and John began to collaborate on the ENIAC. “I became Johnny’s experimental rabbit,” she told Dyson years afterward. “I learned how to translate algebraic equations into numerical forms, which in turn then have to be put into machine language in the order in which the machine has to calculate it, either in sequence or going round and round, until it has finished with one part of the problem, and then go on some definite which-a-way, whatever seems to be right for it to do next.”<br> <br> The work was challenging, especially compared to modern computer programming with its luxuries like built-in memory and operating systems. Yet, Klara described to Dyson, she found coding to be a “very amusing and rather intricate jigsaw puzzle.”
Women computer scientists holding different parts of an early computer. From left to right: Patsy Simmers, holding ENIAC board; Gail Taylor, holding EDVAC board; Milly Beck, holding ORDVAC board; Norma Stec, holding BRLESC-I board. US Army Photo, via Historic Computers Images of the ARL Technical Library
In the acknowledgements of the 1950 paper detailing the first numerical weather predictions, the authors thank Klara for her “instruction in the technique of coding for the ENIAC and for checking the final code.” But what is undoubtedly her most impactful contribution to the experiment took place several years prior: helping to transform the ENIAC from a rigidly hard-wired machine into one of the first stored-program computers, more akin to today’s personal computers. Both Klara and John felt this was a necessary improvement for future applications like the weather experiment, as it would allow them to store a vast repertoire of commands in the computer’s memory. In 1947, Klara and Nick Metropolis—a Greek-American mathematician and computer scientist, and leader of the Los Alamos computing group—collaborated on a plan to implement this new mode on the ENIAC, and in 1948 they traveled to Aberdeen to reconfigure the machine. After training five other people to program and run the ENIAC (two married couples and a bachelor: Foster and Cerda Evans, Harris and Rosalie Mayer, and Marshall Rosenbluth), they worked for 32 days straight to install the new control system, check it, and get the modified machine up and running. By the end of the trip, Klara had reportedly lost 15 pounds, and it took her several weeks and numerous doctor’s visits to recover from the experience. But she still managed to write a full report on the conversion and use of the ENIAC as a stored-program computer. “The method is clearly a 100% success,” John wrote at the time. By the time Charney and his team of scientists arrived at Aberdeen in early 1950, Platzman would recall years later, the “ENIAC had been operating in the new stored-program mode for over a year, a fact that greatly simplified our work.” In a letter to his wife written during this first week, Platzman gushed: “The machine is a miracle.” The ENIAC was still rudimentary: It could only produce 400 multiplications per second, so slow that it produced rhythmic chugging noises. But after working around the clock for over a month, the team had six precious gems to show for their efforts: two 12-hour and four 24-hour retrospective forecasts. Not long after the weather experiment concluded, tragedy befell the von Neumann family. John von Neumann was confined to a wheelchair in 1956, and succumbed to cancer a year later, (likely due, at least in part, to his proximity to radiation during the Manhattan Project). Klara wrote the preface to his posthumous book, The Computer and the Brain, which she presented to Yale College in 1957. In it, she briefly described her late husband’s contributions to the field of meteorology, writing that his “numerical calculations seemed to be helpful in opening entirely new vistas,” but gave no mention of her own role. Klara’s work with computers seems to have tapered off even before John’s death. Whatever her reasoning may have been for this, it was in line with the prevailing trend at the time. Janet Abbate recounts in her 2012 book Recoding Gender how, as the public perception of computers and their value to society evolved throughout the 1950s and ’60s, the number of women hired for those roles shrank rapidly. Abbate writes that, while the women who made up most of the workforce in the early days of coding “would have scoffed at the notion that programming would ever be considered a masculine occupation,” that’s exactly what happened within a matter of years. Today, less than 8 percent of software developers worldwide identify as women, nonbinary, or gender nonconforming. While female representation in the fields of science, technology, engineering, and math has increased as a whole since the 1970s, according to the U.S. Census Bureau, the number of women working in computing roles has actually declined over the past few decades. But without their early contributions to the field, we might have missed out on the breakthrough that led to modern weather prediction, or any number of scientific advancements. So the next time you scroll through your weather app before deciding whether to don a raincoat, think of Klara and the other women who helped make it possible.
A Vast Machine
https://web.archive.org/web/20120127215929/http://mitpress.mit.edu/catalog/item/default.asp?ttype=2&tid=12080
Computer Models, Climate Data, and the Politics of Global Warming
Paul N. Edwards
Table of Contents and Sample Chapters
Computer Models, Climate Data, and the Politics of Global Warming
Paul N. Edwards
Acknowledgments
Download Chapter as PDF Sample Chapter - Download PDF (71 KB) ix
Introduction
Download Chapter as PDF Sample Chapter - Download PDF (121 KB) xiii
1 Thinking Globally
Download Chapter as PDF Sample Chapter - Download PDF (1.82 MB) 1
2 Global Space, Universal Time
Seeing the Planetary Atmosphere 27
3 Standards and Networks
International Meteorology and the Réseau Mondial 49
4 Climatology and Climate Change before World War II 61
5 Friction 83
6 Numerical Weather Prediction 111
7 The Infinite Forecast 139
8 Making Global Data 187
9 The First WWW 229
10 Making Data Global 251
11 Data Wars 287
12 Reanalysis
The Do-Over 323
13 Parametrics and the Limits of Knowledge 337
14 Simulation Models and Atmospheric Politics, 1960–1992 357
15 Signal and Noise
Consensus, Controversy, and Climate Change 397
Conclusion 431
Notes 441
Index
Download Chapter as PDF Sample Chapter - Download PDF (106 KB) 509
Global warming skeptics often fall back on the argument that the scientific case for global warming is all model predictions, nothing but simulation; they warn us that we need to wait for real data, "sound science." In A Vast Machine Paul Edwards has news for these skeptics: without models, there are no data. Today, no collection of signals or observations—even from satellites, which can "see" the whole planet with a single instrument—becomes global in time and space without passing through a series of data models. Everything we know about the world's climate we know through models. Edwards offers an engaging and innovative history of how scientists learned to understand the atmosphere—to measure it, trace its past, and model its future.
Edwards argues that all our knowledge about climate change comes from three kinds of computer models: simulation models of weather and climate; reanalysis models, which recreate climate history from historical weather data; and data models, used to combine and adjust measurements from many different sources. Meteorology creates knowledge through an infrastructure (weather stations and other data platforms) that covers the whole world, making global data. This infrastructure generates information so vast in quantity and so diverse in quality and form that it can be understood only by computer analysis—making data global. Edwards describes the science behind the scientific consensus on climate change, arguing that over the years data and models have converged to create a stable, reliable, and trustworthy basis for establishing the reality of global warming.
About the Author
Paul N. Edwards is Professor in the School of Information and the Department of History at the University of Michigan. He is the author of The Closed World: Computers and the Politics of Discourse in Cold War America (1996) and a coeditor (with Clark Miller) of Changing the Atmosphere: Expert Knowledge and Environmental Governance (2001), both published by the MIT Press.
Numerical Integration of the Barotropic Vorticity Equation
https://a.tellusjournals.se/articles/10.3402/tellusa.v2i4.8607
Original Research Papers
Authors
J. G. Charney
R. Fjörtoft
J. von Neumann
Abstract
A method is given for the numerical solution of the barotropic vorticity equation over a limited area of the earth’s surface. The lack of a natural boundary calls for an investigation of the appropriate boundary conditions. These are determined by a heuristic argument and are shown to be sufficient in a special case. Approximate conditions necessary to insure the mathematical stability of the difference equation are derived. The results of a series of four 24-hour forecasts computed from actual data at the 500 mb level are presented, together with an interpretation and analysis. An attempt is made to determine the causes of the forecast errors. These are ascribed partly to the use of too large a space increment and partly to the effects of baroclinicity. The rôle of the latter is investigated in some detail by means of a simple baroclinic model.
The origins of computer weather prediction and climate modeling
https://web.archive.org/web/20100708191309/http://www.rsmas.miami.edu/personal/miskandarani/Courses/MPO662/Lynch,Peter/OriginsCompWF.JCP227.pdf
from
Peter Lynch
IN AMENDMENT
Reading the Manual for ENIAC, the World’s First Electronic Computer
https://thenewstack.io/reading-the-manual-for-eniac-the-worlds-first-electronic-computer/
ENIAC (Electronic Numerical Integrator and Compiler) was the world's very first fully electronic general-purpose computer. Smithsonian magazine once called it "the room-size government computer that began the digital era." And last week the I Programmer site shared a link to an original operating manual for ENIAC, originally published 75 years ago this month.
Jun 16th, 2019 6:00am by David Cassel
I don't know my love, I know a business exist. Michael jackson was a huge client, but he wasn't alone, many black people in the entertainment industry have skin lightened , and the newspapers don't tend to go into it.
Feature image: US Army photo of the ENIAC.
Sometimes you have to take a long look back to realize just how much things have changed. And if you looked around our modern-day, cloud-enhanced web this month, you’d find several sites sharing memories about the launch of the ENIAC computer in 1946 — and of all those unstoppable mid-century engineers who tirelessly made it work.
ENIAC (Electronic Numerical Integrator and Compiler) was the world’s very first fully electronic general-purpose computer. Smithsonian magazine once called it “the room-size government computer that began the digital era.” And last week the I Programmer site shared a link to an original operating manual for ENIAC, originally published 75 years ago this month.
It’s dated June 1st, 1946 — it was published by the school of engineering at the University of Pennsylvania in Philadelphia — and the manual’s page at Archive.org show it’s been viewed just 2,309 times. (“There are no reviews yet,” reads the boilerplate on the site. “Be the first one to write a review.”)
The archive identifies it as part of “the bitsavers.org collection” — a project started by a software curator at the Computer History Museum, with over 98,500 files and more than 4.7 million text pages. So what can we glean about the ENIAC’s moment in history from the manual which documents its operation? It seems like the machine was temperamental. For example, it warns that the DC power should never be turned on without first turning the operation switch to “continuous.” “Failure to follow this rule causes certain DC fuses to blow, -240 and -415 in particular.” But the consequences are even worse if you opened the DC fuse cabinet when the D.C. power was turned on. “This not only exposes a person to voltage differences of around 1,500 volts but the person may be burned by flying pieces of molten fuse wire” (if one of the fuse cases suddenly blew). In fact, the ENIAC was actually designed with a door switch shunt that prevented it from operating if one of its panel doors was open, “since removing the doors exposes dangerous voltage.” But this feature could be bypassed by holding the door switch shunt in its closed position. In a video shared by the Computer History Archives Project, chief engineer J. Presper Eckert Jr remembers that it was rare to go more than a day or two without at least one tube blowing out. And in addition to potential shocks, dust was another potential hazard. “Dust particles may cause transient relay failures,” the manual warns, “so avoid stirring up dust in the ENIAC room.” “Also, if any relay case is removed, always replace in exactly the same position in order not to disturb dust inside the case.” The ENIAC used an IBM card reader, but that had its own issues too. At one point the manual actually recommends against having the same number in every column of a punchcard, since “this weakens a card increasing the probability of ‘jamming’ in the feeding mechanism of the IBM machines.” Essential Instructions<br> Despite these limitations, ENIAC was a remarkable piece of technology. The manual includes intricate drawings and detailed diagrams of its racks, trays, cables, and wiring. But most important are the front panel drawings, which “show in some detail the switches, sockets, etc. for each panel of each unit.”
“They contain the essential instructions for setting up a problem on the ENIAC.”
ENIAC’s panels were equipped with neon lights corresponding to things like the “denominator flip-flop” and the “divide flip-flop.” The manual includes footnotes that carefully explain under what circumstances each light will be lit. “The square root of zero is perhaps the easiest test to repeat on the divider-square rooter…” It’s not until page 28 that it explains that turning on the start switch “starts the initiating sequences for the ENIAC, turning on the DC power supplies, the heaters of the various panels, and the fans…” And it also turns on a little amber light. “When this sequence has been completed, showing that the ENIAC is ready to operate, the green light goes on…” There were gates for a “constant transmitter” (which transmits to an “accumulator”), and its circuitry included “program pulse input terminals” — for add pulses and subtract pulses. And the machine also included two “significant figures switches.” “When 10 or more significant figures are desired, the left-hand switch is set to 10 and the right-hand switch set so that the sum of the two switch readings equals the number of significant figures desired.” There are tantalizing glimpses of how it all works together. The manual recommends a complicated test to make sure all the hardware is working properly. It involves a card with the value P 11111 11111, which gets input into the machine’s “accumulator” 18 times. The mathematical result — 19,999,999,998 — apparently exceeds the range of the accumulator, so the expected result is actually M 99999 99998. Then a card with the value P 00000 00001 is transmitted to the accumulators exactly twice — which instead of twenty billion (20,000,000,000) should give the value P 00000 00000. “Note that this test assumes that the significant figure switch is set to ’10’…” In Smithsonian magazine, technology writer Steven Levy remembers living in Philadelphia in the 1970s and renting an apartment from a man named J. Presper Eckert Jr. “It was only when I became a technology writer some years later that I realized that my landlord had invented the computer.”
video not available https://www.youtube.com/watch?v=G8R6li54R20
In the early 1940s, Eckert had been a graduate student in the school of engineering who became the ENIAC’s chief engineer. A professor had proposed electronic calculations for munitions trajectories to help the American military during World War II. Levy calls it “a breathtaking enterprise. The original cost estimate of $150,000 would rise to $400,000. Weighing in at 30 tons, the U-shaped construct filled a 1,500-square-foot room. Its 40 cabinets, each of them nine feet high, were packed with 18,000 vacuum tubes, 10,000 capacitors, 6,000 switches and 1,500 relays… Two 20-horsepower blowers exhaled cool air so that ENIAC wouldn’t melt down.” By the time they’d finished building it — World War II was over. But there was still work to do. The Atomic Heritage Foundation site reports that ENIAC was used to help perform the engineering calculations for the world’s first hydrogen bomb (along with two other more-recently developed computers). “It took sixty straight days of processing, all through the summer of 1951.” Levy cites an Army press release describing ENIAC as a “mathematical robot” that “frees scientific thought from the drudgery of lengthy calculating work.” A recent documentary called The Computers reminds modern-day viewers that the ENIAC’s original programmers were all women — Kay McNulty, Betty Jennings, Betty Snyder, Marlyn Wescoff, Fran Bilas and Ruth Lichterman.
There’s now also a site called the ENIAC Programmers Project that shares a brief overview of the documentary with more information. During World War II, the U.S. military had put together a team of nearly 100 women, trained in mathematics, who were calculating complex ballistic-trajectory equations. Six of them were selected to program the ENIAC. Back in 1996, the IEEE Annals of the History of Computing ran a profile of “The Women of ENIAC,” interviewing 10 of the women who’d worked with the computer during its 10-year run. The poster for the documentary describes them as “six women lost from history who created technologies that changed our world.” The ENIAC was eventually left behind by ever-faster and ever-cheaper computers. “By the time it was decommissioned in 1955 it had been used for research on the design of wind tunnels, random number generators, and weather prediction,” remembers an ENIAC web page at Oak Ridge National Laboratory. And even though ENIAC was decommissioned in 1955, 50 years later it was reassembled for a humble ceremony in Philadelphia, Levy remembers. “Vice President Al Gore threw a switch and the remaining pieces clattered out the answer to an addition problem.” According to Levy, the ENIAC’s chief engineer later groused “How would you like to have most of your life’s work end up on a square centimeter of silicon?” But Levy sees another way to look at it. “[T]he question could easily have been put another way: How would you like to have invented the machine that changed the course of civilization?” Yet legacies aside, it also seems like it was a real thrill just to have been a part of the work itself. “I’ve never seen been in as exciting an environment,” remembers Jean Jennings Bartik in the film. “We knew we were pushing back frontiers.” And more than 60 years later, she also still remembered that the ENIAC computer “was a son-of-a-bitch to program.”
The Women of ENIAC
https://web.archive.org/web/20160304052225/http://www.eg.bucknell.edu/~csci203/2012-fall/hw/hw06/assets/womenOfENIAC.pdf
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05 March 2026
This event began 03/05/2026 and repeats every year forever
https://www.deviantart.com/hddeviant/journal/WATN-Wall-E-1286566667
supporting story
https://aalbc.com/tc/events/event/667-silver-inspirations/
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