scott m. rochette, ph.d. associate professor and chair department of the earth sciences the college...

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Did We Ever Know What We Were Doing? A Brief History of Weather Forecasting Scott M. Rochette, Ph.D. Associate Professor and Chair Department of the Earth Sciences The College at Brockport

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  • Slide 1

Scott M. Rochette, Ph.D. Associate Professor and Chair Department of the Earth Sciences The College at Brockport Slide 2 Outline Overview Earliest Observations Birth of a Science Refining Moments Important Forecasts The Advent of Technology Whats Next? Words to Live By (?) Slide 3 Why is Weather Forecasting So Difficult? Imagine a rotating spherical envelope 25 miles deep, made of a mixture of gases whose concentrations vary in space and time. Place it around an astronomical object nearly 8000 miles in diameter, with a bumpy surface. Tilt the whole system back and forth with respect to its source of heat and light, a nuclear reactor 93 million miles away. Freeze it at the poles of its axis of rotation and intensely heat it in the middle. Imagine that the gas mixture continually receives inputs from the surface below, generally calmly but occasionally from violent, highly localized injections. Subject the whole to tidal forces induced by the sun and a captive satellite. After watching the system, try to predict its state at one location on the sphere for a period of one to several days in advance. (adapted from Ryan 1982) Slide 4 Words to Live By 1 Death by burning shall be the punishment for the practice of weather forecasting. (17 th Century English law) Slide 5 Earliest Observations 1 Babylonia, circa 650 BCE: attempted prediction of short-term weather changes based on clouds and optical phenomena (halos, etc.) Slide 6 Earliest Observations 2 Greece, circa 340 BCE: Aristotle wrote Meteorologica, a four-volume philosophical treatise included theories regarding the formation of clouds, rain and hail, wind, thunder and lightning, and hurricanes also addressed astronomy, geography, and chemistry observations were remarkably acute, despite significant errors: did not believe wind was air in motion believed that the west winds are cold because they blow from the sunset the authority on weather theory for about 2000 years (until WHAM 13) Slide 7 Earliest Observations 3 China, circa 300 BCE: astronomers developed calendar divided the year into 24 festivals, each corresponding to a different type of weather India, circa 500 AD: Varahamihira wrote Brihat Samhita, Great Compilation 106 chapters theorized that rain comes from the sun Slide 8 Birth of a Science 1 Science implies reproducible results requires observations and measurements knowledge to this point based solely on observations development of weather instruments transformed meteorology into a natural science First weather instrument? 1450: first hygrometer Cardinal Nicholas de Cusa of Germany measured the weight change of a bag of wool Slide 9 First Weather Instruments 1 1590s: first thermometer Galileo Galilei of Italy glass spheres filled with alcohol (of slightly different densities) technically a thermoscope (no scale, only registers temperature differences) first scale would be added about 20 years later Slide 10 First Weather Instruments 2 1643: first barometer Evangelista Torricelli of Italy (student of Galileo) pump makers noted that they could get water to rise only about 10 meters filled a glass tube with mercury (density 14x higher than water) and inserted it into a dish found that the height of the mercury column rose and fell with changes in atmospheric pressure By allowing atmospheric measurements to be made, meteorology became a science Slide 11 Synoptic Weather Reports One could only do so much with weather information (observed or measured) for a single location The telegraph (invented in 1837) allowed weather information to be exchanged and collected Simultaneous (synoptic) weather observations became the basis for understanding and forecasting the weather Synoptic = to view together Slide 12 Galesburg, IL, February 1861 (Courtesy of NOAA National Weather Service) Slide 13 What did this do? Plotting synoptic observations on a map began to show repeating patterns and relationships storms were known to be associated with low pressure, but no relationship between wind and pressure was established William Redfield (1831) postulated that winds in hurricanes flow counterclockwise around a low-pressure center (based on a pattern of fallen trees) James Espy (1841) theorized that air flows toward low pressure and is forced to rise, leading to clouds and precipitation The establishment of weather maps proved both men correct Slide 14 Weather Maps First daily weather map series produced by Joseph Henry of the Smithsonian Institution Started in 1849 with a network of 150 volunteer observers 10 years later, the network quadrupled in size, including observers in Canada, Mexico, Latin America, and the Caribbean Precursor to the National Weather Service Slide 15 Murphys Winter Some of the first weather forecasts were produced based on theories of planetary or lunar influences (i.e., not based on meteorological observations) Patrick Murphy of Ireland was one of the more famous astrologer-meteorologists In 1837, he published The Weather Almanack (on Scientific Principles, showing the State of the Weather for every day of the year 1838) His forecast for 20 January 1838, Fair, probably lowest degree of winter temperature Slide 16 So How Did He Do? His forecast for London on 20 January 1838 was correct (temperature at sunrise was -4 F) As a result, his almanac was a best-seller, with a run of 45 editions (making him 3,000, a fortune then) However, an analysis of his 1838 performance showed him to be partially right on 188 days, but completely wrong on 197 days (54% of the year) He published almanacs for the next several years, which made him a decent living Poor speculating on grain prices cost him most of his fortune Slide 17 Vice-Admiral Robert FitzRoy Likely best known as the captain of the HMS Beagle (Darwin) Appointed in 1854 to the position of Meteorological Statist to the Board of Trade, in charge of collecting weather data from ships at sea A storm in 1859 that caused the loss of a clipper ship (450+ lost, 39 survivors) inspired him to create weather charts (similar to those made by Henry) These charts were used to make predictions of storms, which he called forecasting the weather Daily forecasts began to be published in The Times in 1860 Likely the first weather forecasts based on meteorological observations Slide 18 A Sad End for FitzRoy During that time, the standard for forecasting was set by the Royal Observatory Landmark accomplishments of Newton (1643-1727) and Leibniz (1646- 1716) ushered in an era of determinism If we can imagine a consciousness great enough to know the exact locations and velocities of all the objects in the universe at the present instant, as well as all forces,... It could calculate anything about the past or future from the laws of cause and effect. (P.-S. Laplace) Even though they were based on actual meteorological data, FitzRoys forecasts were not up to this standard The damage from astrologer-meteorologists caused distrust of government forecasts by the public and colleagues alike (unlike today, of course) Forced to abandon his efforts, FitzRoy committed suicide on 30 April 1865 Slide 19 Professor Cleveland Abbe Director of the Cincinnati Observatory Set up a volunteer observer network similar to that of Joseph Henry Selected observing equipment and trained observers Clerks would decode incoming data and plot them on maps Abbe gave the first official U.S. forecast on 19 February 1871 He demanded that his teams forecasts were precisely worded and covered four key elements: temperature, pressure, wind direction, and weather (clouds/ precipitation) 69% of their forecasts verified Slide 20 Abbes Accomplishments First Chief Scientist of newly formed national weather service under U. S. Army Signal Corps (1871-1915) Advocated for the establishment of time zones in the U.S. and North America (thereby allowing simultaneous weather observations) Founded Monthly Weather Review in 1872 (still in print!) Recognized the interdependence of forecasting, climatology, and physical theory (to the chagrin of meteorology students ever since) Slide 21 Early U.S. Weather Map, 1 January 1871 (courtesy of NOAA) Slide 22 Words to Live By 2 Probably northeast to southwest winds, varying to the southward and westward and eastward and points between, high and low barometer swapping around from place to place; probable areas of rain, snow, hail, and drought, succeeded or preceded by earthquakes, with thunder and lightning. (Mark Twain, 1876, on Professor Abbes likely weather forecast for New England) Slide 23 Words to Live By 3 He who shall predict weather will have no quite life any more, and runs great risk of becoming crazy from nervousness. (C. H. D. Buys Ballot, author of the Buys Ballot law) Slide 24 From Empiricism to Determinism Physical laws govern the motion of fluids (e.g., atmospheric gases) M. F. Spaaskii (1851), a Russian meteorologist, posed the idea that weather forecasting can be posed as a mathematical problem Prof. Abbe (1890) published Preparatory Studies of Deductive Methods in Storm and Weather Predictions, which furthered the idea that the laws of physics could be applied to weather prediction Henrik Mohn (Norway), Wladimir Kppen (Germany), and Max Margules (Ukraine) postulated that upper-level mechanisms generate energy for storms Slide 25 Words to Live By 4 Forecasting is immoral and damaging to the character of a meteorologist. (Max Margules) Slide 26 Professor Vilhelm Bjerknes The pioneer of modern weather forecasting His 1904 paper provided the basis for numerical weather prediction some 50 years before the first computer model The future state of the atmosphere can be determined given: the initial conditions of the atmosphere appropriate governing equations Established the Bergen School of Meteorology in 1917 Son Jacob would also contribute significantly Slide 27 Lewis Fry Richardson The first person to attempt numerical weather prediction (1922, without a computer) A Quaker and a pacifist: he served in WWI as an ambulance driver developed his theories about NWP during this time Attempted a forecast of pressure change (from 4 am to 10 am 20 May 1910, near Munich) six-hour forecast took six weeks predicted pressure change: 145 mb! actual pressure change: < 1 mb greatest range of observed pressure ~100 mb Slide 28 Richardsons Forecast Factory Aside from the time problem, Richardson used the full equations should have neglected small-scale processes think of a jar filled with rocks of different sizes He figured about 64,000 people (with hand calculators) would be needed to keep up with the worlds weather envisioned a giant theatre to house them the light would shine on areas that needed to slow down or speed up Gave up weather and focused on peaceful pursuits Lived to see the first successful NWP attempt Slide 29 Professor Jacob Bjerknes Member of the Bergen School Published a paper in 1922 (at 25!) establishing the Norwegian cyclone model: extratropical cyclone life cycle cold, warm, occluded fronts still used today Founded the UCLA Department of Meteorology in 1940 one of five meteorology departments formed that year MIT, Cal Tech, NYU, University of Chicago Slide 30 Further Advances 1930s: Radiosondes make upper- air data available in near-real time 1930s-WWII: Radar first developed as method for tracking ships and aircraft WWII: Weather found as noise in radar imagery Slide 31 Some Important Forecasts June 1944: Operation Overlord Captain John Stagg, RAF Eisenhower wanted five-day forecasts (!) Weather requirements: no fog/low clouds