History of Meteorology

1. History of Meteorology

2. Three General Historical Periods • Ancient Times: 600 B.C. to 1500 A.D. • 1500 A.D. to 1800 A.D. • 1800 A.D. to Modern Times

3. Meteorology • Word was invented by the Greeks over 200 years ago (Aristotle) meta = beyond eora = suspension Meteoros = high in the air Aristotle meant atmospheric elements such as rain, snow, hail, wind, thunder or lightning, and also earthquakes, comets and the Milky Way • Don’t confuse this with the astronomical terms for meteors which are extraterrestrial objects

4. Atmosphere • Also comes from the Greek Atmos = Vapor The atmosphere is a region of vapor

5. Ancient Period 600 B.C. to 1500 A.D. • Meteorology part of general science • Based on pseudo-scientific speculations • Scientific discoveries from all parts of the world: Babylonians, Sumerians, Chinese, Hindus, Egyptians, Greeks, Romans, and Arabs

6. Ancient Period • Babylonians – foundations of early mathematics and the four cardinal directions • Egyptians – defined weights and measures, invented ingenious water-clocks, and introduced the 365 day year • Chinese – invented the compass and made astronomical as well as meteorological observations

7. Ancient Period • Greeks – developed geometry, logic and philosophy – also performed meteorological observations and created physical theories Hippocrates: study of climate Aristotle: Meteorologica Theophrastus: meteorological treatise

8. Ancient Period • Romans – didn’t contribute much except in the field of organization, law, medicine, agriculture and the building of aqueducts Seneca – interested in meteorology • Middle Ages – stagnation in the arts and sciences – burned the library in Alexandria • Arabs – mathematics, optics and astronomy and the number system

9. A Water-Clock

10. 1500 – 1800 • Age of Genius and the Age of Reason • Copernicus – heliocentric theory of the universe • Foundations of modern meteorology laid in Europe with the invention of meteorological instruments and the introduction of meteorological observations

11. 1500 – 1800 • Galileo – invented the gas thermometer • Toricelli – invented the mercury barometer • Pascal and Descartes – showed pressure decreases with increasing altitude • Robert Hooke – swing-type anemometer for wind speed • Boyle – formulated the gas laws • Newton – the laws of mechanics • Euler – equations of fluid motion • Lavoisier – foundations of chemistry

12. 1500 – 1800 • Daniel Fahrenheit – temperature scale • George Hadley – influence of Earth’s rotation on winds in the tropics • Celsius – centigrade temperature scale • Ben Franklin – nature of lightning • Horace deSaussure – hair hygrometer for measuring humidity • Jacques Charles – relationship between temperature and the volume of air

13. 1800 to the present • Ekman - Mathematical models for atmospheric motion • 1821 – First crude weather maps • 1835 – George Coriolis – affect of Earth’s rotation on atmospheric motion • 1843 - Telegraph invented – transmission of weather observations • 1920 – concept of air masses • 1940’s – upper air balloon observations and discovery of the jet stream • Post World War II – surplus radars used for weather • 1950 – the first computer weather predictions by high speed computers • 1960 – First weather satellite Tiros I • 1990’s – Doppler Radar • Investigations of the vertical structure of the atmosphere • Sodars, lidars, radar, airplanes, satellites • Super computers

14. Ancient Experimenters • Eratosthenes – 330 BC – calculated the circumference of the Earth as 41, 660 km (today we know it to be 40,000 km)

15. Ancient Experimenters • Ptolemy (100 – 160) sexagesimal system of one hour equal to 60 minutes and each minute equal to 60 seconds • Fostered the advancement of science and established the great library in Alexandria. • Founded a university dedicated to Muses (Goddess of the Arts) called the Museum

16. Ancient Experimenters • Thales of Miletus – olive crop predictions based on weather observations (620 – 540 B.C.) • Genghis Khan defeated by Kublai Khan because a typhoon came along and destroyed his warships (the word Kamikaze which means “divine wind” came from this storm.

17. More Stories • Napoleon defeated at Waterloo because of bad weather that turned the battlefield into a swamp • Meteorology and the arts many connections songs and lyrics (Vivaldi’s Four Seasons) works of art literature – Romeo and Juliet story hinged on the influence of a hot day movies

18. Monitoring the Weather

19. Sources of Weather Information • The media: radio, television, newspapers, cell phones, iPods, the internet • Our senses: observation and feeling • Word of mouth • Educated Understanding • The “Weather Channel” – 24- hours a day • NOAA Weather Radio – 24-hours a day • Need a special radio

20. Weather Systems and Weather Maps • National and Regional weather maps • Satellite or radar images • Data on current and past weather conditions • Short term weather forecasts (24-48 hours) • Long term weather forecasts (up to 5 days or longer)

21. What’s included on a weather map? • Temperature • Dewpoint • Wind • Air pressure • Principle weather maker (pressure systems and fronts)

23. Pressure Systems • High Pressure called an anticyclone and represented by a blue H • Low Pressure called a cyclone and represented by a red L • Think of air pressure as the weight of a column of air that stretches from the Earth’s surface to the top of the atmosphere • The use of High and Low Pressure are relative terms

24. High Pressure • Usually means fair weather • Highs that originate in NW Canada bring cold, dry weather in the winter and cool, dry weather in the summer • Highs that develop in the south bring hot, dry weather in the summer and mild, dry weather in the winter

25. High Pressure • If viewed from above the winds blow in a clockwise and outward direction (in the Northern Hemisphere) • Calm conditions or light winds are typical over a broad area about the center of the high

26. Low Pressure • Lows produce cloudy, rainy or snowy weather (except in summer if they form over arid terrain) • Surface winds blow in a counterclockwise and inward spiral (in the Northern Hemisphere)

28. Pressure Centers • Move with the prevailing wind several kilometers above the surface (generally eastward in North America) • As they move they cause the weather to change • Highs follow lows and lows follow highs • High generally track towards the E and SE • Lows generally track towards and E and NE

29. Pressure Centers • Lows that track across the northern US usually produce less rain or snowfall than lows that track further south • Weather to the left side (west and north) of a storm’s track tends to be relatively cold • Weather to the right (east and south) of a storm’s track tends to be relatively warm