History of MeteorologyHistory of Meteorology

Three General Historical Three General Historical PeriodsPeriods

Ancient Times: 600 B.C. to 1500 A.D.

1500 A.D. to 1800 A.D.1800 A.D. to Modern Times

MeteorologyMeteorology

Word was invented by the Greeks over 200 years ago (Aristotle)

meta = beyondeora = suspensionMeteoros = high in the airAristotle 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

AtmosphereAtmosphere

Also comes from the Greek

Atmos = Vapor

The atmosphere is a region of vapor

Ancient Period 600 B.C. to Ancient Period 600 B.C. to 1500 A.D.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

Ancient PeriodAncient 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

Ancient PeriodAncient Period

Greeks – developed geometry, logic and philosophy – also performed meteorological observations and created physical theories

Hippocrates: study of climate

Aristotle: Meteorologica

Theophrastus: meteorological treatise

Ancient PeriodAncient Period

Romans – didn’t contribute much except in the field of organization, law, medicine, agriculture and the building of aqueducts

Seneca – interested in meteorologyMiddle Ages – stagnation in the arts and

sciences – burned the library in AlexandriaArabs – mathematics, optics and astronomy

and the number system

A Water-ClockA Water-Clock

1500 – 1800 1500 – 1800

Age of Genius and the Age of ReasonCopernicus – heliocentric theory of the

universeFoundations of modern meteorology laid in

Europe with the invention of meteorological instruments and the introduction of meteorological observations

1500 – 18001500 – 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

1500 – 18001500 – 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

1800 to the present1800 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

Ancient ExperimentersAncient Experimenters

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

Ancient ExperimentersAncient 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

Ancient ExperimentersAncient 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.

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Napoleon defeated at Waterloo because of bad weather that turned the battlefield into a swamp

Meteorology and the artsmany connectionssongs and lyrics (Vivaldi’s Four

Seasons)works of artliterature – Romeo and Juliet story hinged on the influence of a hot daymovies

Monitoring the WeatherMonitoring the Weather

Sources of Weather Sources of Weather InformationInformation

The media: radio, television, newspapers, cell phones, iPods, the internet

Our senses: observation and feelingWord of mouthEducated UnderstandingThe “Weather Channel” – 24- hours a dayNOAA Weather Radio – 24-hours a day

– Need a special radio

Weather Systems and Weather Systems and Weather MapsWeather Maps

National and Regional weather mapsSatellite or radar imagesData on current and past weather conditionsShort term weather forecasts (24-48 hours)Long term weather forecasts (up to 5 days

or longer)

What’s included on a weather What’s included on a weather map?map?

TemperatureDewpointWindAir pressurePrinciple weather maker (pressure systems

and fronts)

Pressure SystemsPressure 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

High PressureHigh 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

High PressureHigh 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

Low PressureLow 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)

Pressure CentersPressure 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 highsHigh generally track towards the E and SELows generally track towards and E and NE

Pressure CentersPressure 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