Meteorology

History of meteorology

Early achievements in meteorology

• 350 BCE

The term meteorology comes from Aristotle's Meteorology.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Although the term meteorology is used today to describe a subdiscipline of the atmospheric sciences, Aristotle's work is more general. The work touches upon much of what is known as the earth sciences. In his own words:

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

...all the affections we may call common to air and water, and the kinds and parts of the earth and the affections of its parts.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

One of the most impressive achievements in Meteorology is his description of what is now known as the hydrologic cycle:

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Now the sun, moving as it does, sets up processes of change and becoming and decay, and by its agency the finest and sweetest water is every day carried up and is dissolved into vapour and rises to the upper region, where it is condensed again by the cold and so returns to the earth.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

• 1607

Galileo Galilei constructs a thermoscope. Not only did this device measure temperature, but it represented a paradigm shift. Up to this point, heat and cold were believed to be qualities of Aristotle's elements (fire, water, air, and earth). Note: There is some controversy about who actually built this first thermoscope. There is some evidence for this device being independently built at several different times. This is the era of the first recorded meteorological observations. As there was no standard measurement, they were of little use until the work of Daniel Gabriel Fahrenheit and Anders Celsius in the 18th century.

Related Topics:
Galileo Galilei - Thermoscope - Paradigm shift - Daniel Gabriel Fahrenheit - Anders Celsius

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

• 1643

Evangelista Torricelli, a contemporary and one-time assistant of Galileo, creates the first man-made sustained vacuum in 1643, and in the process creates the first barometer. Changes in height of mercury in this Toricelli Tube lead to his discovery that atmospheric pressure changes over time.

Related Topics:
Evangelista Torricelli - Vacuum - 1643 - Barometer

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

• 1648

Blaise Pascal discovers that atmospheric pressure decreases with height, and deduces that there is a vacuum above the atmosphere.

Related Topics:
Blaise Pascal - Atmospheric pressure

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

• 1667

Robert Hooke builds an anemometer to measure windspeed.

Related Topics:
Robert Hooke - Anemometer

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

• 1686

Edmund Halley maps the trade winds, deduces that atmospheric changes are driven by solar heat, and confirms the discoveries of Pascal about atmospheric pressure.

Related Topics:
Edmund Halley - Pascal

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

• 1735

George Hadley is the first to take the rotation of the Earth into account to explain the behavior of the trade winds. Although the mechanism Hadley described was incorrect, predicting trade winds half as strong as the actual winds, the circulating cells that Hadley described later become known as Hadley cells.

Related Topics:
George Hadley - Trade winds - Hadley cell

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

• 1743-1784

Benjamin Franklin observes that weather systems in North America move from west to east, demonstrates that lightning is electricity, publishes the first scientific chart of the Gulf Stream, links a volcanic eruption to weather, and speculates about the effect of deforestation on climate.

Related Topics:
Benjamin Franklin - North America - Lightning - Electricity - Gulf Stream - Volcanic eruption - Deforestation - Climate

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

• 1780

Horace de Saussure constructs a hair hygrometer to measure humidity.

Related Topics:
Horace de Saussure - Hygrometer

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

• 1802-1803

Luke Howard writes On the Modification of Clouds in which he assigns cloud types Latin names.

Related Topics:
Luke Howard - Cloud types - Latin

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Synoptic-scale weather observations were still hindered by the difficulty of establishing certain weather characteristics such as clouds or wind. These were solved when Luke Howard and Francis Beaufort introduced their systems for classifying clouds (1802) and wind speeds (1806), respectively. The real turning point however was the invention of the telegraph in 1843 that allowed exchange of weather information with unprecedented speed.

Related Topics:
Synoptic - Cloud - Wind - Luke Howard - Francis Beaufort - 1802 - 1806 - Telegraph - 1843

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

The Coriolis Effect

Understanding the kinematics of how exactly the rotation of the Earth affects airflow was partial at first. Late in the 19th century the full extent of the large scale interaction of pressure gradient force and deflecting force that in the end causes air masses to move along isobars was understood. Early in the 20th century this deflecting force was named the Coriolis Effect after Gaspard-Gustave Coriolis, who had published in 1835 on the energy yield of machines with rotating parts, such as waterwheels. In 1856, William Ferrel proposed the existence of a circulation cell in the mid-latitudes with air being deflected by the coriolis force to create the prevailing westerly winds.

Related Topics:
Force - Isobar - Gaspard-Gustave Coriolis - 1856 - William Ferrel - Cell

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Numerical weather prediction

Early in the 20th century, advances in the understanding of atmospheric dynamics led to the foundation of modern numerical weather prediction. In 1922, Lewis Fry Richardson published `Weather prediction by numerical process` which described how small terms in the fluid dynamics equations governing atmospheric flow could be neglected to allow numerical solutions to be found. However, the sheer number of calculations required was too large to be completed before the advent of computers.

Related Topics:
20th century - Atmospheric dynamics - Numerical weather prediction - 1922 - Lewis Fry Richardson

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

At this time in Norway a group of meteorologists led by Vilhelm Bjerknes developed the model that explains the generation, intensification and ultimate decay (the life cycle) of midlatitude cyclones, introducing the idea of fronts, that is, sharply defined boundaries between air masses. The group included Carl-Gustaf Rossby (who was the first to explain the large scale atmospheric flow in terms of fluid dynamics), Tor Bergeron (who first determined the mechanism by which rain forms) and Jacob Bjerknes.

Related Topics:
Vilhelm Bjerknes - Life cycle - Midlatitude - Cyclones - Front - Air masses - Carl-Gustaf Rossby - Fluid dynamics - Tor Bergeron - Jacob Bjerknes

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Starting in the 1950s, numerical experiments with computers became feasible. The first weather forecasts derived this way used barotropic (that means, single-vertical-level) models, and could successfully predict the large-scale movement of midlatitude Rossby waves, that is, the pattern of atmospheric lows and highs.

Related Topics:
1950 - Numerical - Weather forecast - Barotropic - Rossby wave - Atmospheric lows - Highs

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

In the 1960s, the chaotic nature of the atmosphere was first understood by Edward Lorenz, founding the field of chaos theory. These advances have led to the current use of ensemble forecasting in most major forecasting centers, to take into account uncertainty arising due to the chaotic nature of the atmosphere.

Related Topics:
1960s - Chaotic - Edward Lorenz - Ensemble forecasting

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Satellite observation

In 1960, the launch of TIROS-1, the first successful weather satellite marked the beginning of the age where weather information is available globally. Weather satellites along with more general-purpose Earth-observing satellites circling the earth at various altitudes have become an indispensable tool for studying a wide range of phenomena from forest fires to El Niño.

Related Topics:
1960 - TIROS-1 - Weather satellite - El Niño

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

In recent years, climate models have been developed that feature a resolution comparable to older weather prediction models. These climate models are used to investigate long-term climate shifts, such as what effects might be caused by human emission of greenhouse gases.

Related Topics:
Climate model - Climate - Greenhouse gas

~ ~ ~ ~ ~ ~ ~ ~ ~ ~