Meteorology on the earth is based on the regular observation of meteorological phenomena and on the study of laws which govern atmospheric gases, their states of matter and their movements.

Principal factors observed are atmospheric pressure, temperature, humidity, wind, precipitation and clouds. Movements in the atmosphere are due to the variation, according to latitude, in energy received by the earth that the earth yields by radiation.
On average, during the course of the year, the difference between the energy gained by the “Atmosphere Earth” and the energy lost through radiation is positive to the south of the 38th parallel and negative to the north. Beyond the 70th parallel, the outcome is negative the whole year, whilst in equatorial and tropical regions, it is always positive.

Air tends to move from regions where pressure is high (anticyclones) to those where pressure is weak (depressions). However, the rotation of the earth deflects any movements which take place on the surface of the earth.
In the northern hemisphere, the wind blows clockwise around anticyclones and anticlockwise around depressions; this is the opposite way round in the southern hemisphere.

The general circulation of the atmosphere depends on the average distribution of pressure on the globe, which is established as follows: a high pressure zone (anticyclones), not clearly indicated, in polar regions; a zone of relative low pressures (depressions) in temperate regions; a zone of subtropical high pressures; a zone of equatorial low pressures. Corresponding with this scheme is an average component of atmospheric currents: winds with E.-O. component in polar regions; winds with O.-E. component in temperate regions; winds with E.-O. component in inter-tropical regions.

The equatorial low pressure zone continues all year round, which explains the presence of trade winds.

The thermal exchanges between the hot regions and the cold regions of the globe take place thanks to gigantic whirlwinds which originate from temperate regions and meet with polar and tropical winds, thus creating a series of cold and warm fronts. The observation of meteorological phenomena by way of satellite has considerably advanced our knowledge of these phenomena and thus increases the length of time for which weather forecasts can be made.

The information which meteorology provides, which depends heavily on IT and teletransmission of data, is indispensable to any company whose activity depends on meteorological conditions (aviation, navy, farming, public services, hydroelectricity, etc.).

Stations for the general public, be these weather or temperature stations, are not as complex as the large scale equipment used by national meteorology services. But neither are they just gadgets. …
Such that we should take the opportunity here to warn users: the apparent simplicity of products sold on this site is just an illusion.

the reading of the manual for each station is imperative. Please also consult the sections of this knowledge database: transmission distances, interferences, radio-controlled time, do not overlook anything about the appliance you wish to or have purchased.

Owners of a Pro weather station or a large weather station will need patience: installing such an appliance needs time and perseverance. So, good luck and enjoy your weather!

For all history enthusiasts, some dates and events.

350 av. J.C.	Aristote was drawing up a treaty entitled Meteorologiae, dealing with « the study of the elements of air ». About a third of the work is devoted to atmospherical phenomena.
1500	Léonard de Vinci invents the weathercock
1639	Castelli invents the rain meter.
1641	Galilee invents the thermometer.
1643	Torricelli invents the mercury barometer. The instrument becomes more handy with the invention of the empty air capsule (aneroid barometer) by Vidi in 1874.
1650	Ferdinand II of Tuscany constructs the first hygroscope. (ancestor of the hygrometer by de Saussure in 1783)
1655	First ever meteorological readings, carried out in Florence. Continuous readings will not however be carried out until 1706 at Utrecht university.
1664	Invention of the anemometer by Hooke. It will be perfected in 1790 by Wattman.
1665	Huygens perfects the thermometer dreamt up by Galilee by fixing bearings to it, thanks to which measurement becomes possible.
1677	Measurement of rain becomes possible thanks to Townley’s rain meter.
1736	The Swede Celsius proposes the centennial scale, still in use (the one proposed by Réaumur in 1733 was quickly abandoned). The Anglo-Saxons still use the one drawn up by the German Fahrenheit in 1710.
1783	The first balloon explores the atmosphere up to an altitude of 3400m.
1854	On November 14th the French fleet is destroyed on the Black Sea by a violent storm. The astronomer Le Verrier, on the request of Marshall Vaillant, studies path of disruption across Europe and observes that it could have been predicted had a network of observatories existed.Le Verrier lays the foundations for French meteorology, based on a network of thirteen stations, and starts up a system for exchange of observations with European countries.
1863	The Paris observatory regularly broadcasts “weather bulletins”.
1878	The creation, in France, of the first national meteorological organisation. The same year, 32 countries assembled in Vienna, found the International Meteorological Organisation.
1886	The first meteorological messages come from North America; added to these the observations noted in the log books of ships.
1890	First atmospheric measurements at high altitude with the aid of kites.
1892	Gustave Hermite invents the weather balloon.
1898	Teisserenc de Bort and Assman launch weather balloons which don’t measure humidity.
1899	It is at the dawn of the 20th century that three weather balloons launched from Trappes (today in the Yvelines region of France) reach 13000m and help identify the stratosphere. Thirty odd so years later, the balloons are equipped with an antenna transmitting measurements (temperature, pressure, air humidity) depending on the ascension of the radio probe.
1927-1929	The meteorologists Bureau and Hydrac fix a radio antenna under a weather balloon for transmission of measurements in real time.
1937	Launching of the first ship equipped for meteorological readings: the "Carimaré", a French fighter ship. Ships of this kind still exist today. Since 1926, commercial ships also carry out atmopsherical measurements voluntarily.
1947	Creation of the Worldwide Meteorological Organisation (WMO), a specialised organisation of the UN, responsible for setting up a complete and rapid weather information exchange system between all member states.
1960	Putting into orbit of the first meteorological satellite (Tiros I, USA). Today, more than a hundred satellites have been launched. Meteosat is the European observation satellite.