This is my entry to 
You can find the article's (in Greek)and picture's sources here:
http://www.meteoclub.gr/themata/egkyklopaideia/3173-meteorology-history-sections-definition
''METEOROLOGY''
DEFINITION AND HISTORICAL RETURN:
It is the science that deals with the various phenomena that occur in the atmosphere and explores how they are created and evolved in time.
The term meteorology derives from the ancient Greek word 'ΜΕΤΕΩΡΟΝ', which characterized every object suspended in the atmosphere, such as clouds, rain drops, hail etc. For the ancient Greek philosophers, meteorology was not a separate science, but it was closely linked with Astronomy. From the first observations related to Meteorology are those made by Thalis in 640 BC. , who gave the succession of the four seasons of the year to the continus position change of the Sun in the sky, and separated them (as is still today) from the spring and autumn equinoxes, as well as from the winter and summer solstice.
Meteorology also includes 'Hippocrates' observations in the 5th century BC. , who studied with great care the meteorological conditions that must prevail in the populated areas, in order to protect the health of the inhabitants. This set the foundations of the Meteorology branch, which is known as Biometeorology.
But the first systematic study of meteorological phenomena comes from Aristotle, about 340 BC. , and is known with the name ''Meteorological''.
In this work he presents observations and interpretations of many meteorological phenomena such as the formation of rain and hail, the winds, the phenomenon of the halo, etc. It is true that some of Aristotle's views abstained from reality, and in some cases, they refuted other more correct interpretations of phenomena that had previously been expressed before by other Ancient Greek philosophers. For example, Anaxagoras had expressed the view that hail is created in the storm mainly in the summer and in areas that are heavily heated, because the heated air is subjected to supreme forces so that the cloud is forced to rise to low temperatures, freezes the drops of water it contains. On the contrary, Aristotle rejected this theory and suggested that the hailstorm is caused by downward movements, often involving storm clouds. Nevertheless, in many other cases of atmospheric phenomena, such as rain formation, the phenomenon of halo, etc. , the interpretations given by Aristotle were admirably documented.
Aristotle's views were still fully accepted until the time of the Renaissance. The first step in the evolution of Meteorology during this abstention was the discovery of two instruments, the barometer, and the thermometer. Although the initial concept of both of these inventions is due to Galileo (G. Galilei), the barometer was first constructed by Torricelli (Torricelli) in 1643,
the thermometer, in the form in which it is known today by Celsius (A. Celcius) in 1742.
At the same time, all fundamental natural laws that are directly or indirectly involved in the natural processes taking place in the atmosphere have gradually begun to take place, so that the last ones can be explored.
However, the evolution of Meteorology, even after the 18th century. continued with a steady but relatively slow pace. At the same time in the 18th and 19th centuries. , many attempts have been made to provide a theoretical explanation of some basic characteristics of atmospheric behavior, such as the general circulation of the atmosphere by J. Handley in 1735, and W. Ferrel in 1856, the barometric low movement by W. Redfield and W.Reid (1840), the role of latent heat in the creation of the storms by J. Espy, at about the same time, etc. .
An important milestone in the evolution of Meteorology was the mapping of the first weather maps in 1820 by G. Brandes. From these maps, for the first time, the existence of barometric systems on the surface was evident in practice. From 1855 onwards, the first Meteorological services in the world began to be established. The French Meteorological Service was founded first, based in the Observatory of Paris and director U. Leverrier, followed immediately by the establishment of US meteorological services. , England, and the Netherlands.
The creation of meteorological services in the rest of western and central European countries continued in the coming decades. A series of international conferences having as goal the corporation between countries' Meteorological services, in Vienna in 1873, in Russia in 1874, in Munich in 1891 and in Paris in 1896, where all the necessary specifications were established, in the preparation of weather maps. In 1878 the International Meteorological Organization was created , which since 1950 has been renamed to << World Meteorological Organization >> (W.M.O.).
SECTORS OF METEOROLOGY
- Physical Meteorology. Studies the physical structure and chemical composition of the atmosphere, the spread of electromagnetic radiation (solar radiation, radio waves, etc.) as well as the acoustic waves in the atmosphere, the natural processes involved in the formation of clouds and sky in general and, finally, a wide range of topics related to certain physical and chemical processes that take place in the atmosphere.
- Dynamic Meteorology. Studies the development and timing of atmospheric movements and their behavior through mathematical analysis using natural laws governing fluid movement.
- Synoptical Meteorology. Deals with the description, analysis and prognosis, based on empirical methods, of large (concise) scale atmospheric movements. In recent decades, with the evolution of physical atmospheric simulation models and the constant improvement of their predictive potential, Synoptical Meteorology has gradually begun to be subtracted from the numerical weather forecast.
- Agricultural Meteorology. Examines the effect of weather conditions on the growth of plants mainly on agricultural crops, special forecasts are issued for growers to take preventive protective measures
- Biometeorology. Studies the impact of weather conditions on humans
- Aeronautical Meteorology (Naval and Air). Studies the conditions affecting aeronautical transport
- Radio Meteorology. Studies the effect of various natural atmospheric processes on wireless telecommunications
