Main topic information 1
Vocabulary/new concepts:
Meteorology is a study that describes and explains phenomena occurring in the Earth’s atmosphere.
Weather is the state of the atmosphere at a particular time in a particular place.
Climate refers to a long-term weather pattern for a place, or a region.
Weather elements include air temperature, air pressure, airflow, humidity, clouds, and precipitation.
When did the science of meteorology originate?
The history of meteorology dates back to the time of ancient civilizations. The movement of the stars, sun and moon, as well as precipitation, temperature and wind, have fascinated people. They observed and recorded these phenomena, and the ancient Greek philosopher Aristotle wrote the first known treatise on meteorology.
The transition from ancient to modern meteorology is linked to the dynamic development of scientific discoveries, and the development and refinement of new instruments such as barometers, thermometers and anemometers. Many of these are still in use today. What are they? Even before our era, a rain gauge in the form of an open cylindrical vessel with a flat bottom appeared in China. It is considered the first meteorological instrument. The thermometer became the most common instrument. Galileo Galilei constructed the first instrument to measure air temperature in 1597. In 1643, Evangelista Torricelli invented the mercury barometer, which measured atmospheric pressure. Thanks to this invention, much later Daniel Fahrenheit made the first mercury thermometer, on a scale he developed and named after him. It was the first to be standardised and applied worldwide and is still used in some countries for non-scientific purposes. Several different types of classical liquid thermometers have been used since. One of these is the Sykes extreme thermometer. It is a tube bent in the shape of the letter U, each arm having its own scale.
Another instrument used in meteorology is the hygrometer. It measures the relative humidity of the air. The first was invented by Leonardo Da Vinci in 1480, and the classic hair hygrometer was created by Horace de Saussure in 1783. It uses the fact that human hair changes its length depending on the change in humidity. Modern hygrometers are widely used in agriculture and animal husbandry, in industry and households.
Meteorology and weather forecasting
The first attempts at weather forecasting appeared in the 17th century. They were based on the dependence of atmospheric pressure change on altitude.
Meteorology studies the events that occur in the atmosphere – especially the weather, the causes of its changes, and weather forecasting. The main cause of weather changes is the Sun. The Sun heats the land, oceans and seas. Solar radiation causes water to evaporate, forming water vapour that mixes with the atmospheric air. The air is heated by the heated surface. Warmer air has a lower density than cold air. It therefore rises upwards. The cooler air descends towards the ground and so an airflow is created. The flowing air is the wind. The wind carries water vapour to other areas. Clouds are formed by the cooling and liquefaction of water vapour. Sometimes it snows or rains.
Weather is the state of the atmosphere at a particular time in a particular place. The typical weather conditions characteristic of a particular place, region, or territory over a long period is called climate. A different climate is characteristic of the Scandinavian countries in Europe, another for the countries around the Mediterranean Sea or the Sahara desert region. A meteorologist observes six main meteorological elements that affect the weather: air temperature, air pressure, airflow (wind), humidity, cloudiness and precipitation.
How are weather elements measured?
Specific instruments are used for this purpose:
Air pressure is measured with manometers. They can be mercury or box (aneroid).
A manometer with a recording device is a barograph. An interesting point is that instruments for measuring air pressure should not be placed in the meteorological cabin. Since atmospheric pressure is directly related to airflow, anemometers (they measure wind speed) or anemographs – instruments for measuring and recording wind speed and direction – are used.
The wind direction scale was introduced in 1805 by the English Admiral F. Beaufort.
The first official weather forecasts date from the 1st of January 1877. They were published by the Central Institute of Meteorology and Earth Magnetism in Vienna.
The device used to continuously record rainfall is called a rain gauge (ombrograph).
The heliograph (solar meter, solarimeter) is used to measure the duration of sunlight during the day. Its main part is a glass ball placed in an open spherical bowl divided into two halves. This ball acts as a magnifying glass that concentrates the rays in one place. Behind the magnifying glass is a cardboard strip/paper which is charred by the sun rays focused on it and leaves a trace. In this way, the duration of sunshine at a location is recorded. The heliograph is placed on a 1-metre-high brick plinth with the open side of the bowl facing south.
The limnograph allows continuous recording of the water level and the evaporimeter measures the rate of evaporation of water into the atmosphere.
The location of the instruments in the weather station is determined by the quantities they measure. The instruments for measuring temperature and humidity are placed in meteorological cabins. Instruments for measuring air pressure shall never be placed in the cabin.
