Atmospheric pressure is one of the most important climatic characteristics that affect weather conditions and people. It contributes to the formation of cyclones and anticyclones, provokes the development of cardiovascular diseases in humans. Evidence that air has weight dates back to the 17th century, and since then the process of studying its vibrations has been one of the central for weather forecasters.
What is the atmosphere
The word "atmosphere" is of Greek origin, literally it translates as "steam" and "ball". This is a gaseous shell around the planet, which rotates with it and forms a single whole cosmic body. It extends from the earth's crust, penetrating into the hydrosphere, and ends with the exosphere, gradually flowing into interplanetary space.
The planet's atmosphere is its most important element, providing the possibility of life on Earth. It contains the oxygen necessary for a person, weather indicators depend on it. The boundaries of the atmosphere are very arbitrary. It is generally accepted that they begin at a distance of about 1000 kilometers from the surface of the earth andthen, at a distance of another 300 kilometers, they smoothly pass into interplanetary space. According to the theories that NASA adheres to, this gaseous shell ends at an altitude of about 100 kilometers.
It arose as a result of volcanic eruptions and the evaporation of substances in space bodies that fell on the planet. Today, Earth's atmosphere is made up of nitrogen, oxygen, argon, and other gases.
History of the discovery of atmospheric pressure
Until the 17th century, mankind did not think about whether air has mass. There was also no concept of what atmospheric pressure was. However, when the Duke of Tuscany decided to equip the famous Florentine gardens with fountains, his project failed miserably. The height of the water column did not exceed 10 meters, which contradicted all ideas about the laws of nature at that time. This is where the story of the discovery of atmospheric pressure begins.
Galileo's student, the Italian physicist and mathematician Evangelista Torricelli, took up the study of this phenomenon. With the help of experiments on a heavier element, mercury, a few years later he was able to prove the presence of weight in air. He first created a vacuum in a laboratory and developed the first barometer. Torricelli imagined a glass tube filled with mercury, in which, under the influence of pressure, such an amount of substance remained that would equalize the pressure of the atmosphere. For mercury, the column height was 760 mm. For water - 10.3 meters, this is exactly thethe height to which the fountains in the gardens of Florence rose. It was he who discovered for mankind what atmospheric pressure is and how it affects human life. The airless space in the tube was named "Torricellian Void" after him.
Why and how atmospheric pressure is created
One of the key tools of meteorology is the study of the movement and movement of air masses. Thanks to this, you can get an idea of \u200b\u200bthe result of which atmospheric pressure is created. After it was proved that air has weight, it became clear that it, like any other body on the planet, is affected by the force of attraction. This is what causes pressure when the atmosphere is under the influence of gravity. Atmospheric pressure may fluctuate due to differences in air mass in different areas.
Where there is more air, it is higher. In rarefied space, a decrease in atmospheric pressure is observed. The reason for the change in air mass lies in its temperature. It is heated not from the rays of the Sun, but from the surface of the Earth. When heated, the air becomes lighter and rises, while the cooled air masses sink down, creating a constant, continuous movement of air masses. Each of these streams has a different atmospheric pressure, which provokes the appearance of winds on the surface of our planet.
Impact on the weather
Atmospheric pressure is one of the key terms in meteorology. Earth's weather is shaped bythe impact of cyclones and anticyclones, which are formed under the influence of pressure drops in the gaseous shell of the planet. Anticyclones are characterized by high rates (up to 800 mm Hg and above) and low speed, while cyclones are areas with lower rates and high speed. Tornadoes, hurricanes, tornadoes are also formed due to sudden changes in atmospheric pressure - inside the tornado it drops rapidly, reaching 560 mmHg.
The movement of air causes changes in weather conditions. Winds that arise between areas with different pressure levels overtake cyclones and anticyclones, as a result of which atmospheric pressure is created, which forms certain weather conditions. These movements are rarely systematic and very difficult to predict. In areas where high and low atmospheric pressure collide, climatic conditions change.
Standard indicators
The average under ideal conditions is 760 mmHg. The pressure level changes with altitude: in lowlands or areas below sea level, the pressure will be higher, at a height where the air is rarefied, on the contrary, its indicators decrease by 1 mmHg with each kilometer.
Reduced atmospheric pressure
It decreases with increasing altitude due to the distance from the surface of the Earth. In the first case, this process is explained by a decrease in the impact of gravitational forces.
Heating from the Earth, the gases that make up the air expand, their mass becomes lighter, and they rise to higher layers of the atmosphere. The movement occurs until the neighboring air masses are less dense, then the air spreads to the sides, and the pressure equalizes.
Traditional areas with lower atmospheric pressure are the tropics. In the equatorial territories, low pressure is always observed. However, zones with an increased and decreased index are unevenly distributed over the Earth: in the same geographical latitude, there may be areas with different levels.
High atmospheric pressure
The highest level on Earth is observed at the South and North Poles. This is because the air above the cold surface becomes cold and dense, its mass increases, therefore, it is more strongly attracted to the surface by gravity. It descends, and the space above it is filled with warmer air masses, as a result of which atmospheric pressure is created with an increased level.
Influence on a person
Normal indicators, characteristic of a person's area of residence, should not have any effect on his well-being. At the same time, atmospheric pressure and life on Earth are inextricably linked. Its change - increase or decrease - can provoke the development of cardiovascular diseases in people with high blood pressure. A person may experience pain in the region of the heart, seizurescauseless headache, decreased performance.
For people suffering from respiratory diseases, anticyclones can become dangerous, bringing high blood pressure. The air descends and becomes denser, the concentration of harmful substances increases.
During fluctuations in atmospheric pressure, immunity decreases in people, the level of leukocytes in the blood, so it is not recommended to load the body physically or intellectually on such days.
