Atmospheric pressure is one of the most important climatic characteristics that affect weather conditions and humans. It contributes to the formation of cyclones and anticyclones, provokes the development of cardiovascular diseases in humans. Evidence that air has weight was obtained back in the 17th century, since then the process of studying its vibrations is one of the central for weather forecasters.
What is the atmosphere
The word "atmosphere" is of Greek origin, literally it is translated as "steam" and "ball". This is the gas 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 atmosphere of the planet 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 and then at a distance of another 300 kilometers smoothly pass into interplanetary space. According to the theories held by NASA, this gas shell ends at an altitude of about 100 kilometers.
It arose as a result of volcanic eruptions and the evaporation of substances in cosmic bodies that fell on the planet. Today, the Earth’s atmosphere consists of nitrogen, oxygen, argon and other gases.
History of atmospheric pressure discovery
Until the 17th century, mankind did not think about whether air has mass. There was no idea 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 originates.
The study of this phenomenon was undertaken by a student of Galileo, the Italian physicist and mathematician Evangelista Torricelli. With the help of experiments on a heavier element, mercury, after several years he was able to prove the presence of weight in the air. He first created a vacuum in the laboratory and developed the first barometer. Torricelli imagined a glass tube filled with mercury, in which under the influence of pressure there remained such an amount of a substance that would equalize the pressure of the atmosphere. For mercury, the column height was 760 mm. For water - 10.3 meters, this is exactly the height to which the fountains rose in the gardens of Florence. 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 in his honor "Torricellian emptiness."
Why and why 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, one can get an idea of what creates atmospheric pressure. After it was proved that air has weight, it became clear that it, like any other body on the planet, is affected by gravity. This is what causes the occurrence of pressure when the atmosphere is under the influence of gravity. Atmospheric pressure can fluctuate due to differences in air mass in different areas.
Where there is more air, it is higher. In a 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 descend, creating a constant, continuous movement of air masses. Each of these flows has a different atmospheric pressure, which provokes the appearance of winds on the surface of our planet.
Weather effect
Atmospheric pressure is one of the key terms in meteorology. Weather on Earth is formed due to the effects of cyclones and anticyclones, which are formed under the influence of pressure drops in the gas shell of the planet. Anticyclones are characterized by high rates (up to 800 mm Hg and higher) 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 rapidly falls, reaching 560 mm Hg.
Air movement causes a change in weather conditions. Winds that arise between regions with different levels of pressure distill 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, a change in climatic conditions occurs.
Standard metrics
Under ideal conditions, the average level is 760 mm Hg. The pressure level changes with height: in lowlands or territories below sea level, the pressure will be higher, at a height where rarefied air, on the contrary, its performance decreases by 1 mmHg with every kilometer.
Low atmospheric pressure
It decreases with increasing altitude due to the distance from the Earth's surface. In the first case, this process is explained by a decrease in the influence of gravitational forces.
When heated 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 around and the pressure is equalized.
Tropics are considered traditional areas with lower atmospheric pressure. In the equatorial territories, there is always low pressure. However, zones with an increased and decreased indicator are distributed unevenly over the Earth: in one geographical latitude, areas with different levels may be present.
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 falls, and the space above it is filled with warmer air masses, as a result of which atmospheric pressure is created with an increased level.
Human impact
Normal indicators characteristic of the locality of a person 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 trigger the development of cardiovascular diseases in people with high blood pressure. A person may experience pain in the heart, bouts of causeless headache, decreased performance.
For people suffering from respiratory diseases, dangerous can be anticyclones that bring high blood pressure. The air drops and becomes denser, the concentration of harmful substances increases.
During fluctuations in atmospheric pressure, immunity and the level of leukocytes in the blood decrease in people, therefore it is not recommended to load the body physically or intellectually on such days.