What is the unit of atmospheric pressure?

The international unit of air pressure is Pascal, abbreviated as Pa, and the symbol is PA. Air pressure is the atmospheric pressure acting on the unit area, that is, it is numerically equal to the gravity of the vertical air column extending upward to the upper limit of the atmosphere. The famous experiment in the hemisphere of Fort Madre proved its existence.

In meteorology, people usually use kilopascals (kPa) or hectopascals (hpa) as units. Other commonly used units are bar (bar, 1 bar =100,000 pa) and centimeter mercury (or centimeter mercury). Air pressure varies not only with height, but also with temperature. The change of air pressure is closely related to the change of weather.

Air pressure is the atmospheric pressure acting on the unit area, which is equal to the weight of the vertical air column extending upward to the upper limit of the atmosphere. Air pressure is related to altitude, temperature and other conditions. It generally decreases with the increase of height.

In the horizontal direction, the difference of atmospheric pressure leads to air flow. A unit of air pressure, usually the height of a mercury column. For example, a standard atmospheric pressure is equal to the weight of a mercury column with a height of 760mm, which is equivalent to bearing an atmospheric pressure of1.0336kg in an area of one square centimeter.

Internationally, "hectopascals" are used as the air pressure unit. After conversion: a standard atmospheric pressure = 10 13 hectopascals (millibars). The annual average pressure in Shenzhen is 1009.8 hectopascals.

Extended data:

A, commonly used units:

Standard atmospheric pressure. A unit of air pressure, usually the height of a mercury column. For example, a standard atmospheric pressure is equal to the weight of a mercury column with a height of 760mm, which is equivalent to bearing an atmospheric pressure of1.0336kg in an area of one square centimeter.

Because the weight and length units used in different countries are different, and the pressure units are not uniform, it is not convenient to compare and analyze the global pressure. Therefore, "hectopascals" are used as the air pressure unit in the world.

After conversion: a standard atmospheric pressure =1.013 *105pa (hectopascals).

1 mm Hg height =4/3 hectopascals (hectopascals)

1 standard atmospheric pressure = 760mmhg height.

Second, the unit conversion:

1 MPa = 1000 kpa = 100000 Pascal

1 bar = 0. 1 MPa

1 atmospheric pressure (standard atmospheric pressure) = 0.10/3mpa =1.013bar = 760mmhg =10.33mmhg.

1kgf/cm2 (engineering kilogram force) = 0.981bar = 0.0981MPa.

1 psi = 0.0703 1 kgf/cm2 =0.06893 bar = 6.893 kpa.

1 MPa = 145 psi

Psi(lb/in2) pound/square inch is commonly used for product parameters in English-speaking countries such as Europe and America.

Usually, the word "kg" in the industry refers to "bar"

References:

Baidu encyclopedia-air pressure