Information about Millibar
The bar (symbol bar), decibar (symbol dbar) and the millibar (symbol mbar, also mb) are units of pressure. They are not SI units, but they are accepted for use with the SI. The bar is still widely used in descriptions of pressure because it is about the same as atmospheric pressure.
The bar and millibar were introduced by Sir Napier Shaw in 1909 and internationally adopted in 1929.
Americans are familiar with the millibar in US reports of hurricanes and other cyclonic storms, where lower central pressure generally means higher winds and a stronger storm.
In some countries, pressure is measured with reference to atmospheric pressure. This is gauge pressure and denoted by barg, often written with no spaces, spoken "bar gauge", and sometimes using symbols such as 'bar(g)'. For example, if someone says that their car tyres are pressurised to 2.3 bar they actually mean bar gauge: the pressure in the tyre is really 3.3 bar, but only 2.3 bar above atmospheric, which is the scale a tyre gauge would read. When absolute pressure is desired, it is sometimes denoted 'bara' or 'bar(a)' for "bar absolute". The alteration of units of measure for this purpose is now deprecated, with qualification of the physical property being preferred, e.g., "The gauge pressure is 2.3 bar; the absolute pressure is 3.3 bar".
In water, a measurement in decibars is approximately equal to the depth in meters; 1 decibar occurs at a depth of 1.019716 m.
Unicode has a character for "mb": (㏔), but exists only for compatibility with legacy Asian encodings; it should not be used in new texts.
Example reading: 1 Pa = 1 N/m2 = 10−5 bar = 10.19710−6 at = 9.869210−6 atm, etc.
Note: mmHg is an abbreviation for millimetres of mercury.
In physics, the dyne (symbol "dyn") is a unit of force specified in the centimeter-gram-second
..... Click the link for more information.
..... Click the link for more information.
In physics, the dyne (symbol "dyn") is a unit of force specified in the centimeter-gram-second
..... Click the link for more information.
Definition
The bar, decibar and millibar are defined as:- 1 bar = 100,000 pascals (Pa) = 1,000,000 dynes per square centimeter (baryes)
- 1 dbar = 0.1 bar = 10,000 Pa = 100,000 dyn/cm²
- 1 mbar = 0.001 bar = 100 Pa = 1,000 dyn/cm²
Origin
The word bar has its origin in the Greek word βάρος (baros), meaning weight. Its official symbol is "bar"; the earlier "b" is now deprecated, but still often seen especially as "mb" rather than the proper "mbar" for millibars.The bar and millibar were introduced by Sir Napier Shaw in 1909 and internationally adopted in 1929.
Discussion
Atmospheric air pressure is often given in millibars where "standard" sea level pressure is defined as 1013.25 mbar (hPa), equal to 1.01325 bar. Despite millibars not being an SI unit, they are still used locally in meteorology in some countries to describe atmospheric pressure. The SI unit is the pascal (Pa), with 1 mbar = 100 Pa = 1 hPa = 0.1 kPa. Meteorologists worldwide have long measured air pressure in millibars. After the introduction of SI units, many preferred to preserve the customary pressure figures. Therefore, some continue to use millibars under their own name, while others use hectopascals (which are equivalent to millibars) so they could stick to the same numeric scale. Similar pressures are given in kilopascals in practically all other fields, where the hecto prefix is hardly ever used. In particular, Canadian weather reports use kilopascals (which could also be called centibars).Americans are familiar with the millibar in US reports of hurricanes and other cyclonic storms, where lower central pressure generally means higher winds and a stronger storm.
In some countries, pressure is measured with reference to atmospheric pressure. This is gauge pressure and denoted by barg, often written with no spaces, spoken "bar gauge", and sometimes using symbols such as 'bar(g)'. For example, if someone says that their car tyres are pressurised to 2.3 bar they actually mean bar gauge: the pressure in the tyre is really 3.3 bar, but only 2.3 bar above atmospheric, which is the scale a tyre gauge would read. When absolute pressure is desired, it is sometimes denoted 'bara' or 'bar(a)' for "bar absolute". The alteration of units of measure for this purpose is now deprecated, with qualification of the physical property being preferred, e.g., "The gauge pressure is 2.3 bar; the absolute pressure is 3.3 bar".
In water, a measurement in decibars is approximately equal to the depth in meters; 1 decibar occurs at a depth of 1.019716 m.
Unicode has a character for "mb": (㏔), but exists only for compatibility with legacy Asian encodings; it should not be used in new texts.
pascal (Pa) |
bar (bar) |
technical atmosphere (at) |
atmosphere (atm) |
torr (mmHg) |
pound-force per square inch (psi) | |
|---|---|---|---|---|---|---|
| 1 Pa | ≡ 1 N/m2 | 10−5 | 1.019710−5 | 9.869210−6 | 7.500610−3 | 145.0410−6 |
| 1 bar | 100 000 | ≡ 106 dyn/cm2 | 1.0197 | 0.98692 | 750.06 | 14.504 |
| 1 at | 98 066.5 | 0.980665 | ≡ 1 kgf/cm2 | 0.96784 | 735.56 | 14.223 |
| 1 atm | 101 325 | 1.01325 | 1.0332 | ≡ 1 atm | 760 | 14.696 |
| 1 torr | 133.322 | 1.333210−3 | 1.359510−3 | 1.315810−3 | ≡ 1 mmHg | 19.33710−3 |
| 1 psi | 6 894.76 | 68.94810−3 | 70.30710−3 | 68.04610−3 | 51.715 | ≡ 1 lbf/in2 |
Note: mmHg is an abbreviation for millimetres of mercury.
External links
- Official SI website: Table 8. Non-SI units accepted for use with the SI
- Conversion factors from bar to various pressure units
See also
- Conversion of units
Pressure (symbol: p) is the force per unit area applied on a surface in a direction perpendicular to that surface.
Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.
..... Click the link for more information.
Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.
..... Click the link for more information.
Si, si, or SI may refer to (all SI unless otherwise stated):
In language:
..... Click the link for more information.
In language:
- One of two Italian words:
- sì (accented) for "yes"
- si
..... Click the link for more information.
Si, si, or SI may refer to (all SI unless otherwise stated):
In language:
..... Click the link for more information.
In language:
- One of two Italian words:
- sì (accented) for "yes"
- si
..... Click the link for more information.
- Dynes redirects here. For the president of the University of California system, see Robert C. Dynes.
In physics, the dyne (symbol "dyn") is a unit of force specified in the centimeter-gram-second
..... Click the link for more information.
1 centimetre =
SI units
010−3 m 0 mm
US customary / Imperial units
010−3 ft 0 in
A centimetre (American spelling: centimeter, symbol cmSI units
010−3 m 0 mm
US customary / Imperial units
010−3 ft 0 in
..... Click the link for more information.
barye (symbol: Ba) was in France a centimetre-gram-second (CGS) unit of pressure. It is equal to 1 dyne per square centimetre.
Other names: barad, barrie, bary, baryd, baryed, barie.
1 Ba = 0.1 Pa = 0.
..... Click the link for more information.
Other names: barad, barrie, bary, baryd, baryed, barie.
1 Ba = 0.1 Pa = 0.
..... Click the link for more information.
The pascal (symbol: Pa) is the SI derived unit of pressure or stress (also: Young's modulus and tensile strength). It is a measure of perpendicular force per unit area i.e. equivalent to one newton per square meter or one Joule per cubic meter.
..... Click the link for more information.
..... Click the link for more information.
The newton (symbol: N) is the SI derived unit of force, named after Sir Isaac Newton in recognition of his work on classical mechanics.
..... Click the link for more information.
Definition
A newton..... Click the link for more information.
Greek}}}
Writing system: Greek alphabet
Official status
Official language of: Greece
Cyprus
European Union
recognised as minority language in parts of:
European Union
Italy
Turkey
Regulated by:
..... Click the link for more information.
Writing system: Greek alphabet
Official status
Official language of: Greece
Cyprus
European Union
recognised as minority language in parts of:
European Union
Italy
Turkey
Regulated by:
..... Click the link for more information.
weight is a measurement of the gravitational force acting on an object. Near the surface of the Earth, the acceleration due to gravity is approximately constant; this means that an object's weight is roughly proportional to its mass.
..... Click the link for more information.
..... Click the link for more information.
Sir William Napier Shaw (4 March, 1854 - 23 March, 1945), British meteorologist. He introduced the air pressure unit millibar, as well as the tephigram, a diagram of temperature changes.
Shaw was born in Birmingham.
..... Click the link for more information.
Shaw was born in Birmingham.
..... Click the link for more information.
Atmospheric pressure is the pressure at any point in the Earth's atmosphere. In most circumstances atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point.
..... Click the link for more information.
..... Click the link for more information.
This article or section relies largely or entirely upon a .
Please help [ improve this article] by introducing appropriate of additional sources. ()
This article has been tagged since December 2006.
..... Click the link for more information.
Please help [ improve this article] by introducing appropriate of additional sources. ()
This article has been tagged since December 2006.
..... Click the link for more information.
The pascal (symbol: Pa) is the SI derived unit of pressure or stress (also: Young's modulus and tensile strength). It is a measure of perpendicular force per unit area i.e. equivalent to one newton per square meter or one Joule per cubic meter.
..... Click the link for more information.
..... Click the link for more information.
Si, si, or SI may refer to (all SI unless otherwise stated):
In language:
..... Click the link for more information.
In language:
- One of two Italian words:
- sì (accented) for "yes"
- si
..... Click the link for more information.
The pascal (symbol: Pa) is the SI derived unit of pressure or stress (also: Young's modulus and tensile strength). It is a measure of perpendicular force per unit area i.e. equivalent to one newton per square meter or one Joule per cubic meter.
..... Click the link for more information.
..... Click the link for more information.
tropical cyclone is a meteorological term for a storm system characterized by a low pressure system center and thunderstorms that produces strong wind and flooding rain. A tropical cyclone feeds on the heat released when moist air rises and the water vapor it contains condenses.
..... Click the link for more information.
..... Click the link for more information.
Unicode is an industry standard allowing computers to consistently represent and manipulate text expressed in any of the world's writing systems. Developed in tandem with the Universal Character Set standard and published in book form as The Unicode Standard
..... Click the link for more information.
..... Click the link for more information.
The pascal (symbol: Pa) is the SI derived unit of pressure or stress (also: Young's modulus and tensile strength). It is a measure of perpendicular force per unit area i.e. equivalent to one newton per square meter or one Joule per cubic meter.
..... Click the link for more information.
..... Click the link for more information.
A technical atmosphere (symbol: at) is a non-SI unit of pressure equal to 1 kilogram-force per square centimeter, i.e. 98.0665 kilopascals (kPa) or about 0.967 84 standard atmospheres.
..... Click the link for more information.
..... Click the link for more information.
Standard atmosphere is a pressure defined as 101 325 Pa and used as unit of pressure (symbol: atm). Standard atmosphere is a non-SI unit that is internationally recognized.
..... Click the link for more information.
..... Click the link for more information.
torr (symbol: Torr) is a non-SI unit of pressure defined as 1/760 of an atmosphere. It was named after Evangelista Torricelli, an Italian physicist and mathematician who discovered the principle of the barometer in 1644.
..... Click the link for more information.
..... Click the link for more information.
pound per square inch or, more accurately, pound-force per square inch (symbol: psi or lbf/sq in) is a unit of pressure or of stress based on avoirdupois units.
..... Click the link for more information.
..... Click the link for more information.
The newton (symbol: N) is the SI derived unit of force, named after Sir Isaac Newton in recognition of his work on classical mechanics.
..... Click the link for more information.
Definition
A newton..... Click the link for more information.
- Dynes redirects here. For the president of the University of California system, see Robert C. Dynes.
In physics, the dyne (symbol "dyn") is a unit of force specified in the centimeter-gram-second
..... Click the link for more information.
The unit kilogram-force (kgf, often just kg) or kilopond (kp) is defined as the force exerted by one kilogram of mass in standard Earth gravity.
..... Click the link for more information.
..... Click the link for more information.
Standard atmosphere is a pressure defined as 101 325 Pa and used as unit of pressure (symbol: atm). Standard atmosphere is a non-SI unit that is internationally recognized.
..... Click the link for more information.
..... Click the link for more information.
torr (symbol: Torr) is a non-SI unit of pressure defined as 1/760 of an atmosphere. It was named after Evangelista Torricelli, an Italian physicist and mathematician who discovered the principle of the barometer in 1644.
..... Click the link for more information.
..... Click the link for more information.
A pound or pound-force (abbreviations: lb, lbf, or lbf) is a unit of force. Pound is also the name of a unit of mass. One pound-force is approximately equal to the gravitational force exerted on a mass of one avoirdupois pound on the
..... Click the link for more information.
..... Click the link for more information.
This article is copied from an article on Wikipedia.org - the free encyclopedia created and edited by online user community. The text was not checked or edited by anyone on our staff. Although the vast majority of the wikipedia encyclopedia articles provide accurate and timely information please do not assume the accuracy of any particular article. This article is distributed under the terms of GNU Free Documentation License.
Herod_Archelaus
