Atmospheric pressure

barometric pressureair pressurepressurecentral pressuresurface pressureminimum central pressurepressuresbarostaticsea level pressuremean sea level pressure
Atmospheric pressure, sometimes also called barometric pressure (after the sensor), is the pressure within the atmosphere of Earth.wikipedia
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Barometer

barometricaneroid barometerbarometers
Atmospheric pressure, sometimes also called barometric pressure (after the sensor), is the pressure within the atmosphere of Earth.
A barometer is a scientific instrument that is used to measure air pressure in a certain environment.

Atmosphere of Earth

airEarth's atmosphereatmosphere
Atmospheric pressure, sometimes also called barometric pressure (after the sensor), is the pressure within the atmosphere of Earth.
The atmosphere of Earth protects life on Earth by creating pressure allowing for liquid water to exist on the Earth's surface, absorbing ultraviolet solar radiation, warming the surface through heat retention (greenhouse effect), and reducing temperature extremes between day and night (the diurnal temperature variation).

Pascal (unit)

hPaMPakPa
Pressure measures force per unit area, with SI units of Pascals (1 pascal = 1 newton per square metre, 1N/m 2 ).
Meteorological forecasts typically report atmospheric pressure in hectopascals per the recommendation of the World Meteorological Organization.

Pressure

water pressurenegative pressurefluid pressure
Atmospheric pressure, sometimes also called barometric pressure (after the sensor), is the pressure within the atmosphere of Earth.
For gases, pressure is sometimes measured not as an absolute pressure, but relative to atmospheric pressure; such measurements are called gauge pressure.

Pounds per square inch

psilb f /in 2 psig
The standard atmosphere (symbol: atm) is a unit of pressure defined as 101325 Pa, equivalent to 760mm Hg, 29.9212inchesHg, or 14.696psi.

QNH

local barometric pressure at mean sea levelpressure
In aviation, weather reports (METAR), QNH is transmitted around the world in millibars or hectopascals (1 hectopascal = 1 millibar), except in the United States, Canada, and Colombia where it is reported in inches of mercury (to two decimal places).
indicating the atmospheric pressure adjusted to mean sea level.

Inch of mercury

inHginches of mercuryinches
The standard atmosphere (symbol: atm) is a unit of pressure defined as 101325 Pa, equivalent to 760mm Hg, 29.9212inchesHg, or 14.696psi. In aviation, weather reports (METAR), QNH is transmitted around the world in millibars or hectopascals (1 hectopascal = 1 millibar), except in the United States, Canada, and Colombia where it is reported in inches of mercury (to two decimal places).
It is used for barometric pressure in weather reports, refrigeration and aviation in the United States.

Siberian High

Siberian anticycloneSiberian windsSiberia
In the US weather code remarks, three digits are all that are transmitted; decimal points and the one or two most significant digits are omitted: 1013.2 mbar is transmitted as 132; 1000.0 mbar is transmitted as 000; 998.7mbar is transmitted as 987; etc. The highest sea-level pressure on Earth occurs in Siberia, where the Siberian High often attains a sea-level pressure above 1050 mbar, with record highs close to 1085 mbar.
The atmospheric pressure is often above 1040 mbar.

METAR

SPECIaviation flight categoryaviation
In aviation, weather reports (METAR), QNH is transmitted around the world in millibars or hectopascals (1 hectopascal = 1 millibar), except in the United States, Canada, and Colombia where it is reported in inches of mercury (to two decimal places).
A typical METAR contains data for the temperature, dew point, wind direction and speed, precipitation, cloud cover and heights, visibility, and barometric pressure.

Sea level

mean sea levelMSLAMSL
On average, a column of air with a cross-sectional area of 1 square centimetre (cm 2 ), measured from mean (average) sea level to the top of Earth's atmosphere, has a mass of about 1.03 kilogram and exerts a force or "weight" of about 10.1 newtons, resulting in a pressure of 10.1 N/cm 2 or 101kN/m 2 (101 kilopascals, kPa).
The global MSL is a type of vertical datum – a standardised geodetic datum – that is used, for example, as a chart datum in cartography and marine navigation, or, in aviation, as the standard sea level at which atmospheric pressure is measured to calibrate altitude and, consequently, aircraft flight levels.

Atmosphere (unit)

atmatmospheresatmosphere
The standard atmosphere (symbol: atm) is a unit of pressure defined as 101325 Pa, equivalent to 760mm Hg, 29.9212inchesHg, or 14.696psi.

Climate

climaticclimatesaverage annual temperature
Atmospheric pressure varies widely on Earth, and these changes are important in studying weather and climate.
Some of the meteorological variables that are commonly measured are temperature, humidity, atmospheric pressure, wind, and precipitation.

Pressure system

complex systemshigh-pressure systemhigh-pressure systems
See pressure system for the effects of air pressure variations on weather.
A pressure system is a relative peak or lull in the sea level pressure distribution.

Metre

metermmetres
Pressure measures force per unit area, with SI units of Pascals (1 pascal = 1 newton per square metre, 1N/m 2 ).

Tornado

tornadoestornadicwedge tornado
The lowest measurable sea-level pressure is found at the centers of tropical cyclones and tornadoes, with a record low of 870 mbar.
In addition to winds, tornadoes also exhibit changes in atmospheric variables such as temperature, moisture, and pressure.

International System of Units

SISI unitsSI unit
Pressure measures force per unit area, with SI units of Pascals (1 pascal = 1 newton per square metre, 1N/m 2 ).
In the late 19th and early 20th centuries, a number of non-coherent units of measure based on the gram/kilogram, centimetre/metre, and second, such as the Pferdestärke (metric horsepower) for power, the darcy for permeability and "millimetres of mercury" for barometric and blood pressure were developed or propagated, some of which incorporated standard gravity in their definitions.

Earth

Earth's surfaceterrestrialworld
In the US weather code remarks, three digits are all that are transmitted; decimal points and the one or two most significant digits are omitted: 1013.2 mbar is transmitted as 132; 1000.0 mbar is transmitted as 000; 998.7mbar is transmitted as 987; etc. The highest sea-level pressure on Earth occurs in Siberia, where the Siberian High often attains a sea-level pressure above 1050 mbar, with record highs close to 1085 mbar. Surface pressure is the atmospheric pressure at a location on Earth's surface (terrain and oceans).
The atmospheric pressure at Earth's sea level averages 101.325 kPa, with a scale height of about 8.5 km.

Typhoon Tip

TipSuper Typhoon Tip1979
The lowest non-tornadic atmospheric pressure ever measured was 870 hPa (0.858 atm; 25.69 inHg), set on 12 October 1979, during Typhoon Tip in the western Pacific Ocean.
After passing Guam, Tip rapidly intensified and reached peak sustained winds of 305 km/h and a worldwide record-low sea-level pressure of 870 hPa on October 12.

Weather

weather conditionsweather systemselements
Atmospheric pressure varies widely on Earth, and these changes are important in studying weather and climate.
A hot surface warms the air above it causing it to expand and lower the density and the resulting surface air pressure.

Dead Sea

The Dead SeaSalt SeaDead Sea Panorama Complex
The Dead Sea, the lowest place on Earth at 430 m below sea level, has a correspondingly high typical atmospheric pressure of 1065hPa.
Given the higher atmospheric pressure, the air has a slightly higher oxygen content (3.3% in summer to 4.8% in winter) as compared to oxygen concentration at sea level.

Vapor pressure

vapour pressuresaturation vapor pressureequilibrium vapor pressure
The boiling point is the temperature at which the vapor pressure is equal to the atmospheric pressure around the water.
The atmospheric pressure boiling point of a liquid (also known as the normal boiling point) is the temperature at which the vapor pressure equals the ambient atmospheric pressure.

Meteorology

meteorologicalmeteorologistmeteorologists
Meteorological phenomena are described and quantified by the variables of Earth's atmosphere: temperature, air pressure, water vapour, mass flow, and the variations and interactions of those variables, and how they change over time.

Ocean

marineoceansmaritime
Surface pressure is the atmospheric pressure at a location on Earth's surface (terrain and oceans).
Typical seawater freezes at around −2 °C at atmospheric pressure.

Pressure measurement

manometerpressure gaugegauge pressure
Tire pressure and blood pressure are gauge pressures by convention, while atmospheric pressures, deep vacuum pressures, and altimeter pressures must be absolute.

Pressure cooking

pressure cookerpressure cookerspressure cooked
Cooking at high elevations, therefore, requires adjustments to recipes or pressure cooking.
At a pressure of 1 bar or approximately 100 kPa above the existing atmospheric pressure, water in a pressure cooker will reach a temperature of 121 C. The boiling temperature of water (and water-based liquids) is determined by the ambient atmospheric pressure.