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Pressure

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Pressure
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Conjugate variables
of thermodynamics ...

 


Pressure Activity scaffolding activity
Introduction:
Though you may not realize it, the air has weight. All the air molecules in the atmosphere exert a force, or pressure, on our bodies.

Pressure A type of stress characterized by uniformity in all directions. In dynamics, it is that part of the stress tensor that is independent of viscosity and depends only upon the molecular motion appropriate to the local temperature and density.

Low pressure systems or mid-latitude cyclones are atmospheric circulations that rotate clockwise in the Southern Hemisphere (anti-clockwise in the Northern Hemisphere).

Barotropic System - A weather system in which temperature and pressure surfaces are coincident, i.e., temperature is uniform (no temperature gradient) on a constant pressure surface.

Atmospheric pressure is the force exerted by the weight of the atmosphere, also known as barometric pressure. The internationally recognized unit for measuring this pressure is the kilopascal.
AURORA (AURORA BOREALIS) ...

pressure force"(Or pressure-gradient force.) The force due to differences of pressure within a fluid mass.

pressure-type anemometer
Any instrument that measures the wind speed by measuring the pressure exerted by the wind upon the sensor element of that instrument. Examples include the pressure plate anemometer and the Pitot tube.
psychrometer ...

pressure altitude—The altitude in the standard atmosphere at which the pressure is the same as at the point in question.

Pressure Gradient-The amount of pressure change occurring over a given distance.
Radiosonde-A lightweight package of weather instruments fitted with a radio transmitter and carried up into the atmosphere by a balloon.

Pressure - a force per unit area or a stress characterized by uniformity in all directions
Pressure Gradient - the change in pressure over a given distance at a given time ...

pressure - 1. A type of stress characterized by uniformity in all directions. As a measurable on a surface, the net force per unit area normal to that surface exerted by molecules rebounding from it.

Pressure is usually measured in millibars, 1 mb = 103 dyne/cm2. Distance is conveniently measured in the length of a degree of latitude, which is 111 km or 69 mi. Then, a pressure gradient of 1 mb per degree of latitude is 8.993 x 10-5 dyne/cm2/cm.

Pressure*
bayre
0.1 pascal
CGSA Acronym: Cellular Geographic Serving Area Telephony: A geographic cellular coverage region defined by the FCC. The two types are Metropolitan Statistical Areas (MSA's) and Rural Statistical Areas (RSA's).

PRESSURE ALTITUDE
The altitude in standard atmosphere at which a given pressure will be observed. It is the indicated altitude of a pressure altimeter at an altitude setting of 29.

Pressure gradient wind
The wind that results from the pressure gradient. The greater the pressure gradient between two points, the greater the wind.

PRESSURE ALTITUDE - The apparent altitude which varies as air pressure (and this density) varies.
PROPELLER - A device with angled blades that is spun by the engine so as to push air backwards and thereby create forward motion or thrust.

PRESSURE TENDENCY: (BAROMETRIC TENDENCY) The change in barometric pressure within a specified period of time (typically 3 hours for meteorological observations).

PRESSURE: The force exerted by the interaction of the atmosphere and gravity. Also known as atmospheric pressure.
PTWC: Pacific Tsunami Warning Center, located in Honolulu, HI.
PVA: Positive Vorticity Advection.

Pressure The force exerted by the weight of the atmosphere, also known as atmospheric pressure. When measured on a barometer, it is referred to as barometric pressure and it is expressed in inches of mercury, millibars, or kiloPascals.

Pressure: the exertion of force upon a surface by a fluid (e.g., the atmosphere) in contact with it.
Primary pollutant: substances that are pollutants immediately on entering the atmosphere. Compare secondary pollutant.
Q ...

Pressure- a measure of the weight of the air, that is usually measured with a barometer in meteorology.
- Q -
Quality Of Snow- the amount of ice in a snow sample expressed as a percent of the weight of the sample.

Pressure gradient- The rate of decrease of pressure per unit of distance.

Pressure gradient force: the force caused by the change in atmospheric pressure per unit of horizontal distance, and acting in the direction in which pressure changes most rapidly.

Pressure changes:(in coastal station reports/3 hours is a 'standard' time period used in synoptic meteorology in mid/high latitudes.)
Steady
Change less than 0.1 mbar in past 3 hours ...

Pressure Gradient Force- Force acting on air that causes it to move from areas of higher pressure to areas of lower pressure.

Pressure Pressure is the force exerted on an object by something else. For example, when pressing a tack into the wall, you are exerting pressure on the wall through the tack.

A pressure unit of 1000 dynes cm-2, often used for reporting atmospheric pressure where one millibar equals 1 hectopascal (hPA).
Mirage(6) ...

Low pressure systemLow pressure systems have a relatively low air pressure in it's center. With it's fuming air masses development of clouds and precipitations is favoured.

air pressure: barometric pressure; weight of the atmosphere at a particular point of interest.
anomaly 1: unusual temperature or precipitation for a given region over a specified period. Also see anomaly 2 (Orbital Mechanics section).

Air Pressure - or atmospheric pressure. air pressure is the force exerted on a surface by the weight of the air above it.

Air Pressure:
The weight of the atmosphere pressing down on the Earth's surface. The effect is caused by gravity. Also called 'atmospheric pressure'.
Albedo: ...

Air pressure
The cumulative force exerted on any surface by the molecules composing air.
Albedo
The percent of radiation returning from a surface compared to that which strikes it.

low pressure- a system in which air pressure decreases toward the center, associated with unsettled weather, usually formed by a mass of warm air being forced up by cold air.

Air Pressure - The force exerted by the weight of a column of air above a given point.

LOW PRESSURE SYSTEM An area of a relative pressure minimum that has converging winds and rotates in the same direction as the earth. This is counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.

Air Pressure - The pressure exerted by the weight of air above a given point, usually expressed in millibars (mb) or inches of mercury (in. Hg).

The pressure value to which an aircraft altimeter scale is set so that it will indicate the altitude above mean sea level of an aircraft on the ground at the location for which the value was determined.
ALTITUDE ...

The pressure of the atmosphere as indicated by a barometer.
Barotropic System ...

Air Pressure - same as atmospheric pressure.
Air Quality - a measure of the cleanliness of air described in terms of levels of contaniments in air especialy with regard to their potential effects on human health.

low pressure system: area of minimum air pressure, and cyclonic air movement.

Low Pressure System - A whirling mass of warm, moist air that generally brings stormy weather with strong winds. When viewed from above, winds spiral into a low-pressure center in a counterclockwise rotation in the Northern Hemisphere.

Low Pressure Area - or a "Low" An area of low atmospheric pressure that has a closed counter-clockwise circulation in the Northern Hemisphere. Also known as a cyclone.
-M- ...

PG- Pressure gradient. Tightening pressure gradient indicates stronger winds.

LOW PRESSURE - A region of low air pressure in the atmosphere. Commonly associated with storms and cyclones.

P1560 Pressure anomaly
Difference between the mean pressure at a site and the mean pressure for the whole parallel of latitude on which the site is located.

Constant Pressure Maps: A weather map of a particular constant pressure surface, such as the 50 kPa or 500 mb surface, in which atmospheric pressure is uniform everywhere.

CONSTANT PRESSURE CHART
A chart of a constant pressure surface in which atmospheric pressure is uniform everywhere at any given moment. Elements may include analyses of height above sea level, wind, temperature, and humidity.

Atmospheric pressure
The amount of force exerted over a surface area, caused by the weight of air molecules above it. As elevation increases, fewer air molecules are present. Therefore, atmospheric pressure always decreases with increasing height.

Atmospheric Pressure: Also called barometric pressure. It is the pressure exerted by the atmosphere as a consequence of the gravitational attraction occurring over a column of air at a specific point.
Air: Mixture of gases which form the atmosphere.

Atmospheric Pressure
(pressure) Pressure (force per unit area) exerted by the atmosphere on any surface by virtue of its weight; ...

Eye: The low pressure center of a tropical cyclone. Winds are normally calm and sometimes the sky clears.

Normally high pressure is located in the eastern Pacific off the shores of Ecuador and Peru, likewise, low pressure is situated over the western Pacific in the area of Indonesia and Australia.

Q
QFE Atmospheric pressure at field elevation. QNH Same as altimeter setting. Quadrant electrometer A very sensitive electrostatic electrometer for measuring small potential differences.

Closed low - A low pressure area with a distinct center of cyclonic rotation which can be completely encircled by one or more isobars or other contour lines.

The scale categorizes potential damage based on barometric pressure wind speeds, and storm surge. See the scale. ST. ELMO'S FIRE A luminous, and often audible, electric discharge that is intermediate in nature.

RadiosondeAn instrument that is carried aloft by a balloon to send back information on atmospheric temperature, pressure and humidity by means of a small, expendable radio transmitter.

CenterGenerally speaking, the vertical axis of a tropical cyclone, usually defined by the location of minimum wind or minimum pressure. The cyclone center position can vary with altitude.

Trade WindsPersistent tropical winds that blow from the subtropical high pressure centers towards the equatorial low.

It represents the maximum amount of water vapor that the air can hold at any given temperature and pressure. saturation vapor pressure The maximum amount of water vapor necessary to keep moist air in equilibrium with a surface of pure water or ice.

See also: Air, Temperature, Surface, Weather, High