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  2. Atmospheric pressure - Wikipedia

    en.wikipedia.org/wiki/Atmospheric_pressure

    Atmospheric pressure, also known as air pressure or barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as 101,325 Pa (1,013.25 hPa ), which is equivalent to 1,013.25 millibars , [ 1 ] 760 mm Hg , 29.9212 inches Hg , or 14.696 psi . [ 2 ]

  3. Pressure system - Wikipedia

    en.wikipedia.org/wiki/Pressure_system

    A low-pressure area is a region where the atmospheric pressure at sea level is below that of surrounding locations. Low-pressure systems form under areas of wind divergence that occur in the upper levels of the troposphere. [1] The formation process of a low-pressure area is known as cyclogenesis. [2]

  4. Magdeburg hemispheres - Wikipedia

    en.wikipedia.org/wiki/Magdeburg_hemispheres

    The Magdeburg hemispheres are a pair of large copper hemispheres with mating rims that were used in a famous 1654 experiment to demonstrate the power of atmospheric pressure. When the rims were sealed with grease and the air was pumped out, the sphere contained a vacuum and could not be pulled apart by teams of horses. Once the valve was opened ...

  5. Hadley cell - Wikipedia

    en.wikipedia.org/wiki/Hadley_cell

    Hadley's model of the global atmospheric circulation being characterized by hemisphere-wide circulation cells was also challenged by weather observations showing a zone of high pressure in the subtropics and a belt of low pressure at around 60° latitude. This pressure distribution would imply a poleward flow near the surface in the mid ...

  6. Polar easterlies - Wikipedia

    en.wikipedia.org/wiki/Polar_easterlies

    In the study of Earth's atmosphere, polar easterlies are the dry, cold prevailing winds that blow around the high-pressure areas of the polar highs at the North and South Poles. [1] Cold air subsides at the poles creating high pressure zones, forcing an equatorward outflow of air; that outflow is then deflected westward by the Coriolis effect.

  7. Trough (meteorology) - Wikipedia

    en.wikipedia.org/wiki/Trough_(meteorology)

    A trough is an elongated region of relatively low atmospheric pressure without a closed isobaric contour that would define it as a low pressure area. Since low pressure implies a low height on a pressure surface, troughs and ridges refer to features in an identical sense as those on a topographic map. Troughs may be at the surface, or aloft, at ...

  8. Low-pressure area - Wikipedia

    en.wikipedia.org/wiki/Low-pressure_area

    In meteorology, a low-pressure area, low area or low is a region where the atmospheric pressure is lower than that of surrounding locations. It is the opposite of a high-pressure area . Low-pressure areas are commonly associated with inclement weather (such as cloudy, windy, with possible rain or storms), [ 1 ] while high-pressure areas are ...

  9. Atmospheric thermodynamics - Wikipedia

    en.wikipedia.org/wiki/Atmospheric_thermodynamics

    Atmospheric thermodynamics is the study of heat-to-work transformations (and their reverse) that take place in the Earth's atmosphere and manifest as weather or climate. . Atmospheric thermodynamics use the laws of classical thermodynamics, to describe and explain such phenomena as the properties of moist air, the formation of clouds, atmospheric convection, boundary layer meteorology, and ...