It is the force exerted on a surface by the air above it as gravity pulls it to Earth.Atmospheric pressure is commonly measured with a barometer. p If you have questions about licensing content on this page, please contact ngimagecollection@natgeo.com for more information and to obtain a license. This is, in part, because the Earth is not equally heated by the Sun. ideal gas law Even above the Krmn line, significant atmospheric effects such as auroras still occur. The exosphere is too far above Earth for meteorological phenomena to be possible. Atmospheric pressure is expressed in several different systems of units: millimetres (or inches) of mercury, pounds per square inch (psi), dynes per square centimetre, millibars (mb), standard atmospheres, or kilopascals. It is the coldest place on Earth and has an average temperature around 85C (120F; 190K).[26][27]. The atmosphere that surrounds Earth has weight and pushes down on anything below it. [25] Although the thermosphere has a high proportion of molecules with high energy, it would not feel hot to a human in direct contact, because its density is too low to conduct a significant amount of energy to or from the skin. [citation needed]. Colder objects emit less radiation, with longer wavelengths. Temperature Temperature is a physical quantity that expresses hot and cold. Global atmospheric circulation is driven by the uneven heating of the Earth's surface by the Sun, which creates temperature and pressure differences that cause air to move. Geometric altitude vs. temperature, pressure, density, and the speed of sound derived from the 1962 U.S. Standard Atmosphere. The dew point is the temperature at which condensationoccurs. Surface Pressure | Earthdata It lies above the troposphere and is separated from it by the tropopause. Different molecules absorb different wavelengths of radiation. We don't feel this pressure because our bodies push an equal amount of pressure outward. 1 T Our editors will review what youve submitted and determine whether to revise the article. = Standard sea-level pressure, by definition, equals 760 mm (29.92 inches) of mercury, 14.70 pounds per square inch, 1,013.25 103 dynes per square centimetre, 1,013.25 millibars, one standard atmosphere, or 101.325 kilopascals. Interactive global map of current atmospheric and ocean surface conditions. 0 Areas where the air is warmed often have lower pressure because the warm air rises. In aviation weather reports (METAR), QNH is transmitted around the world in hectopascals or millibars (1 hectopascal = 1 millibar), except in the United States, Canada, and Japan where it is reported in inches of mercury (to two decimal places). For numerical reasons, atmospheric models such as general circulation models (GCMs) usually predict the nondimensional logarithm of surface pressure. The pressure at 270,000 metres (106 mb) is comparable to that in the best man-made vacuum ever attained. Variations about these values are quite small; for example, the highest and lowest sea-level pressures ever recorded are 32.01 inches (in the middle of Siberia) and 25.90 inches (in a typhoon in the South Pacific).