Topic summary
atmospheric
Extracted from the Wikipedia article Atmosphere.
Conditions
An atmosphere in hydrostatic equilibrium consists of a balance between the air pressure created by the motions of the molecules, and the restraining force of gravity that prevents the molecules from escaping. The pressure decreases in altitude, producing a pressure-gradient force. Atmospheric pressure is the force (per unit-area) perpendicular to a unit-area of planetary surface, as determined by the weight of the vertical column of atmospheric gases. In said atmospheric model, the atmospheric pressure, the weight of the mass of the gas, decreases at high altitude because of the diminishing mass of the gas above the point of barometric measurement. Air pressure varies by place and time due to meteorological conditions and atmospheric waves.