Contour line future weather patterns. Isobars are commonly used in television weather reporting. Isallobars are lines joining points of equal pressure change during a specific time interval. These can be divided into "anallobars", lines joining points of equal pressure increase during a specific time interval, and "katallobars", lines joining points of equal pressure decrease. In general, weather systems move along an axis joining high and low isallobaric centers. Isallobaric gradients are important components of the wind as they increase or decrease the geostrophic wind. An isopycnal is a line of constant density. An "isoheight" or "isohypse" is a line of constant geopotential
Ambient pressure other circumstances be measured in pounds per square inch (psi) or in standard atmospheres (atm). The ambient pressure at sea level is approximately one atmosphere, which is equal to , which is close enough for bar and atm to be used interchangeably in many applications. Pressures are given in terms of the normal ambient pressure experienced by humans — standard atmospheric pressure at sea level on earth. Ambient pressure The ambient pressure on an object is the pressure of the surrounding medium, such as a gas or liquid, in contact with the object. Within the atmosphere, the ambient pressure decreases