In atmospheric science (meteorology, climatology and related fields), the pressure gradient (typically of air, more generally of any fluid) is a physical quantity that describes in which direction and at what rate the pressure increases the most rapidly around a particular location. The pressure gradient is a dimensional quantity expressed in units of Pa/m
Mathematically, it is obtained by applying the del operator to a pressure function of position. The negative gradient of pressure is known as the force density
In the Petroleum Geology and Petrochemical sciences pertaining to oil wells, and more specifically within Hydrostatic Pressure, pressure gradients refer to the gradient of vertical pressure in a column of fluid within a wellbore generally expressed in psi/ft. this column of fluid is subject to the compound pressure gradient of the overlying fluids. The path and geometry of the column is totally irrelevant, only the vertical depth of the column has any relevance on the vertical pressure of any point within its column and the pressure gradient for any given true vertical depth.