<prompt> Answer this question truthfullyWhat does atmospheric pressure gradient mean?  <response>: <reason> In atmospheric sciences 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 changes the most rapidly around a particular location. The pressure gradient is a dimensional quantity expressed in units of pressure per unit length. The SI unit is pascal per metre Pam. 