Which term refers to the distance over which pressure changes occur?

The term that refers to the distance over which pressure changes occur is the pressure gradient. This concept is crucial in meteorology as it describes how pressure varies over a specific distance in the atmosphere. A steeper pressure gradient indicates that there is a rapid change in pressure over a short distance, which can lead to stronger winds. This is a key factor in understanding atmospheric dynamics and forecasting weather patterns.

In contrast, isobar spacing represents how closely the isobars—lines of constant pressure on a weather map—are situated to one another. While it relates to pressure differences, it does not specifically quantify the distance over which those changes occur. Wind velocity measures the speed of air movement but does not address pressure changes directly. The altitude factor refers to the influence of height above sea level on weather conditions and atmospheric pressure but does not define the distance over which pressure varies. Therefore, pressure gradient is the most accurate term to describe this phenomenon.