What establishes the force that causes air to move from higher pressure to lower pressure?

The force that causes air to move from areas of higher pressure to areas of lower pressure is established by the pressure gradient. A pressure gradient is the difference in atmospheric pressure that exists between two locations, and it drives the wind by creating a force that pushes air from high-pressure areas to low-pressure areas in an attempt to equalize the pressure differences.

This movement of air is fundamental to understanding wind patterns and is influenced by various meteorological phenomena. In the context of weather, the greater the difference in pressure over a given distance, the stronger the wind that results. This concept is central to weather systems and understanding how air circulation works on a larger scale.

The other options—temperature gradient, dew point gradient, and humidity gradient—relate to different atmospheric properties and phenomena, but they do not specifically establish the force responsible for the horizontal movement of air associated with pressure differences. While temperature gradients can influence atmospheric pressure (via thermal expansion or contraction), the direct mechanism for air movement is the pressure gradient itself. Similarly, dew point and humidity gradients pertain to moisture content and saturation in the air but do not dictate the direction of airflow in terms of pressure differences.