Which is not a mechanism that causes air masses to rise?

The mechanism of sublimation is not responsible for causing air masses to rise. Sublimation refers to the process where a solid changes directly into a gas without passing through the liquid phase, such as when ice turns directly into water vapor. This process involves a change in phase of water and does not directly affect the vertical movement of air masses in the atmosphere.

In contrast, convection involves the vertical movement of air due to heating at the Earth’s surface; warmer air becomes less dense and rises. Convergence occurs when air masses move toward each other and are forced to rise due to the accumulation of air in a smaller area. Orographic lift happens when air masses are pushed upward by geographical features like mountains, resulting in rising air. Each of these mechanisms actively contributes to lifting air masses, whereas sublimation does not have a role in this dynamic.