The correct answer is option 2, air current.

Wind refers to the horizontal movement of air, while air current specifically refers to the vertical movement of air. Wind can blow in different directions, such as north to south or east to west, but air current represents the upward or downward movement of air.

Option 3, air turbulence, refers to a state of irregular and chaotic air movement, often causing turbulence in an aircraft. It is not specific to vertical movement, as turbulence can occur in any direction.

Option 4, air mobility, is not a commonly used term to describe vertical movement of air.

Therefore, option 2, air current, is the most accurate term to describe the vertical movement of air.