What is the contraction for 'Vertical visibility'?

Vertical visibility is a term used in aviation and meteorology to describe the distance one can see vertically into the atmosphere, especially relevant in conditions such as fog or overcast skies where horizontal visibility is limited. The contraction for vertical visibility is represented as "VV." This shorthand is widely accepted within aviation communications and documentation, allowing for quick reference on official reports such as meteorological observations or aerodrome reports.

The other choices do not accurately represent the term vertical visibility in standard aviation terminology. For instance, "VT" typically refers to vertical time, "VZ" is not commonly used in this context, and "VC" could suggest visibility condition but is not a recognized contraction for vertical visibility. Hence, "VV" stands out as the correct and standardized contraction.