When the visibility is not the same around the horizon circle, it is said to be ____.

When visibility is not the same around the horizon circle, it is referred to as "non-uniform" because it indicates that there are differences in visibility at various points around the observer's horizon. This term effectively conveys that the conditions affecting visibility, such as fog, haze, precipitation, or obstructions, are inconsistent in their distribution.

The non-uniformity reflects how factors like terrain, weather systems, and atmospheric conditions can create varying visibility levels. For example, one direction may have clear visibility, while another direction may be significantly reduced due to localized weather phenomena. This differentiation is crucial for pilots and aviation professionals, as uneven visibility can impact flight safety and decision-making.

Other terms like "uniform" or "consistent" suggest a homogenous visibility where conditions are the same in all directions, which is not applicable in this scenario. "Variable" could imply changes in visibility, but it does not specifically capture the concept of inconsistency around the horizon circle as effectively as "non-uniform." Thus, "non-uniform" is the most precise term for describing this particular situation.