What does a surface observation report indicate when it includes "RVR"?

The specific term "RVR" in a surface observation report refers to "Runway Visual Range." This measurement is particularly crucial in aviation as it indicates the visibility conditions specifically in the immediate vicinity of runways. RVR is an essential factor for pilots and air traffic control, as it helps determine whether conditions are safe for takeoff and landing. It provides an objective measure of how far a pilot can see down the runway, which is vital during low visibility situations, such as fog, rain, or snow.

Runway Visual Range is typically measured using transmissometers and is reported in meters or feet, allowing pilots to ascertain if they can safely proceed during operations. This precise data ensures that necessary precautions are taken when visibility is lower than standard requirements, directly impacting flight safety and operational efficiency.

The other terms in the options do not pertain specifically to runway conditions or are misrepresented, making them less relevant in the context of aviation safety concerning runway operations.