Measurement and Analysis of offshore fog occurrences

The occurrence of fog presents a hazard to marine operations in many areas. While this hazard is well known to experienced mariners, it is important to describe and document the nature and extent of their occurrence. The used sensor is a forward-scatter sensor. Those sensors have a projector that transmits a beam of light. The amount of light scattered forward into a receiver is measured. This sensor is competitive in accuracy, reliability, and cost with the other types of sensors. The Fog occureneces were analyzed to gather inforamtion about: the duration, the velocity of the visibility change and the probabilty of short versus long fog events.

Fog events were detected when the visibility reaches values below the limit of 1000 m. The fog events show in most cases a rapid start and end. A slow beginning of fog events was rare.