The Development of the Research in Digital Visibility Instruments and the Related Comparative Experiments

摘要

The observation automation of cloud, visibility, and weather phenomena are principal issue to solve in the modern meteorological observation field. In the late 20th century, scientists have started to develop a kind of digital visibility automatic monitor, which has adopted advanced digital photographic technology and image recognition technology, based on the definition of visibility and fully imitating the human eye observing visibility principle ( Steffens C, 1949 ). Undoubtedly, the digital visibility automatic monitor is the best instrument to replace the manual observation of visibility ( homas 1994 ). This article briefly introduces the methods of visual and instrumental observation of visibility, and elaborates the basis of the Digital Photograph Device System ( Xingsheng, 1999 ), its latest development, and the comparative results between Finnish Vaisala visibility instrument and manual observation ( Jingli, 2002 ). In the end, the article reaches an error analysis conclusion and discusses about the problems and further improving measures.