00000nam 2200000zi 4500 9.939809 CaOODSP 20241127112631 m o d f cr bn||||||||| 240625t19771978onca ob f000 0 eng d 0662020634 (print) CaOODSP eng rda CaOODSP eng eng fre En57-58/856-1977E-PDF En57-20/856 Sheppard, B. E. (Brian E.) author. Calibration of a videograph against meteorological optical range derived from standard AES transmissometer measurements / by Brian E. Sheppard = Étalonnage d'un vidéographe par rapport à la portée optique météorologique déterminée d'après des mesures effectuées avec le transmissiometre étalon du SEA / par Brian E. Sheppard. Étalonnage d'un vidéographe par rapport à la portée optique météorologique déterminée d'après des mesures effectuées avec le transmissiometre étalon du SEA Downsview, Ontario : Fisheries and Environment Canada, Atmospheric Environment Service = Pêches et environnement Canada, Service de l'environnement atmosphérique, 1977. ©1978 1 online resource (9 pages, 2 unnumbered pages) : illustrations. text txt rdacontent computer c rdamedia online resource cr rdacarrier Technical memoranda, 0068-7804 ; TEC 856 ISSN of series should read: 0708-2878. "Published under the authority of the Assistant Deputy Minister"--Cover. "UDC: 551.508.92"--Cover. "12 December 1977"--Cover. Digitized edition from print [produced by Environment and Climate Change Canada]. Includes bibliographical references (page 5). "A Videograph Visibility Meter is calibrated against Meteorological Optical Range (MOR) derived from standard Atmospheric Environment Service transmissometer measurements. We found that the Videographmeasures MOR to within a factor of two with 99% confidence. This error is as large as that found for the Videograph - prevailing visibility calibration data of 1970-1. A possible explanation of this unexpectedresult is the omission of obstruction to vision distinctions from the analysis. We recommend re-locating this experiment to Toronto International Observing Site to permit the inclusion of prevailing visibility, obstruction to vision and ambient illumination in the data base. With this additional information we can calibrate the Videograph or other scatter-type visibility sensors in terms of MOR for individual weather conditions. Also, we can calculate the meteorological observer's visual contrast threshold as a function of ambient illumination"--Abstract. Includes abstracts in English and French. Visibility Measurement Instruments Calibration. Meteorological instruments Calibration. Visibilité Mesure Instruments Étalonnage. Météorologie Instruments Étalonnage. Canada. Atmospheric Environment Service, issuing body. Technical memoranda (Canada. Atmospheric Environment Service) TEC 856. (CaOODSP)9.934501 PDF 667 KB https://publications.gc.ca/collections/collection_2024/eccc/en57/En57-58-856-1977-eng.pdf