VISIBLE EXTINCTION MEASUREMENTS IN RAIN AND SNOW USING A FORWARD SCATTER METER (paper presented at the Fourth Propagation Engineering Conference, Orlando, Florida, 3 - 4 April 1991)

  1. Hutt, D.L.
  2. Oman, J.
Corporate Authors
Defence Research Establishment Valcartier, Valcartier QUE (CAN);Laval Univ, Quebec QUE (CAN) Departement de Physique
A forward scatter meter is a convenient and accurate method to measure the local visible extinction coefficient in fog and haze. The device works by illuminating with near IR light a sample volume of air and measuring the intensity scattered in the angular range of 27 to 42 degrees. The scattered intensity is well correlated to the extinction coefficient of fog regardless of the fog droplet size distribution. The forward scatter meter also gives meaningful measurements during rain and snowfall. A comparison of extinction measurements made with a narrow beam transmissometer and the forward scatter meter have been made. The results show that during rain the forward scatter meter extinction coefficient is from 25% to 50% greater than that measured with the transmissometer. During snowfall the forward scatter meter extinction coefficient is about 10% to 40% less than that measured with the transmissometer. TRUNCATED
Date of publication
15 Apr 1991
Number of Pages
Reprinted from
Proceedings of SPIE - The International Society for Optical Engineering, vol 1487, 1991, p 312-323
Hardcopy;Originator's fiche received by DSIS

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