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Proceedings Paper

Visibility in low clouds and its impact on FSO links
Author(s): M. Ammar Al-Habash; Janae Nash; Jeff Baars; Michael Witiw; Kenneth W. Fischer; Kenneth N. Desmet
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Paper Abstract

Fog and low clouds are the two atmospheric elements with the greatest impact on the performance of a free space optical (FSO) network. Predicting the effects of low clouds and ground based fog on FSO equipment performance is a challenging exercise. Usually, surface visibility records from airports in proximity to the deployment area are used to calculate the link availability. However, very little data are available on visibility within clouds, which have a larger impact on elevated links. To estimate the visibility in low clouds we have deployed visibility sensors at three different heights (33, 119, 188 meters above mean sea level) and a ceilometer in San Francisco from June to October of 2001. The data collected show substantial difference between the visibility reported at San Francisco International Airport (SFO) and the visibility recorded by our sensors in downtown San Francisco. More importantly, the data indicate a greater prevalence of low clouds downtown than at the airport.

Paper Details

Date Published: 9 December 2002
PDF: 10 pages
Proc. SPIE 4821, Free-Space Laser Communication and Laser Imaging II, (9 December 2002); doi: 10.1117/12.462009
Show Author Affiliations
M. Ammar Al-Habash, Terabeam Corp. (United States)
Janae Nash, Terabeam Corp. (United States)
Jeff Baars, Terabeam Corp. (United States)
Michael Witiw, Terabeam Corp. (United States)
Kenneth W. Fischer, Terabeam Corp. (United States)
Kenneth N. Desmet, Terabeam Corp. (United States)


Published in SPIE Proceedings Vol. 4821:
Free-Space Laser Communication and Laser Imaging II
Jennifer C. Ricklin; David G. Voelz, Editor(s)

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