P1.7
Directional visibility measurements with the Vaisala Ceilometer
Antti K. Piironen, Vaisala Oyj, Helsinki, Finland; and J. Rasanen and J. Lonnqvist
Vaisala's CT25K ceilometer internally calculates the extinction coefficient over the range of interest. From this, a value for visibility (Meteorological Optical Range) can be retrieved. Pointing the beam vertical or near-vertical provides a vertical visibility value. Tilting the instrument allows measuring directional visibility.
Inverting a backscatter profile for obtaining an extinction coefficient profile is a classical problem, and particularly difficult in the close range where the beam overlap and multiple scattering characteristics of a typical bistatic lidar are uncertain. We studied the accuracy of our monostatic coaxial ceilometer lidar and its visibility retrieval scheme in the case of a nearly horizontal pointing direction. Performance was validated against reference transmissometer measurements. Results will be presented and discussed.
Poster Session 1, Poster Session
Tuesday, 11 January 2000, 6:00 PM-7:30 PM
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