Assessment of automated quality control of MOR measurements by the FD12P sensor

Koninklijk Nederlands Meteorologisch Instituut, M. de Haij
De Bilt : KNMI

KNMI operates the Vaisala FD12P present weather sensor for automated visibility observations in its national meteorological network. The FD12P is a forward scatter sensor that measures the scattering of light (875 nm) in a sample volume of approximately 0.1 dm3, located at the intersection of the transmitter and receiver beams. This volume is located approximately 1.75 m above the surface (2.5 m at airports). The extinction is derived from the scattered sifnal, by assuming a fixed relation between the amount of scatter and the extinction. The sensor also determines the precipitation type, duration and intensity. KNMI employs as well transmissometers and HSS forward scatter sensors for the observations of visibility at some locations. These sensors will be replaced by a FD12P in the near future and are not considered in this document.

IV, 37 p. : fig., tab. ; 30 cm
(Technical report = Technisch rapport ; TR-298)
With ref.
MOR = Meteorological Optical Range