Abstract
We investigate transmission through falling snow using a 3D imaging lidar at 1.56-μm wavelength. The lidar is based on the time-correlated single-photon counting technique. Experimental transmission data are compared with Mie theory transmission calculations based on snow particle size distribution simultaneously measured with a laser disdrometer. The calculations were performed in two ways, using the Beer–Lambert approach where all radiation interacting with a hydrometeor is considered extinct and an approach that includes effects of the forward scattering. Comparison of these two methods shows that inclusion of the contribution from forward scattering gives better agreement between experiment and calculations than using extinction only. When comparing the results using scattering calculations with a curve fit approach based on precipitation rate, it is evident that both the Beer–Lambert approach and the forward scattering approach give a much better correlation between experiment and calculations than relying on precipitation rate, as measured with the disdrometer, only.
Highlights
Optical attenuation in degraded visual environments, such as precipitation, can severely affect the performance of laser-based systems
Our results show that basing the transmission calculations on measured hydrometeor particle size distribution (PSD) and hydrometeor scattering behavior give a good agreement between calculations and measured signal levels in the case of falling snow
The snow PSD was characterized with a laser disdrometer providing a point-wise characterization of the precipitation, and the PSDs were used to calculate transmission efficiencies based on Mie scattering behavior
Summary
Optical attenuation in degraded visual environments, such as precipitation, can severely affect the performance of laser-based systems. Further investigating signal attenuation within the FSO context, Korai et al.[2] presented work on a model for attenuation effects due to rain. In their work, they integrated FSO attenuation calculations with a global rainfall model, which given local rainfall statistics can generate precipitation rate preserving maps of rainfall events based on a number of synthetic rain fields. Roy et al discussed the interaction between falling snow and a 3D lidar scanner In their work, they calculated the lidar signal in model snowfalls, and based on their findings they discussed a filtering algorithm for suppression of noise due to scattering from the snow particles.[4]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
