1. V.E. Zuev Institute of Atmospheric Optics SB RAS Tomsk Russia
Amplification of the Mean Echo Signal Power of a Coherent Lidar in a Turbulent Atmosphere
V.A. Banakh, A.V. Falits
V.E. Zuev Institute of Atmospheric Optics SB RAS Tomsk Russia

2. Backscatter amplification effect in random media
M.S. Belen’kii, V.L. Mironov, Soviet Journal of Quantum Electronics,1973
A.G. Vinogradov, Yu.A. Kravtsov, and V.I. Tatarskii, Radiophysics and Quantum Electronics, 1973
V.A. Banakh, V.L. Mironov “Lidar in a turbulent atmosphere”, 1987
is the intensity correlation function of a spherical wave incident on a scatterer
is maximal as compared to
A.S. Gurvich. Russian Federation Patent No , 2012
I.A. Razenkov, V.A.Banakh, A.I. Nadeev. Russian Federation Patent No , 2015

3. Two receiver channels (BSA) lidar for estimation of the strength of refractive turbulence
Ratio of the mean powers of echo signals in the channels determines the coefficient of backscatter amplification depending on the turbulence strength

4. Scheme of the experiment
Comparison of temporal variations of the amplification coefficient N and variance of the optical image jitter registered on a probing path The variance is proportional to the integral value of the Cn2 on a probing path.

5. Cn2 measured by sonic meteostations 16-17 June 2017. Path 2 km.
Amplification coefficient N measured by BSA lidar simultaneously with the sonic meteostations.
Cn2 measured by the optical measurer (orange) and sonic meteostations (green and blue). Amplification coefficient (black).

6. Experimental overview
Screen
Stream Line
Coherent Doppler Lidar
Meteostation 1
100 m
Meteostation 3
Meteostation 2
400 м
Distance between
lidar and screen is 495 м

7. Mean power of a coherent lidar echo signal

8. Computer simulation of and for the StreamLine lidar parameters on a 500 m path

9. Mean power of the StreamLine lidar echo signal

10. Mean power for monostatic and bistatic schemes
Mean power for monostatic and bistatic schemes. Calculations for the StreamLine lidar beam parameters

11. The structure constant of turbulent fluctuations of the refractive index of air and the signal-to-noise ratio of the Stream Line lidar as functions of time
Local time, h: min

12. Experiment on 9 June 2018. 450 m path

13. SNR versus Cn2
SNR
SNR

14. All experimental data June 2017
Correlation coefficient
0.91
0.71
0.81
0.86
0.51
0.72
SNR

15. Temporal variations of SNR for StreamLine lidar and amplification coefficient N for BSA lidar

16. Conclusions
Mean power of the echo signal of a coherent lidar can increase in a turbulent atmosphere because of the effect of backscatter amplification in random media
On surface paths temporal variations of SNR of a coherent lidar follow to temporal variations of the structure constant of turbulent fluctuations of the air refractive index with high correlation in the most part