Experimental Estimation of the Backscatter Enhancement Peak

The intensity distribution of scattered radiation over the transmitting–receiving aperture of a turbulent lidar is experimentally studied. Sounding was performed along a horizontal path under moderate turbulence with a narrow laser beam located in the center of the receiving aperture of variable size. The relative contribution to the echo signal due to turbulence decreased as the receiving aperture increased. The BSE effect was found to be localized at the center of the receiving aperture: the peak of scattered radiation is located at the axis of the sounding beam, and its size is approximately equal to the beam size; at the periphery, the average intensity of scattered radiation slowly decreased to background values as the distance from the beam axis increased. The result can be used in practice for optimal choice of transceiver parameters when designing a turbulent lidar.