Simulation and Analysis of Mie-Scattering Lidar-Measuring Atmospheric Turbulence Profile

Abstract

Based on the residual turbulent scintillation theory, the Mie-scattering lidar can measure the intensity of atmospheric turbulence by detecting the light intensity scintillation index of the laser return signal. In order to evaluate and optimize the reliability of the Mie-scattering lidar system for detecting atmospheric turbulence, the appropriate parameters of the Mie-scattering lidar system are selected and optimized using the residual turbulent scintillation theory. Then, the Fourier transform method is employed to perform the numerical simulation of the phase screen of the laser light intensity transformation on the vertical transmission path of atmospheric turbulence. The phase screen simulation, low-frequency optimization, and scintillation index calculation methods are provided in detail, respectively. Based on the phase distribution of the laser beam, the scintillation index is obtained. Through the relationship between the scintillation index and the atmospheric turbulent refractive index structure constant, the atmospheric turbulence profile is inverted. The simulation results show that the atmospheric refractive index structure constant profile obtained by the iterative method is consistent with the input HV_5/7 model below 6500 m, which has great guiding significance to carry out actual experiments to measure atmospheric turbulence using the Mie lidar.

Keywords: Mie lidar; atmospheric refractive index structure constant; atmospheric turbulence; residual turbulent scintillation; scintillation index.

Figure 1

The structure diagram of the Mie lidar system.

Figure 2

Spatial correlation scale of light intensity fluctuation $l_{\mathrm{I}}$.

Figure 3

The three-dimensional (left) and two-dimensional (right) schematic diagrams of the emitted beam intensity distribution of the Mie lidar system at z = 0.

Figure 4

Phase screen model of light transmission in atmospheric turbulence.

Figure 5

Schematic diagram of phase screen grid simulation.

Figure 6

Schematic diagram of sub-harmonic compensation.

Figure 7

The three-dimensional (left) and two-dimensional (right) schematic diagrams of the phase distribution of the high-frequency phase screen numerically simulated in the turbulent atmosphere.

Figure 8

The three-dimensional (left) and two-dimensional (right) schematic diagrams of the numerically simulated phase distribution in the turbulent atmosphere after the third harmonic compensation under the same conditions.

Figure 9

Kolmogorov phase screen structure function comparison diagram.

Figure 10

Light intensity distribution of the laser beam on the vertical path (a) $\mathsf{\Delta }z=75 \mathrm{m}, L=1000 \mathrm{m}$, (b) $\mathsf{\Delta }z=75 \mathrm{m}, L=2000 \mathrm{m}$, (c), $\mathsf{\Delta }z=200 \mathrm{m}, L=1000 \mathrm{m}$ (d) $\mathsf{\Delta }z=200 \mathrm{m}, L=2000 \mathrm{m}$.

Figure 11

Spot drift phenomenon of laser transmission (a) $\mathsf{\Delta }z=75 \mathrm{m}, L=2000 \mathrm{m}$, (b) $\mathsf{\Delta }z=200 \mathrm{m}, L=2000 \mathrm{m}$.

Figure 12

Distribution of scintillation index with transmission distance.

Figure 13

The profile of atmospheric refractive index structure constant obtained by the iterative inversion algorithm.