Yufeng Wang, Xiaoming Cao, Jing Zhang, Liu Tang, Yuehui Song, Huige Di, and Dengxin Hua*
Author Affiliations
School of Mechanical and Precision Instrument Engineering, Xi’an University of Technology, Xi’an, Shaanxi 710048, Chinashow less
Fig. 1. Schematic of Raman lidar system for water vapor measurement
Fig. 2. Comparison of water vapor Raman scattering signals before and after denoising detected in daytime. (a) SNR and RMSE denoised by wavelet basis with different filter lengths; (b) comparison of range-square-corrected results before and after denoising
Fig. 3. Comparison of Mie-Rayleigh scattering signals before and after denoising in daytime. (a) SNR and RMSE denoised by wavelet basis with different filter lengths; (b) comparison of range-square-corrected results before and after denoising
Fig. 4. Denoising results of daytime water vapor Raman scattering signals denoised with different threshold functions
Fig. 5. Denoising results of water vapor Raman scattering signals denoised by different threshold acquisition methods in daytime. (a) RSCS; (b) SNR and RMSE
Fig. 6. Denoising results of Mie-Rayleigh scattering signals denosied by different threshold acquisition methods in daytime. (a) RSCS; (b) SNR and RMSE
Fig. 7. Comparison of lidar detection results before and after denoising in daytime. (a) RSCS of water vapor and nitrogen Raman scattering; (b) water vapor mixing ratio profile; (c) SNR of water vapor detection
Fig. 8. Regression relationship of lidar signal before and after denoising. (a) Mie Rayleigh scattering signal; (b) water vapor Raman scattering signal
Fig. 9. THI displays of water vapor mixing ratio in 2016-09-22 00∶00-2016-09-23 00∶00 before and after denoising. (a) Before denoising; (b) after denoising
Fig. 10. Variation of water vapor mixing ratio taken by meteorological station in 2016-09-22 00∶00-2016-09-23 00∶00
Parameter | Value |
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Laser wavelength | 354.7 nm | Laser energy per pulse | 150 mJ | Laser pulse repetition rate | 20 Hz | Telescope diameter | 600 mm | Field of view | 0.2 mrad | Focal length | 2000 mm | DM1 | R>99% at 350-365 nm,T>90% at 380-430 nm | DM2 | R>99% at 360-395 nm, T>90% at 400-430 nm | Central WL of IF1 | 354.7 nm | Bandwidth of IF1 | 0.5 nm | Peaktransmittance of IF1 | 65% | Central WL of IF2 | 386.7 nm | Bandwidth of IF2 | 0.5 nm | Peaktransmittance of IF2 | 65% | Central WL of IF3 | 407.6 nm | Bandwidth of IF3 | 0.5 nm | Peaktransmittance of IF3 | 65% |
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Table 1. Specification parameters of Raman lidar system