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机载激光拉曼散射雷达技术可以快速获取次表层海水温度的三维分布,具有重要的实用价值和经济价值.首先,从理论上分析了水的伸缩振动拉曼谱峰值位置和半高全宽与激发波长之间的对应关系,发现随着激发波长的增大,拉曼峰逐渐向长波方向移动,且拉曼光谱半高全宽显著增大.然后,实验测量了不同温度下450 nm激光和532 nm激光激发的水的拉曼光谱,对比验证了上述理论分析结果.并采用单高斯峰拟合法分析了两组拉曼光谱,拟合出高斯峰峰值位置与温度之间的关系,分析了激发波长对温度测量精度的影响.研究发现,采用较长波长的激发光可以提高拉曼光谱的测量精度,从而改善测温精度.最后,建立了拉曼散射雷达方程,分析了拉曼散射系数与激光波长之间的关系,研究了激光波长对雷达系统探测深度的影响.结果表明,激光波长对雷达系统探测深度有很大的影响,采用480 nm以下波长的激光时雷达系统探测深度较大,而采用长波段激光时雷达系统探测深度会大幅降低.实际系统设计中选取激光光源时需要综合考虑上述两方面的影响.
Airborne laser Raman scattering radar technology can quickly obtain the three-dimensional distribution of sub-surface seawater temperature, which has important practical value and economic value.Firstly, the peak position of Raman vibrational stretching vibration and the full width at half maximum and excitation wavelength We find that the Raman peaks move to the longwave direction with the increase of the excitation wavelength, and the full width at half maximum of the Raman spectrum increases significantly.After that, the excitation of the 450 nm laser and the 532 nm laser at different temperatures Raman spectra of water were compared and validated by the above theoretical analysis.The Raman spectra of two groups were analyzed by single Gaussian peak fitting method to get the relationship between the peak position of Gaussian peak and temperature.The influence of excitation wavelength on temperature Measurement accuracy.The results show that using longer wavelength of excitation light can improve the measurement accuracy of Raman spectrum and improve the temperature measurement accuracy.Finally, Raman scattering radar equation is established, and Raman scattering coefficient and laser wavelength The relationship between laser wavelength and radar system is studied.The results show that the laser wavelength has a great influence on the detection depth of radar system, The detection depth of the radar system is large when the laser wavelength is below 480 nm, while the detection depth of the radar system is greatly reduced when using the laser of the long wavelength range.Considering the above two aspects when selecting the laser light source in the actual system design.