主动遥感探测海底可燃冰的正演研究

本文提出利用光学成像干涉技术主动遥感探测可燃冰的温度、压强、浓度物理量。通过光纤将海面上波长为1.65μm的激光传输到海底,激发海底可燃冰,将CH4发射的1.65μm附近相距很近的10条谱线用光纤收集传回到海面上,经过成像干涉系统,在CCD相机上得到5条成像干涉条纹,选择两条相邻干涉条纹的灰度值,利用"转动谱线测温法"和洛伦兹线型即可获得海底可燃冰CH4的温度、压强、浓度等参量。实验得出CH4的正演成像干涉图,并得到CCD上的电子计数1.68×105远远大于拟用CCD噪声400e,系统的最大信噪比为291,窄带干涉滤光片可在16°视场内区分CH4的10条目标谱线,CH4的温度和浓度探测精度分别为1K和3%。研究表明,该成像干涉系统可用于遥感探测海底可燃冰。

Forward measurement of submarine gas hydrates by active remote sensing technology

In this paper, an optical imaging interferometry system was proposed for the accurate detection of the temperature, pressure, and concentration of gas hydrates. As part of this system, laser light with a wavelength of 1.65 μm, was transmitted across the sea surface through a fiber to excite gas hydrates on the sea bed. Ten spectral lines close to the 1.65 μm waves emitted by CH₄ were collected and transmitted to the sea surface through another fiber. Five image interference fringes for CH₄ were obtained on a Charge-Coupled Device (CCD) camera. Using the "rotation line temperature measurement method" and the Lorentzian line profile, and by selecting the gray values of two adjacent interference fringes, the temperature, pressure, and concentration of the CH₄ gas hydrates on the sea bed could be obtained. The forward results of the imaging interferogram for CH₄ show that the electron count on the CCD is 1.68×10⁵, much larger than which results in the noise value of 400e. The maximum signal-to-noise ratio of the system is 291. The narrowband interference filter could distinguish 10 spectral lines in the waves emitted by CH₄ within the 16° field of view. The measuring precision of the CH₄ temperature and concentration values are 1 K and 3%, respectively. This study shows that an imaging interference system can be used in the remote sensing of seabed gas hydrates.